Our Genes / Our Choices . Could We | PBS By Michael Yudell, MPH, American Museum of Natural History and Rob DeSalle, Ph.D., American Museum of Natural History Gregor Mendel, pioneer of genetics and parish priest in the collegiate church at Altbrünn, located in the Czech Republic. When Austrian monk Gregor Mendel's mid-19th century experiments led to the discovery of the basic mechanisms of heredity, the science of genetics was born and humanity took its first small steps towards deciphering the genetic code. Mendel helped set in motion a golden age as scientists around the world grappled with the biological underpinnings of heredity. A Century of Astonishing Progress The focus of scientific inquiry has since moved from Mendel to molecules and from genetics—the study of individual genes and the way traits pass between generations—to genomics, the study of an organism's entire complement of DNA (deoxyribonucleic acid). Today the landscape is dominated by the Human Genome Project , an international research consortium that completed the first draft of the human genetic code in June 2000.

The end product—the complete sequence of all 3.1 billion base pairs of DNA contained in almost every human cell—is an encrypted blueprint for human life. To understand the amount of data contained in the human genome, imagine 58 New York telephone books written in A's, C's, T's, and G's. ï¿½AMNH No one could have predicted that only a century after Mendel, scientists would begin to master the DNA molecule itself. How did we reach this point? How did science progress from thinking about the mechanisms of heredity in the broadest possible terms, to understanding that genes are the basic units of heredity, to deciphering and finally manipulating the DNA codes that underlie all life on earth? The story is one of persistence, intuition, and just plain luck. From Pea Plants to Fruit Flies Spurred by the publication of Charles Darwin's Origin of Species in 1859, most biological thought at the time of Mendel's discoveries was preoccupied with solving the riddles of evolution. Published in an obscure scientific journal, Mendel's work gathered dust for almost 40 years.

Remarkably, it was rediscovered in 1900 by three botanists working in separate laboratories across Europe. During the first decades of the 20th century, plant genetics was superseded by research on insects and animals, and Mendel's fundamental laws—which explain how traits are passed from generation to generation—were tested across a wide range of species. Astonishingly prolific and possessing only four pairs of chromosomes , Drosophila melanogaster (aka the fruit fly) has been the workhorse of geneticists for almost a hundred years. Beginning early last century, Thomas Hunt Morgan and his students at Columbia University began breeding fruit flies by the hundreds of thousands. At the time, the terminology of what we now call genetics was not even in place. Botanist William Bateson named the field in 1906, and three years later German biologist Wilhelm Johannsen coined the term " gene ." In 1910 a lone white-eyed male fly appeared in Morgan's laboratory. Formerly critical of Mendel's theories, Morgan came to embrace them when they were able to accurately describe the transmission of this trait across generations. He called such a trait a mutation .

Morgan used mutations to move beyond the laws that managed heredity to examine the specific mechanisms—the genes themselves—that carry out the process. By finding and breeding hundreds of visible mutants, including those with variations in body color and wing shape, he and his collaborators were able to create chromosome maps that showed where on each of Drosophila's four chromosomes certain genes lay—an early map of the fruit fly genome. Eugenics—The Dark Side of Genetic Theory While scientific thinking about genetics was focused on the work of Morgan and his colleagues during the first three decades of the 20th century, a group of men and women known as eugenicists dominated the public discourse. Eugenics is the science of improving the qualities of humanity through selective breeding. Fed by anti-immigration sentiment and a belief in the genetic superiority of some races, the eugenics movement stoked racial hatred and led to discriminatory laws and the sterilization of approximately 30,000 allegedly "feeble-minded" Americans. Fortunately, eugenics faded from the national spotlight almost as swiftly as it had risen, a transition hastened by the horrors of the Holocaust and by advances in genetics and evolutionary and population biology.

Molecular Genetics Overtakes Classical Genetics As some biologists established a mathematical framework for the way in which traits are passed down through generations, others struggled to determine the chemical components of whatever the hereditary material might be. Some remained wedded to the belief that proteins transmitted traits between generations, while others argued that nucleic acids were the fundamental building blocks of life. In 1944, a series of ingenious experiments conducted by three American biologists on the bacteria pneumococci (which causes pneumonia) established that genes are made up of DNA. This discovery unleashed what evolutionary biologist Ernst Mayr called a "veritable 'avalanche' of nucleic-acid research" as biochemists rushed to uncover the physical structure and chemical characteristics of DNA. Enter the Double Helix In the 1950s, at the Cavendish Laboratories in Cambridge, England, scientists developed X-ray crystallography, a technology that made it possible to interpret the three-dimensional structure of a crystallized molecule.

It allowed Maurice Wilkins and Rosalind Franklin to take "snapshots" of DNA that were used in 1953 by James Watson and Francis Crick to build their now-famous model: they discovered that DNA was shaped like a spiral staircase, or double helix. One of Watson and Crick's original models for the structure of DNA, displayed in AMNH's exhibit "The Genomic Revolution." Roderick Mickens ï¿½AMNH Watson and Crick's greatest strength lay in their ability to reconcile their model with existing science. As late as 1933 Thomas Hunt Morgan pointed out that there was "no consensus opinion amongst geneticists as to what the genes are—whether they are real or purely fictitious." Working on instinct, Morgan couldn't be sure that his gene maps were more than a wild goose chase. But beginning with the 1944 discovery that DNA was indeed the "stuff" of heredity, the existence of genes became less and less theoretical. Watson and Crick's discovery of the actual physical structure of DNA finally created a consensus among geneticists that genes were real.

With the basics of heredity now worked out, their successors began to examine and manipulate genetic processes at the molecular level. Delving Deeper Into the Cell The other major players at the molecular level are proteins—structures that are made of amino acids and that govern cell function. In the 1950s, chemist Fred Sanger figured out how to determine the order of amino acids in a given protein. That proteins consist of linear arrays of twenty amino acids and genes consist of linear arrays of four nucleic acids, or bases (DNA), could mean only one thing. Some kind of code connected the information in the DNA to the production of proteins. The rigorous thinking and experimentation required to solve the puzzle attracted some of the greatest scientific minds at work in mid-century. In the 1960s, Crick and chemist Sydney Brenner determined how DNA instructs cells to make specific proteins: a different triplet of bases in the DNA—called codons—codes for each of the twenty amino acids, chains of which build the various proteins. More and more codons were identified over the next few years, and the code eventually turned out to be the same in all organisms, from ferns to flamingos.

Meanwhile, biochemists were taking the cell apart to determine how DNA was replicated, how proteins were synthesized, and what role enzymes played. In 1958 Arthur Kornberg and Severo Ochoa were the first to synthesize DNA molecules in a test tube. They went on to discover a broad array of enzymes and proteins important in DNA replication and the translation of proteins. Others were busy manipulating bacteria to expedite analysis of DNA and genes. A technology called recombinant DNA—cutting DNA from one organism and inserting it into the DNA of another—was invented in 1972, creating the field of genetic engineering. This enormously important development made it possible to clone and modify genes, establishing a foundation for modern biotechnology. For example, colonies of bacteria are now being used to economically manufacture insulin and human growth hormone. The newest PCR machine, the DNA Engine Tetrad, amplifies a target sequence of DNA into more than a million copies in just a few hours. Meg Carlough ï¿½AMNH Technologies that enabled scientists to see and manipulate specific DNA sequences also evolved.

A crucial breakthrough was the invention of polymerase chain reaction (PCR) by Kary Mullis in 1983, a process that generates trillions of copies of a specified segment of DNA in a matter of hours. PCR transformed molecular biology by making genetic material in quantities large enough to allow experimentation. All these discoveries set the stage for the first sequencing of an entire genome, that of a tiny virus called PhiX0174, in 1977. The sequence itself unveiled many unknowns about genes and gene structure, a theme that played out over and over as more genomes were sequenced: a bacterium in 1995; the first higher organism, the roundworm C. elegans, in 1998; the fruit fly in March 2000; and three months later, the human being. Moving Beyond the Genome Now that the human genome has been sequenced, the emphasis is shifting to proteomics: the study of all the proteins for which genes code. The approximately 30,000 genes defined by the Human Genome Project translate into 300,000 to 1 million proteins.

While a genome is relatively fixed, the proteins in any particular cell change dramatically as genes are turned on and off in response to their environment, directing an astonishing range of biological functions with exquisite precision. Molecular biologists are now beginning to unravel the complex ways in which genes interact with each other and with the environment to produce a multiplicity of outcomes. We continue to gather and analyze information about both human and non-human genomes at an astonishing pace. The Risks and Rewards of Genetic Technologies The ability to manipulate DNA makes us capable of doing immense harm to ourselves and our environment, just as it holds out vast promise for improving our lives in ways as yet unseen. Emerging technologies may increase the potential for genetic discrimination and the invasion of genetic privacy. Some worry about the environmental consequences of altering the genomes of various plants and animals. As our skills and knowledge grow, we need to think hard about dealing with such potential consequences. There is no doubt, however, that genomic technologies will change our lives for the better. Comparative genomics, which compares whole genome sequences from a range of organisms, will advance our understanding of the natural world and the role genes play in complex human diseases. Mice, for example, have many gene sequences identical to humans, yet gene functions often differ.

By comparing gene function between mice and humans, or between humans and other species, we will begin to unravel many genetic mysteries. Microarray technology, which enables scientists to compare tens of thousands of genes at once, promises to unlock the genetic roots of diseases and to enhance our ability to treat them. The new field of pharmacogenomics will usher in an era of personalized medicine. Cancer patients, for example, will receive therapies tailored to their specific conditions rather than undergoing ineffective and debilitating treatments. There may even come a time when geneticists begin to manipulate our genes to increase human life spans, creating a veritable fountain of youth. Finally, as we sequence the genomes of more and more species, our understanding of the tree of life and our place in the natural world will deepen. Contemplating the mechanisms and meaning of heredity, scientists a century ago wondered, "Could we?" We could, and we did. And the sequencing of the human genome is another milestone on the age-old quest to understand our origins and decode our biological destiny. History of Genetics History of Genetics By Dr Ananya Mandal, MD Genomics involves the study of genes, genetics, inheritance, molecular biology, biochemistry, biological statistics and incorporates the knowledge of advanced technology, computer science and mathematics.

Mid to Late 19th Century The origins of genetics lie in the development of theories of evolution. It was in 1858 that the origin of species and how species variability was developed after the research work of Charles Darwin and Wallace. They described how new species arose via evolution and how natural selection occurred to evolve new forms. They however did not know the role genes had to play in this phenomenon. Around the same time Gregor Mendel, an Austrian monk, was performing extensive experiments on inheritance and genetics of sweet pea plants. He described the unit of heredity as a particle that does not change and is passed on to offspring. His work is in fact the basis of understanding the principles of genetics even today. Consequently, Gregor Mendel is known as the Father of Genetics. There was, however, little awareness of Gregor’s work during this time. Also in this period Haeckel correctly predicted that the heredity material was located in the nucleus. Miescher showed the material in the nucleus was a nucleic acid. Chromosomes as units carrying genetic information was also discovered around this time.

Early 20th Century It was during this time that the Mendelian Principles and the Chromosomal Theory of Inheritance was established. Mendel’s work was largely unknown. It was not until 1900 that there was a rediscovery of the Mendelian principles and publications began citing his work. Development of the chromosomal theory led to advent of the field of cytogenetics. The first observations of chromosomal abnormalities (e.g. duplications, deletions, translocations, inversions) were reported around this time. Mid 20th Century It was in 1870s that the material in the nucleus was determined to be a nucleic acid. DNA was determined to be the genetic material between 1920s and mid-1950s. Griffith’s experiments with a bacterial strain established the theory. Avery, MacLeod and McCarty further showed that DNA, not protein or RNA was the factor responsible for genetic inheritance and evolution of the bacterial strains studied by Griffith. It was then that Watson and Crick in their groundbreaking work determined the structure of DNA, and others suggested that DNA contained a genetic code. The code was discovered in the 1960’s.

Crick discovered the process of transcription and translation and led to formation of the “central dogma of molecular biology”. Mid-late 20th Century and the Early 21st Century This period heralded the concept of molecular biology and molecular genetics. Various advanced technologies made their way into knowledge base around this time. This included molecular biology, recombinant DNA technology, and biotechnology methods. Methods of radiolabelling of the DNA with radioactive or fluorescent tags for development of diagnostic and therapeutic methods as well as research tools were discovered during this time. Restriction enzymes were discovered and used to construct recombinant DNA molecules that contained foreign DNA that could be grown in abundance in bacterial strains. Then came methods like PCR (Polymerase chain reaction) and host of other biotechnology methods and new applications were found in medicine, pharmacotherapeutics as well as research.

Mid to Late 19th Century: Evolution, Natural Selection, Particulate Inheritance and Nuclein 1858 Darwin and Wallace - Role of natural variation and natural selection in evolution 1865 - Gregor Mendel - Particulate inheritance 1866 - Ernst Haeckel; Heredity materials was in the nucleus 1871 - Friedrich Miescher; Material in the nucleus was a nucleic acid Related Stories Early 20th Century: Mendelian Principles are extended and the Chromosomal Theory of Inheritance solidifies 1900 - Correns, de Vries, von Tschermak - Mendel’s work is rediscovered;The age of genetics begins 1902 - Walter Sutton and Theodor Boveri - Chromosomal Theory of Inheritance; The heredity material resides in chromosomes 1905-1923 Number of linkage groups - number of chromosomes Lethal genes 1908 - Hardy and Weinberg - Hardy-Weinberg principle of genetic equilibrium 1909 - Nilsson-Ehle - Theory of quantitative traits and quantitative genetics Mid 20th Century: DNA is the stuff of life

; the preeminence of the Darwinian theory of evolution via natural selection is confirmed 1928 - Griffith - Transformation experiments 1944 - Avery, MacLeod, McCarty - Definitive proof that DNA is the genetic material 1953 - Watson and Crick - DNA structure is defined 1954-1961 The Top Ten Most Important Scientists in Genetics The Top Ten Most Important Scientists in Genetics written by: Paul Arnold •edited by: Paul Arnold •updated: 5/31/2009 You may agree, or disagree with my selection of famous scientists; personal lists are always arbitrary affairs, but here goes with my list of candidates for the top ten most import scientists in genetics.

slide 1 of 2 Gregor Mendel – the Austrian monk and his love of garden peas created a seismic shift in biological thinking when he came up with the laws of inheritance . Francis Crick and James Watson – joint entrants for their landmark 1953 paper on the structure of DNA. They cracked the secret of life when they worked out the double helix structure. They were awarded the Nobel Prize for Physiology or Medicine in 1962. Erwin Chargaff - his work laid the foundations for Crick and Watson's discoveries. By studying various organisms he observed that the ratio of the nucleic acid bases adenine to thymine was roughly equal, and that the ratio of cytosine to guanine was also roughly equal. Oswald Avery - certainly an unsung hero in the history of genetics - it was his work in 1944 that concluded that DNA (the so-called "transforming principle") transmitted the hereditary information. Alec Jeffreys - was the scientist who invented DNA fingerprinting; a technology that has many applications such as solving crimes, paternity testing, and resolving immigration disputes. It was first used in the courtroom in 1986.

Rosalind Franklin – sometimes referred to as the ‘dark lady of DNA.’ Her work on the X-ray diffraction images of DNA was vital to helping Crick and Watson come up with their hypothesis on the structure of DNA. Her contribution went largely unrecognised during her lifetime, and she was not awarded the Nobel Prize that Crick and Watson shared with Maurice Wilkins because she had died in 1958. The award is not given posthumously. Herb Boyer - co-founder of the biotech giant Genentech Inc, and a pioneer in the field of recombinant DNA technology. He and Stanley Norman Cohen created the world's first genetically engineered organism . Frederick Miescher - the man who discovered DNA. He discovered it in 1869 whilst studying white blood cells from pus-soaked bandages. He called the genetic material 'nuclein' because it had come from the nucleus. He did not know that it was the hereditary material. Gregor Mendel - Biography, Facts and Pictures Gregor Mendel Gregor Mendel is the father of genetics. He: • Founded the science of genetics. • Identified many of the rules of heredity.

These rules determine how traits are passed through generations of living things. • Saw that living things pass traits to the next generation by something which remains unchanged in successive generations of an organism – we now call this ‘something’ genes. • Realized that traits could skip a generation – seemingly lost traits could appear again in another generation – he called these recessive traits. • Identified recessive and dominant traits which pass from parents to offspring. • Established, momentously, that traits pass from parents to their offspring in a mathematically predictable way. Mendel’s work only made a big impact in 1900, 16 years after his death, and 34 years after he first published it. Advertisements Mendel’s Education and the Abbey of St. Thomas Johann Mendel (he wasn’t called Gregor until later) was born July 20, 1822, in Heinzendorf bei Odrau. This small village was in the Austrian Empire, but is now in the Czech Republic. Mendel’s parents were small farmers who made financial sacrifices to pay for his education.

He did well enough at high school to make it, aged 18, to the University of Olomouc in 1840. The university was about 40 miles (60 km) from his home village. He took courses in physics, mathematics and philosophy. You want to keep doing science? You need to be a monk! In 1843, aged 21, and in financial difficulty, one of his teachers, Professor Friedrich Franz, a physicist, advised Mendel to join the Abbey of St. Thomas in Brünn as a monk. The Abbey actually had a good reputation for its teaching of sciences, and its director, Abbot Franz Cyril Napp, was particularly interested in heredity of traits in plants and animals on farms. If he could join the Abbey, he could continue studying science, while ensuring he could get by financially. And so Mendel, who was more interested in science than religion, became a monk. The move to Brünn carried him much farther away from his home village. On joining the Abbey, he took the name Gregor. From then on he ceased to be Johann Mendel and became Gregor Mendel.

Learning and Teaching Science In 1846, aged 24, Mendel took fruit-growing classes given by Professor Franz Diebl at the Brünn Philosophical Institute. Diebl was an authority on plant breeding. Mendel became a priest in 1847 and got his own parish in 1848. He did not enjoy working as a parish priest and got a job as a high school teacher in 1849. In 1850, aged 28, he failed exams which would have qualified him as a high school teacher. A year later, he went to the University of Vienna where he studied chemistry, biology and physics. The idea was that by strengthening his knowledge in these subjects, he could qualify as a high school teacher. Two years later, after completing his studies, he returned to the monastery in 1854 and took a position as a physics teacher at a school at Brünn, where he taught for the next 16 years. Research and Admin In 1856, aged 34, he again failed to qualify formally as a high school teacher. This time, illness prevented him completing the exams.

In the same year, he began his major, groundbreaking study of heredity in plants. In 1865, still interested in physical science, he founded the Austrian Meteorological Society. In fact, during his life, Mendel published more about meteorology than he did biology! In 1866, he published his heredity work. Unfortunately, most people who read it did not recognize the intellectual gold that his paper contained. In 1867, aged 45, he became Abbot of his monastery and devoted himself to its smooth running as its administrator. At the monastery in Brünn in the early 1860s. Mendel is pictured back right, looking at part of a plant in his left hand. Abbot Franz Cyril Napp sits in the front row, wearing a large cross. Abbot Napp encouraged Mendel’s science and heredity studies. Mendel and Genetics: Experiments with Peas: 1856 to 1863 During his time in Olomouc, Mendel had made friends with two university professors: Friedrich Franz, a physicist, and Johann Karl Nestler, an agricultural biologist, who was interested in heredity.

Nestler passed his interest in heredity to Mendel, who was intrigued by the subject. Mendel’s monastery had a 5 acre (2 hectare) garden, and his two former professors encouraged Mendel to pursue his interest in heredity by using the garden for experiments. Abbot Franz Cyril Napp and Professor Franz Diebl also encouraged him to follow this path. Mendel was unhappy with how inheritance of traits was being explained People had known for millennia about selective breeding. They knew that by breeding from those individuals that showed the most desirable traits, future generations were more likely to show these desirable traits. Guard dogs might be bred from parents that were loyal and friendly to their owners, but were suspicious or even aggressive with strangers. Cattle might be bred from cows that yielded most milk and bulls that yielded most meat. Wheat might be kept and sown the following year from those plants which had produced the most abundant crop. The main theory of heredity in Mendel’s time was that offspring were a smooth blend of their two parents’ traits. Mendel set himself the very ambitious task of discovering the laws of heredity.

To achieve this, he embarked on a mammoth sized, highly systematic, eight year study of edible peas, individually and carefully recording the traits shown by every plant in successive generations. His work involved growing and recording the traits in about 30,000 plants. One of the keys to his success was breeding from closely related pea varieties which would differ in only a small number of traits. The seven traits of pea plants that Mendel chose to study: seed wrinkles; seed color; seed-coat color, which leads to flower color; pod shape; pod color; flower location; and plant height. Image by Mariana Ruiz. Mendel’s Results for Flower Color Mendel found the same results for all traits, but we’ll look at flower color as an example. When Mendel bred purple-flowered peas (BB) with white-flowered peas (bb), every plant in the next generation had only purple flowers (Bb). When these purple-flowered plants (Bb) were bred with one-another to create a second-generation of plants, some white flowered plants appeared again (bb). Mendel realized that his purple-flowered plants still held instructions for making white flowers somewhere inside them.

He also found that the number of purple to white was predictable. 75 percent of the second-generation of plants had purple flowers, while 25 percent had white flowers. He called the purple trait dominant and the white trait recessive. A Punnett Square. Both of the starting plants have purple flowers but they contain the genes for purple (B) and white (b). The pollen from the male plant fertilizes the egg in the female flower. In this variety of plant, purple flowers are caused by a dominant gene (B). Dominance is indicated by a capital letter. White flowers are caused by recessive genes, indicated by the small letter (b). Both the male and female parent plants in the diagram above carry the dominant gene B for purple and the recessive gene b for white flowers. The ratio of purple flowers to white flowers in their offspring will be 3:1 as shown in this diagram. For a white flower to appear, the offspring must inherit the recessive gene from both parents. Purple appears with any other combination of genes inherited from the parent plants.

Image by Madeleine Price Ball Mendel’s Conclusions Mendel’s most important conclusions were: The inheritance of each trait is determined by something (which we now call genes) passed from parent to offspring unchanged. In other words, genes from parents do not ‘blend’ in the offspring. For each trait, an organism inherits one gene from each parent. Although a trait may not appear in an individual, the gene that can cause the trait is still there, so the trait can appear again in a future generation. Scientists who did research later found that Mendel’s results do not only apply to pea plants. Trait inheritance in most plants and animals, including humans, follows the patterns Mendel recorded. In Mendel’s honor, these very common patterns of heredity are now called Mendelian Inheritance. Fast Forward to 1900: The Sleeping Giant Awakes In 1900, three scientists independently carrying out heredity research got exciting results. However, when they searched the literature, they realized their results were not really new. Their results actually verified the forgotten results Mendel had published 34 years earlier.

Mendel’s results gave the scientists of 1900 greater confidence in their own results and the new science of genetics was truly born. The scientists were Carl Correns, Hugo de Vries, and Erich von Tschermak. “I thought that I had found something new. But then I convinced myself that the Abbot Gregor Mendel in Brünn, had, during the sixties, not only obtained the same result through extensive experiments with peas, which lasted for many years, as did de Vries and I, but had also given exactly the same explanation, as far as that was possible in 1866.” Carl Erich Correns, 1864 to 1933 Geneticist and Botanist Mendel’s Results Were “Too Good” Mendel’s published work was rather vague about detailed experimental procedures, including dates. Enter Ronald Fisher, a very eminent geneticist and statistician. It was Fisher who first used the term ‘null hypothesis’ in statistical testing. In 1936, Fisher tried to reconstruct on paper the way Mendel carried out his experiments.

He also wanted to discover why Mendel’s work had been overlooked for so long until it was rediscovered in 1900. He found that, although some people in a position to see the importance of Mendel’s work had actually read it, they did not realize its importance. Their minds were unreceptive to Mendel’s words and ideas. They may have believed he was repeating plant hybridization work others had already carried out. Controversially, Fisher said that his statistical analysis of Mendel’s results showed too few random errors to have come from real experiments. Nearly all of Mendel’s data showed an unnatural bias. Fischer wrote: “Although no explanation can be expected to be satisfactory, it remains a possibility among others that Mendel was deceived by some assistant who knew too well what was expected. This possibility is supported by independent evidence that the data of most, if not all, of the experiments have been falsified so as to agree closely with Mendel’s expectations.” Ronald Fisher, 1890 to 1962 Statistician, Geneticist, Evolutionary Biologist Fisher’s analysis said there was only a 1 in 2000 chance that Mendel’s results were the fully reported results of real experiments.

The controversy begun by Fisher continues to this day, with a steady stream of publications seeking to give reasons for Mendel’s results. One possibility is that results from ‘bad’ experiments were discarded to leave only the results of ‘good’ experiments. Another is that the results arose from an unconscious bias on the part of the experimenters. The End Gregor Mendel was unaware of the new science of genetics which he had founded, and unaware of any future controversies. He died of a kidney disease, aged 61, on January 6, 1884. Advertisements Author of this page: The Doc Images of scientists digitally enhanced and colorized by this website. © All rights reserved. Please use the following MLA compliant citation: "Gregor Mendel." Famous Scientists. famousscientists.org. 19 Jul. 2014. Web.

< 7 Scientists whose ideas were rejected during… 11 great scientists who were part-timers Scientists Behaving Badly Gregor Mendel: A Monk and His Peas | Genetics Gregor Mendel: A Monk and His Peas By Heather Whipps | June 5, 2008 02:38pm ET MORE Oil Painting of Abbot Gregor Mendel. Mendel conducted his famous experiment at the Abbey of St. Thomas in what is now Brno, Czech Republic. He was elected Abbot of the St. Thomas friars in 1868, after which he had little time for science. Mendel may have been disheartened by the lack of reaction to his pea paper, but he knew that his discovery was important. Not long before his death in 1884, he told a scientific colleague, "My time will come." Credit: Field Museum, Stepan Bartos Kids may wrinkle their noses at peas, but scientists grant a lot more respect for the enormous role the little green legume seeds played in the history of genetics.

Working in the solitude of an Austrian monastery, one 19th-century holy man managed to unravel the basic principles of heredity with just a handful of pea species that he bred and crossbred, counted and catalogued with monastic discipline. While plant and animal genes were Gregor Mendel's original focus , his ideas later made sense of our complex human workings, too, kicking off the scientific discipline of genetics . An unconventional scientist Today, Mendel is revered as the father of genetics, but the Austrian's work on heredity didn't initially make the kind of big splash in the science world achieved, for example, by his contemporary, Charles Darwin. Mendel wasn't a traditional scientist, however. Gregor Johann Mendel was born July 20, 1822 in a region of Austria that’s now part of the Czech Republic. He grew up on the family farm and worked as a gardener. He also studied beekeeping. Despite working for a time as a primary and secondary school teacher and studying at the University of Vienna, Mendel was first and foremost a full-time monk.

Mendel lived at the Augustinian Abbey of Brno (then part of the Austro-Hungarian Empire) from 1843 until his death in 1884, acting as its revered Abbott for more than half of those years. When Mendel began his experiments on the pea plants of the monastery garden in 1856, at first merely to develop new color variants and then to examine the effects of hybridization, it was independent of any university and well outside of the public eye. Some genes are bossier In the 19th century, it was commonly believed that traits — whether plant, animal or human — were passed on to offspring in a blend of characteristics "donated" by each parent. Heredity was a poorly understood in general, and the concept of a gene did not exist at all. It was in this scientific environment that Mendel set out to study 34 subspecies of the common garden pea, a vegetable noted for its many variations in color, length, flower, leaves and for the way each variation appears clearly defined.

Over eight years, he isolated each pea trait one at a time and crossbred species to note what traits were passed on and what traits weren't from one generation to the next. Mendel's meticulous study produced astonishing results: Not only did the monk discover the idea of dominant and recessive traits, he was able to apply a consistent mathematical formula that explained the frequency with which each trait appeared. His discoveries would be summarized into some basic principles: That each inherited trait is determined by units (what we'd later call a gene) passed on independently of other traits. That each trait is made up of two units, one received from each parent. That though one unit of a trait may be inherited but not expressed in the individual, that "hidden" trait can still be passed on to successive generations. Mendel gets his due eventually The importance of Mendel's work wouldn't be recognized for another 40 years, well after his death. The monk's relative obscurity in scientific circles meant that few institutions took notice of his original published results. His forgotten papers resurfaced only after further work in genetics began to make some sense of his then-unconventional theories.

The chromosome theory of inheritance, or the idea that we receive a combination of traits from each parent carried on a set of distinct pairs, was proposed in 1902 and was the first study to rely heavily on Mendel's ideas of dominant and recessive traits. When Mendel's principles were fully incorporated in the early 20th century, genetics really took off. By 1909, a handful of funny-sounding names such as alleles, zygotes and others were finally pinned to the things Mendel had first described in his humble experiments, and scientists launched into a century-long frenzy to explain how all of our biological quirks and quarks came to be. This article, adapted and updated, was originally part of a LiveScience series about People and Inventions that Changed the World . Author Bio Heather Whipps, Heather Whipps writes about history, anthropology and health for Live Science. She received her Diploma of College Studies in Social Sciences from John Abbott College and a Bachelor of Arts in Anthropology from McGill University, both in Quebec. She has hiked with mountain gorillas in Rwanda, and is an avid athlete and watcher of sports, particularly her favorite ice hockey team, the Montreal Canadiens. Oh yeah, she hates papaya.

Latest on Gregor Mendel: A Monk and His Peas | Genetics Genetics - humans, body, used, plants, chemical, characteristics, form, animals, cells Genetics Genetics Photo by: Andrea Danti Genetics is the branch of biology concerned with the science of heredity. The term heredity refers to the way in which specific characteristics are transmitted from one generation to the next. For example, we know that a tall mother and a tall father tend to have children that are tall. Geneticists (scientists who study genetics) are interested in finding out two things about this observation. First, what is there in the cells of a person's body that directs the body to become tall rather than short. Second, how are the directions for "tallness" transmitted from parent to offspring, from one generation to the next? The history of genetics Humans have known about hereditary characteristics for thousands of years. That knowledge has been used for the improvement of domestic plants and animals. Until the late nineteenth century, however, that knowledge had been gained by trial-and-error experiments. The modern science of genetics began with the pioneering work of the Austrian monk and botanist Gregor Mendel (1822–1884).

Words to Know DNA (deoxyribonucleic acid): Molecules that make up chromosomes and on which genes are located. Dominant gene: The state or genetic trait that will always express itself when present as part of a pair of genes in a chromosome. Gene: A section of a DNA molecule that carries instructions for the formation, functioning, and transmission of specific traits from one generation to another. Heredity: The transmission of characteristics from parents to offspring. Nucleotide: A group of atoms present in a DNA molecule. Proteins: Large molecules that are essential to the structure and functioning of all living cells. Recessive gene: The state or genetic trait that can express itself only when two genes, one from both parents, are present and act as a kind of code for creating the trait, but will not express itself when paired with a dominant gene. Triad: Also known as codon; group of three nucleotides that carries a specific message for a cell. Mendel studied the genetic characteristics of pea plants. He was interested in finding out how certain traits, such as flower color and plant height, were passed on from generation to generation.

During his lifetime, he studied dozens of generations of plants of all sizes, shapes, and colors. As a result of his research, Mendel was able to state a few basic laws describing the way genetic traits are inherited. He also came to the conclusion that there must be a specific biological unit responsible for the transmission of genetic traits. He called that unit a factor. Mendel's "factors" were later given the name of genes. Without question, Mendel was the father of the modern science of genetics. One of the great ironies of history, however, was that his discoveries were lost for more than three decades. Then, in the early 1900s, Mendel's research was rediscovered almost simultaneously by three different biologists, the Dutch botanist Hugo de Vries (1848–1935), the German botanist Karl F. J. Correns (1864–1933), and the Austrian botanist Erich Tschermak von Seysenegg (1871–1962). Although interest in genetics grew rapidly after 1900, a fundamental problem remained.

Geneticists based all of their laws, theories, and experiments on the concept of the gene. But no one had any idea as to what was a gene. It seemed clear that the gene was probably some kind of chemical compound, or some combination of compounds. But no one had been able to determine exactly what kind of compound or compounds it was. The answer to that question came in 1953. The American biologist James Watson (1928– ) and the English chemist Francis Crick (1916– ) collaborated to discover that a gene was a section of a very large and complex molecule found in the nuclei of all cells, the deoxyribonucleic acid (DNA) molecule. The chemistry of genes Imagine a very long chain of beads strung together to form a strand containing hundreds of thousands of beads. The strand contains beads of only four colors: red, yellow, blue, and green. That strand of beads can be compared to half of a DNA molecule. The other half of the molecule is a second strand almost identical to the first strand. Watson and Crick showed that the sequence in which various colors of beads occur is significant.

A DNA molecule in which the beads are arranged in the sequence blue-yellow-yellow-red-red-blue-blue-blue-, and so on, has meaning for a cell. The sequence tells the "chemical machinery" of the cell to make a certain kind of protein, such as the protein responsible for red hair or blue eyes. Another sequence of colors, for example, red-red-yellow-green-blue-green-red-, and so on, might be the "code" for making blonde hair or green eyes. The components of a DNA molecule are not, of course, colored beads. They are certain groups of atoms known as nucleotides. Each nucleotide in a DNA molecule is comparable to one of the colored beads in the analogy above. Just as there are only four colors of beads in the above analogy, so there are only four different nucleotides in DNA molecules. Those nucleotides might be represented by the symbols A, C, G, and T (corresponding to bead colors of red, blue, green, and yellow).

A DNA molecule, then, is a very long chain of nucleotides with a structure something like the following: -C-T-A-T-C-G-A-C-T-T-G-A-C-T-T-T-G-C-C-A-C-A-A-C- … The dots at the end of the chain indicate that the chain actually goes on much, much longer. Watson and Crick said that each set of three nucleotides—they called them triads or codons—carried a specific message that cells could understand. Those messages told a cell to "make red hair," or "make blue eyes," or "help a person to grow tall," or "give a person musical talent," or any one of thousands of other traits that each human possesses. Francis Crick (right) and James Watson display their model of DNA's structure. This discovery answered the first question that geneticists had about heredity: how cells know which traits they are "supposed" to make and what functions they are "supposed" to carry out. The same discovery also answered the second question puzzling geneticists: how do these traits get passed down from generation to generation? The answer to that question is that DNA molecules have the ability to make copies of themselves.

When a cell divides (reproduces), so do the DNA molecules it contains. In most cases, two exactly identical molecules are produced from a single parent molecule. When an egg cell (female reproductive cell) and a sperm cell (male reproductive cell) unite during fertilization, each cell provides DNA to the fertilized egg. The DNA from both parents combines to form DNA for the offspring. Whatever nucleotide sequences the mother and father had in their own cells, they pass on to their child. Dominant and recessive traits One fundamental question remains in the above example: suppose that a child is born to a father with red hair and a mother with blonde hair. What color hair will the child have? Strands of DNA. (Reproduced by permission of The Stock Market .) Mendel worked with this question long before Watson and Crick discovered the nature of DNA. He found that for any one genetic trait, there were always two possible conditions. A flower might be red or white; a plant might be tall or short; a pea pod might be smooth or wrinkled; and so on. Mendel also discovered that one of these two conditions was more likely to "win out" over the other.

He called the "winner" the dominant trait and the loser the recessive trait. If a pea plant inherits a "tall" gene for height from both parent plants, the offspring is most like to be tall. If the pea plants inherits a "short" gene for height from both parent plants, the offspring is most likely to be short. But if the pea plant inherits a "tall" gene from one parent and a "short" gene from the second parent, the offspring is most likely to be tall. An important part of Mendel's work was finding out what the mathematical chances of various kinds of combinations might be. For example, he showed how to calculate the probabilities that would result when a "tall" parent pea plant was crossed with a "short" parent pea plant in the first, second, and succeeding generations. The future of genetics One can apply the principles of genetics in a great many situations without knowing anything about the structure of DNA molecules. However, the Watson-Crick discovery made possible a revolutionary change in the basic nature of genetics. As long as scientists had no idea as to what a gene was, there was not much they could do to make changes in the genes of a plant, animal, or human.

But Watson and Crick showed that genes are nothing other than chemical compounds. If someone can make changes in chemical compounds in a laboratory, that person can also make changes in a DNA molecule. The problems faced are a good deal more difficult since DNA molecules are far more complex than most molecules that chemists work with. But the basic principles involved are the same. Scientists are exploring a variety of ways in which genes can be modified to produce cells that can do things they could not do before. For example, it is possible to create the gene for the hormone (chemical messenger) known as insulin in a chemical laboratory. The work is fairly difficult, but by no means impossible. It simply requires that the correct atoms be assembled in the correct sequence. That artificial gene can then be inserted into the DNA of other organisms, such as bacteria. When the artificial gene becomes part of the bacterial DNA, it begins to function just like all the other genes in the bacteria's DNA. The bacteria begins to function as an "insulin factory," making a vitally important compound that it could never make before. One of the most exciting recent developments in genetics is the initiation of the Human Genome Project, which officially began on October 1, 1990.

This project is designed to provide a complete genetic road map outlining the location and function of the approximately 50,000 genes in human deoxyribonucleic acid (DNA) and to determine the sequences of the 3,000,000,000 base pairs that make up human DNA. As a result, genetic researchers will have easy access to specific genes to study how the human body works and to develop therapies for diseases. Gene maps for other species of animals also are being developed. There appears to be virtually no technical limit to the things that scientists can do with genes. But with the promise of genetic research, many ethical and philosophical questions arise. One question is, of course, whether there are social or ethical limits to the kinds of changes scientists ought to be allowed to make in the genes of plants, animals, and humans. With research focusing on the ability to manipulate genes, there is the fear that the results will not always be beneficial. For the most part, the benefits for medicine and agriculture seem to far outweigh the possible abuses, and genetic research continues.

Gregor Mendel & Genetics: Experiments, Laws & Discovery - Video & Lesson Transcript | Study.com Gregor Mendel & Genetics: Experiments, Laws & Discovery Watch short & fun videos Start Your Free Trial Today An error occurred trying to load this video. Try refreshing the page, or contact customer support. You must create an account to continue watching Register for a free trial Are you a student or a teacher? I am a student Start Your Free Trial To Continue Watching As a member, you'll also get unlimited access to over lessons in math, English, science, history, and more. Plus, get practice tests, quizzes, and personalized coaching to help you succeed. Coming up next: Theory of Evolution You're on a roll. Keep up the good work! Your next lesson will play in 10 seconds 0:01 Gregor Mendel Add to Add to Add to Want to watch this again later? Log in or sign up to add this lesson to a Custom Course. Custom Courses are courses that you create from Study.com lessons. Use them just like other courses to track progress, access quizzes and exams, and share content. Teachers Organize and share selected lessons with your class. Make planning easier by creating your own custom course.

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Gregor Mendel is currently known as the Father of Modern Genetics. This lesson goes through a brief history of his life, workings as a scientist, and his findings. Gregor Mendel Gregor Mendel is known as the Father of Modern Genetics. He is a pretty big name in the science world. However, he did not receive any of this credit while he was alive. We'll come back to this later. Mendel was born in Austria in 1822. His parents were farmers. When he was young and on the farm, Mendel became very interested in plants, trees, and fruit. He was very good at school and soon found himself away from the farm and into schools and religion. Over his lifetime Mendel became a teacher, priest, and scientist. Mendel conducted his now-famous experiments from 1856 to 1863 while he was an Augustinian monk in what is now part of the Czech Republic. Here, he was able to tend to the garden at the monastery. His work was published in 1866.

However, it was not until the 1900s when three scientists, Erich Tschermak, Hugo de Vries, and Carl Correns, rediscovered Mendel's work and confirmed his findings. It was then that Mendel's experiments changed the world of genetics forever. The Experiments Gregor Mendel spent those eight years studying tens of thousands of plants. He mainly studied pea plants because they had distinguished characteristics and they were quick to grow. Mendel would create hybrids from the plants. Hybrids are the blending of two things to make one. An example of a new technology hybrid is an engine that runs on both electricity and gas (two things to make one engine). Mendel's hybrid was two pea plants. He would act as the pollinator, carefully controlling which two plants would create a new generation. While working with the tens of thousands of plants, Mendel would observe the seven different traits from these plants: Flower color - purple or white Flower position - axial or terminal Stem length - short or tall Seed shapes - round or wrinkled Seed color - yellow or green Pod shape - inflated or constricted Pod color - yellow or green Mendel would cross-pollinate the different types of pea plants.

Sometimes the plants would have the same characteristics, and sometimes they would have different characteristics. He would then observe the next generation of plants that were created. He would then pollinate these plants and keep on going. Findings Before and during Mendel's experiments, heredity, the transmission of traits from parents to their offspring, was believed to just be a watered-down blend or combination of traits from the parents to their offspring. However, Mendel's observations from these experiments showed that this was not always the case. Other scientists conducted similar experiments to Gregor Mendel's pea plant experiments. However, their experiments did not last as long, nor were they as extensive as Mendel's. They were not able to observe how sometimes-hidden characteristics would appear after many generations of being absent. While conducting his experiments, Mendel began to see these hidden characteristics make a comeback. They would appear in the offspring of parents who did not show any signs of these traits. This goes against the blending theory.

× Famous Scientists in Genetics: William Bateson Famous Scientists in Genetics: William Bateson written by: alisonc•edited by: Paul Arnold •updated: 2/4/2009 This article summarizes the career of William Bateson, one of the most famous scientists in genetics. In fact he was the person who coined the term "genetics," and carried out important work in the fields of human genetics and plant genetics. slide 1 of 5 Famous Scientist in Genetics Geneticist William Bateson (b. 1861) holds an important place in the history of genetics . He is the first person to have coined the term "genetics" to describe the study of biological inheritance and heredity. He first suggested the term "genetics" in an April,1905 letter to fellow scientist Adam Sedgwick at Cambridge in an effort to persuade him to establish a Chair in the field of heredity. He wrote: "Such a word is badly wanted, and if it were desirable to coin one, 'Genetics' might do." Bateson used the term again at the Third International Conference on Plant Hybridization in London, which took place in 1906.

slide 2 of 5 Early Work Prior to coining the term "genetics," Bateson published a book in 1894 titled "Materials for the Study of Variation" which was based on his study of discontinuous variation as a research student in Cambridge. He undertook plant and animal animal breeding as a means to continue his research in heredity. In 1909, he moved from Cambridge to the John Innes Horticultural Institution to become its first director. Bateson's work was quite successful, as The John Innes Institution soon became a magnet for plant breeders across Europe. Bateson remained director at the Institution until his death in February 1926. slide 3 of 5 Additional Discoveries In 1910, Bateson co-discovered genetic linkage with geneticist Reginald Crundall Punnett, and they both continued their work together as co-founders of the Journal of Genetics. The same year, Bateson also established the term "epistasis" to explain the genetic interaction of two independent traits.

slide 4 of 5 Mendelian Influences and Evolution Bateson is not considered the father of genetics, however - that distinction has been granted to Gregor Johann Mendel (1822 - 1884), an Austrian monk who studied pea plants and their inherited traits. However, Bateson is responsible for popularizing Mendel's work after its rediscovery by Carl Correns, Hugo de Vries, and Eric von Tschermak in 1900. His adherence to Mendel's work placed him in opposition to his former teacher, Walter Raphael Weldon, along with scientist Karl Pearson. The debate was based on the work of Charles Darwin. Bateson was a saltationist, an adherent of the belief that evolutionary changes are sudden and large compared to how organisms normally vary. Saltationists were in opposition to gradualists, who believed in the theory that profound evolutionary change is a slow yet continual process. slide 5 of 5 William Bateson: A Biologist Ahead of His Time: ◄ ● ● ● ● ● ► Pioneers in Genetics This articles series portrays geneticists who have made breakthrough discoveries in the fields of genetics and biotech.

Nirenberg: History Section: Gregor Mendel History Section Acknowledgments Gregor Mendel is usually considered to be the founder of modern genetics. Though farmers had known for centuries that crossbreeding of animals and plants could favor certain desirable traits, Mendel's pea plant experiments conducted between 1856 and 1863 established many of the rules of heredity. An Augustinian monk living in what is now the Czech Republic, Mendel had access to an experimental garden in which he could breed true lines of pea plants and patiently wait for them to crossbreed in specified combinations. He worked with seven characteristics of pea plants: plant height, pod shape and color, seed shape and color, and flower position and color. Using the example of seed color, his results showed that when a yellow pea and a green pea were bred together their offspring plant was always yellow. However, in the next generation of plants, the green peas reappeared at a ratio of 1:3. To explain this phenomenon, Mendel coined the terms recessive and dominant in reference to certain traits.

(In the preceding example, green peas are recessive and yellow peas are dominant.) He published his work in 1866, demonstrating the actions of invisible “factors”—what we now call genes —in providing for visible traits in predictable ways. Mendel never enjoyed recognition in his lifetime. In fact, it was more than three decades later, in 1900, that three scientists doing agricultural research discovered his 1866 paper. Erich Tschermak, Hugo de Vries, and Carl Correns independently verified several of Mendel's experimental findings, and the "age of genetics" was born. In the next several decades, scientists would learn more about genes and the special substance called DNA that carried each living thing's specific traits. Gregor Mendel.

Question: Which Austrian scientist was the founder of genetics?
Answer: (Gregor Johann) Mendel