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The structure of a gene consists of many elements of which the actual protein coding sequence is often only a small part. These include DNA regions that are not transcribed as well as untranslated regions of the RNA.
Firstly, flanking the open reading frame, all genes contain a regulatory sequence that is required for their expression. In order to be expressed, genes require a promoter sequence. The promoter is recognized and bound by transcription factors and RNA polymerase to initiate transcription.:7.1 A gene can have more than one promoter, resulting in messenger RNAs (mRNA) that differ in how far they extend in the 5' end. Promoter regions have a consensus sequence, however highly transcribed genes have "strong" promoter sequences that bind the transcription machinery well, whereas others have "weak" promoters that bind poorly and initiate transcription less frequently.:7.2 Eukaryotic promoter regions are much more complex and difficult to identify than prokaryotic promoters.:7.3
Additionally, genes can have regulatory regions many kilobases upstream or downstream of the open reading frame. These act by binding to transcription factors which then cause the DNA to loop so that the regulatory sequence (and bound transcription factor) become close to the RNA polymerase binding site. For example, enhancers increase transcription by binding an activator protein which then helps to recruit the RNA polymerase to the promoter; conversely silencers bind repressor proteins and make the DNA less available for RNA polymerase.
The transcribed pre-mRNA contains untranslated regions at both ends which contain a ribosome binding site, terminator and start and stop codons. In addition, most eukaryotic open reading frames contain untranslated introns which are removed before the exons are translated. The sequences at the ends of the introns, dictate the splice sites to generate the final mature mRNA which encodes the protein or RNA product.
Many prokaryotic genes are organized into operons, with multiple protein-coding sequences that are transcribed as a unit. The products of operon genes typically have related functions and are involved in the same regulatory network.:7.3
Defining exactly what section of a DNA sequence comprises a gene is difficult. Regulatory regions of a gene such as enhancers do not necessarily have to be close to the coding sequence on the linear molecule because the intervening DNA can be looped out to bring the gene and its regulatory region into proximity. Similarly, a gene's introns can be much larger than its exons. Regulatory regions can even be on entirely different chromosomes and operate in trans to allow regulatory regions on one chromosome to come in contact with target genes on another chromosome.
Early work in molecular genetics suggested the model that one gene makes one protein. This model has been refined since the discovery of genes that can encode multiple proteins by alternative splicing and coding sequences split in short section across the genome whose mRNAs are concatenated by trans-splicing.
A broad operational definition is sometimes used to encompass the complexity of these diverse phenomena, where a gene is defined as a union of genomic sequences encoding a coherent set of potentially overlapping functional products. This definition categorizes genes by their functional products (proteins or RNA) rather than their specific DNA loci, with regulatory elements classified as gene-associated regions.
In all organisms, two steps are required to read the information encoded in a gene's DNA and produce the protein it specifies. First, the gene's DNA is transcribed to messenger RNA (mRNA).:6.1 Second, that mRNA is translated to protein.:6.2 RNA-coding genes must still go through the first step, but are not translated into protein. The process of producing a biologically functional molecule of either RNA or protein is called gene expression, and the resulting molecule is called a gene product.
The nucleotide sequence of a gene's DNA specifies the amino acid sequence of a protein through the genetic code. Sets of three nucleotides, known as codons, each correspond to a specific amino acid.:6 Additionally, a "start codon", and three "stop codons" indicate the beginning and end of the protein coding region. There are 64 possible codons (four possible nucleotides at each of three positions, hence 43 possible codons) and only 20 standard amino acids; hence the code is redundant and multiple codons can specify the same amino acid. The correspondence between codons and amino acids is nearly universal among all known living organisms.
Transcription produces a single-stranded RNA molecule known as messenger RNA, whose nucleotide sequence is complementary to the DNA from which it was transcribed.:6.1 The mRNA acts as an intermediate between the DNA gene and its final protein product. The gene's DNA is used as a template to generate a complementary mRNA. The mRNA matches the sequence of the gene's DNA coding strand because it is synthesised as the complement of the template strand. Transcription is performed by an enzyme called an RNA polymerase, which reads the template strand in the 3' to 5' direction and synthesizes the RNA from 5' to 3'. To initiate transcription, the polymerase first recognizes and binds a promoter region of the gene. Thus, a major mechanism of gene regulation is the blocking or sequestering the promoter region, either by tight binding by repressor molecules that physically block the polymerase, or by organizing the DNA so that the promoter region is not accessible.:7
In prokaryotes, transcription occurs in the cytoplasm; for very long transcripts, translation may begin at the 5' end of the RNA while the 3' end is still being transcribed. In eukaryotes, transcription occurs in the nucleus, where the cell's DNA is stored. The RNA molecule produced by the polymerase is known as the primary transcript and undergoes post-transcriptional modifications before being exported to the cytoplasm for translation. One of the modifications performed is the splicing of introns which are sequences in the transcribed region that do not encode protein. Alternative splicing mechanisms can result in mature transcripts from the same gene having different sequences and thus coding for different proteins. This is a major form of regulation in eukaryotic cells and also occurs in some prokaryotes.:7.5
Translation is the process by which a mature mRNA molecule is used as a template for synthesizing a new protein.:6.2 Translation is carried out by ribosomes, large complexes of RNA and protein responsible for carrying out the chemical reactions to add new amino acids to a growing polypeptide chain by the formation of peptide bonds. The genetic code is read three nucleotides at a time, in units called codons, via interactions with specialized RNA molecules called transfer RNA (tRNA). Each tRNA has three unpaired bases known as the anticodon that are complementary to the codon it reads on the mRNA. The tRNA is also covalently attached to the amino acid specified by the complementary codon. When the tRNA binds to its complementary codon in an mRNA strand, the ribosome attaches its amino acid cargo to the new polypeptide chain, which is synthesized from amino terminus to carboxyl terminus. During and after synthesis, most new proteins must folds to their active three-dimensional structure before they can carry out their cellular functions.:3
Genes are regulated so that they are expressed only when the product is needed, since expression draws on limited resources.:7 A cell regulates its gene expression depending on its external environment (e.g. available nutrients, temperature and other stresses), its internal environment (e.g. cell division cycle, metabolism, infection status), and its specific role if in a multicellular organism. Gene expression can be regulated at any step: from transcriptional initiation, to RNA processing, to post-translational modification of the protein. The regulation of lactose metabolism genes in E. coli (lac operon) was the first such mechanism to be described in 1961.
A typical protein-coding gene is first copied into RNA as an intermediate in the manufacture of the final protein product.:6.1 In other cases, the RNA molecules are the actual functional products, as in the synthesis of ribosomal RNA and transfer RNA. Some RNAs known as ribozymes are capable of enzymatic function, and microRNA has a regulatory role. The DNA sequences from which such RNAs are transcribed are known as non-coding RNA genes.
Some viruses store their entire genomes in the form of RNA, and contain no DNA at all. Because they use RNA to store genes, their cellular hosts may synthesize their proteins as soon as they are infected and without the delay in waiting for transcription. On the other hand, RNA retroviruses, such as HIV, require the reverse transcription of their genome from RNA into DNA before their proteins can be synthesized. RNA-mediated epigenetic inheritance has also been observed in plants and very rarely in animals.
Organisms inherit their genes from their parents. Asexual organisms simply inherit a complete copy of their parent's genome. Sexual organisms have two copies of each chromosome because they inherit one complete set from each parent.:1
According to Mendelian inheritance, variations in an organism's phenotype (observable physical and behavioral characteristics) are due in part to variations in its genotype (particular set of genes). Each gene specifies a particular trait with different sequence of a gene (alleles) giving rise to different phenotypes. Most eukaryotic organisms (such as the pea plants Mendel worked on) have two alleles for each trait, one inherited from each parent.:20
Alleles at a locus may be dominant or recessive; dominant alleles give rise to their corresponding phenotypes when paired with any other allele for the same trait, whereas recessive alleles give rise to their corresponding phenotype only when paired with another copy of the same allele. For example, if the allele specifying tall stems in pea plants is dominant over the allele specifying short stems, then pea plants that inherit one tall allele from one parent and one short allele from the other parent will also have tall stems. Mendel's work demonstrated that alleles assort independently in the production of gametes, or germ cells, ensuring variation in the next generation. Although Mendelian inheritance remains a good model for many traits determined by single genes (including a number of well-known genetic disorders) it does not include the physical processes of DNA replication and cell division.
The growth, development, and reproduction of organisms relies on cell division, or the process by which a single cell divides into two usually identical daughter cells. This requires first making a duplicate copy of every gene in the genome in a process called DNA replication.:5.2 The copies are made by specialized enzymes known as DNA polymerases, which "read" one strand of the double-helical DNA, known as the template strand, and synthesize a new complementary strand. Because the DNA double helix is held together by base pairing, the sequence of one strand completely specifies the sequence of its complement; hence only one strand needs to be read by the enzyme to produce a faithful copy. The process of DNA replication is semiconservative; that is, the copy of the genome inherited by each daughter cell contains one original and one newly synthesized strand of DNA.:5.2
After DNA replication is complete, the cell must physically separate the two copies of the genome and divide into two distinct membrane-bound cells.:18.2 In prokaryotes (bacteria and archaea) this usually occurs via a relatively simple process called binary fission, in which each circular genome attaches to the cell membrane and is separated into the daughter cells as the membrane invaginates to split the cytoplasm into two membrane-bound portions. Binary fission is extremely fast compared to the rates of cell division in eukaryotes. Eukaryotic cell division is a more complex process known as the cell cycle; DNA replication occurs during a phase of this cycle known as S phase, whereas the process of segregating chromosomes and splitting the cytoplasm occurs during M phase.:18.1
The duplication and transmission of genetic material from one generation of cells to the next is the basis for molecular inheritance, and the link between the classical and molecular pictures of genes. Organisms inherit the characteristics of their parents because the cells of the offspring contain copies of the genes in their parents' cells. In asexually reproducing organisms, the offspring will be a genetic copy or clone of the parent organism. In sexually reproducing organisms, a specialized form of cell division called meiosis produces cells called gametes or germ cells that are haploid, or contain only one copy of each gene.:20.2 The gametes produced by females are called eggs or ova, and those produced by males are called sperm. Two gametes fuse to form a diploid fertilized egg, a single cell that has two sets of genes, with one copy of each gene from the mother and one from the father.:20
During the process of meiotic cell division, an event called genetic recombination or crossing-over can sometimes occur, in which a length of DNA on one chromatid is swapped with a length of DNA on the corresponding sister chromatid. This has no effect if the alleles on the chromatids are the same, but results in reassortment of otherwise linked alleles if they are different.:5.5 The Mendelian principle of independent assortment asserts that each of a parent's two genes for each trait will sort independently into gametes; which allele an organism inherits for one trait is unrelated to which allele it inherits for another trait. This is in fact only true for genes that do not reside on the same chromosome, or are located very far from one another on the same chromosome. The closer two genes lie on the same chromosome, the more closely they will be associated in gametes and the more often they will appear together; genes that are very close are essentially never separated because it is extremely unlikely that a crossover point will occur between them. This is known as genetic linkage.
DNA replication is for the most part extremely accurate, however errors (mutations) do occur.:7.6 The error rate in eukaryotic cells can be as low as 10−8 per nucleotide per replication, whereas for some RNA viruses it can be as high as 10−3. This means that each generation, each human genome accumulates 1–2 new mutations. Small mutations can be caused by DNA replication and the aftermath of DNA damage and include point mutations in which a single base is altered and frameshift mutations in which a single base is inserted or deleted. Either of these mutations can change the gene by missense (change a codon to encode a different amino acid) or nonsense (a premature stop codon). Larger mutations can be caused by errors in recombination to cause chromosomal abnormalities including the duplication, deletion, rearrangement or inversion of large sections of a chromosome. Additionally, the DNA repair mechanisms that normally revert mutations can introduce errors when repairing the physical damage to the molecule is more important than restoring an exact copy, for example when repairing double-strand breaks.:5.4
When multiple different alleles for a gene are present in a species's population it is called polymorphic. Most different alleles are functionally equivalent, however some alleles can give rise to different phenotypic traits. A gene's most common allele is called the wild type, and rare alleles are called mutants. The genetic variation in relative frequencies of different alleles in a population is due to both natural selection and genetic drift. The wild-type allele is not necessarily the ancestor of less common alleles, nor is it necessarily fitter.
Most mutations within genes are neutral, having no effect on the organism's phenotype (silent mutations). Some mutations do not change the amino acid sequence because multiple codons encode the same amino acid (synonymous mutations). Other mutations can be neutral if they lead to amino acid sequence changes, but the protein still functions similarly with the new amino acid (e.g. conservative mutations). Many mutations, however, are deleterious or even lethal, and are removed from populations by natural selection. Genetic disorders are the result of deleterious mutations and can be due to spontaneous mutation in the affected individual, or can be inherited. Finally, a small fraction of mutations are beneficial, improving the organism's fitness and are extremely important for evolution, since their directional selection leads to adaptive evolution.:7.6
Genes with a most recent common ancestor, and thus a shared evolutionary ancestry, are known as homologs. These genes appear either from gene duplication within an organism's genome, where they are known as paralogous genes, or are the result of divergence of the genes after a speciation event, where they are known as orthologous genes,:7.6 and often perform the same or similar functions in related organisms. It is often assumed that the functions of orthologous genes are more similar than those of paralogous genes, although the difference is minimal.
The relationship between genes can be measured by comparing the sequence alignment of their DNA.:7.6 The degree of sequence similarity between homologous genes is called conserved sequence. Most changes to a gene's sequence do not affect its function and so genes accumulate mutations over time by neutral molecular evolution. Additionally, any selection on a gene will cause its sequence to diverge at a different rate. Genes under stabilizing selection are constrained and so change more slowly whereas genes under directional selection change sequence more rapidly. The sequence differences between genes can be used for phylogenetic analyses to study how those genes have evolved and how the organisms they come from are related.
The most common source of new genes in eukaryotic lineages is gene duplication, which creates copy number variation of an existing gene in the genome. The resulting genes (paralogs) may then diverge in sequence and in function. Sets of genes formed in this way comprise a gene family. Gene duplications and losses within a family are common and represent a major source of evolutionary biodiversity. Sometimes, gene duplication may result in a nonfunctional copy of a gene, or a functional copy may be subject to mutations that result in loss of function; such nonfunctional genes are called pseudogenes.:7.6
De novo or "orphan" genes, whose sequence shows no similarity to existing genes, are extremely rare. Estimates of the number of de novo genes in the human genome range from 18 to 60. Such genes are typically shorter and simpler in structure than most eukaryotic genes, with few if any introns. Two primary sources of orphan protein-coding genes are gene duplication followed by extremely rapid sequence change, such that the original relationship is undetectable by sequence comparisons, and formation through mutation of "cryptic" transcription start sites that introduce a new open reading frame in a region of the genome that did not previously code for a protein.
Horizontal gene transfer refers to the transfer of genetic material through a mechanism other than reproduction. This mechanism is a common source of new genes in prokaryotes, sometimes thought to contribute more to genetic variation than gene duplication. It is a common means of spreading antibiotic resistance, virulence, and adaptive metabolic functions. Although horizontal gene transfer is rare in eukaryotes, likely examples have been identified of protist and alga genomes containing genes of bacterial origin.
The genome size, and the number of genes it encodes varies widely between organisms. The smallest genomes occur in viruses (which can have as few as 2 protein-coding genes), and viroids (which act as a single non-coding RNA gene). Conversely, plants can have extremely large genomes, with rice containing >46,000 protein-coding genes. The total number of protein-coding genes (the Earth's proteome) is estimated to be 5 million sequences.
Although the number of base-pairs of DNA in the human genome has been known since the 1960s, the estimated number of genes has changed over time as definitions of genes, and methods of detecting them have been refined. Initial theoretical predictions of the number of human genes were as high as 2,000,000. Early experimental measures indicated there to be 50,000–100,000 transcribed genes (expressed sequence tags). Subsequently, the sequencing in the Human Genome Project indicated that many of these transcripts were alternative variants of the same genes, and the total number of protein-coding genes was revised down to ~20,000 with 13 genes encoded on the mitochondrial genome. Of the human genome, only 1–2% consists of protein-coding genes, with the remainder being 'noncoding' DNA such as introns, retrotransposons, and noncoding RNAs.
Essential genes are the set of genes thought to be critical for an organism's survival. This definition assumes the abundant availability of all relevant nutrients and the absence of environmental stress. Only a small portion of an organism's genes are essential. In bacteria, an estimated 250–400 genes are essential for Escherichia coli and Bacillus subtilis, which is less than 10% of their genes. Half of these genes are orthologs in both organisms and are largely involved in protein synthesis. In the budding yeast Saccharomyces cerevisiae the number of essential genes is slightly higher, at 1000 genes (~20% of their genes). Although the number is more difficult to measure in higher eukaryotes, mice and humans are estimated to have around 2000 essential genes (~10% of their genes).
Housekeeping genes are critical for carrying out basic cell functions and so are expressed at a relatively constant level (constitutively). Since their expression is constant, housekeeping genes are used as experimental controls when analysing gene expression. Not all essential genes are housekeeping genes since some essential genes are developmentally regulated or expressed at certain times during the organism's life cycle.
Gene nomenclature has been established by the HUGO Gene Nomenclature Committee (HGNC) for each known human gene in the form of an approved gene name and symbol (short-form abbreviation), which can be accessed through a database maintained by HGNC. Symbols are chosen to be unique, and each gene has only one symbol (although approved symbols sometimes change). Symbols are preferably kept consistent with other members of a gene family and with homologs in other species, particularly the mouse due to its role as a common model organism.
Genetic engineering is the modification of an organism's genome through biotechnology. Since the 1970s, a variety of techniques have been developed to specifically add, remove and edit genes in an organism. Recently developed genome engineering techniques use engineered nuclease enzymes to create targeted DNA repair in a chromosome to either disrupt or edit a gene when the break is repaired. The related term synthetic biology is sometimes used to refer to extensive genetic engineering of an organism.
Genetic engineering is now a routine research tool with model organisms. For example, genes are easily added to bacteria and lineages of knockout mice with a specific gene's function disrupted are used to investigate that gene's function. Many organisms have been genetically modified for applications in agriculture, industrial biotechnology, and medicine.
For multicellular organisms, typically the embryo is engineered which grows into the adult genetically modified organism. However, the genomes of cells in an adult organism can be edited using gene therapy techniques to treat genetic diseases.
Guinea-Bissau (i/ˈɡɪni bɪˈsaʊ/, GI-nee-bi-SOW), officially the Republic of Guinea-Bissau (Portuguese: República da Guiné-Bissau, pronounced: [ʁeˈpublikɐ dɐ ɡiˈnɛ biˈsaw]), is a country in West Africa. It covers 36,125 square kilometres (13,948 sq mi) with an estimated population of 1,704,000.
Guinea-Bissau was once part of the kingdom of Gabu, as well as part of the Mali Empire. Parts of this kingdom persisted until the 18th century, while a few others were under some rule by the Portuguese Empire since the 16th century. In the 19th century, it was colonized as Portuguese Guinea. Upon independence, declared in 1973 and recognised in 1974, the name of its capital, Bissau, was added to the country's name to prevent confusion with Guinea (formerly French Guinea). Guinea-Bissau has a history of political instability since independence, and no elected president has successfully served a full five-year term.
Only 14% of the population speaks Portuguese, established as the official language in the colonial period. Almost half the population (44%) speaks Crioulo, a Portuguese-based creole language, and the remainder speak a variety of native African languages. The main religions are African traditional religions and Islam; there is a Christian (mostly Roman Catholic) minority. The country's per-capita gross domestic product is one of the lowest in the world.
Guinea-Bissau is a member of the United Nations, African Union, Economic Community of West African States, Organisation of Islamic Cooperation, the Latin Union, Community of Portuguese Language Countries, La Francophonie and the South Atlantic Peace and Cooperation Zone.
Guinea-Bissau was once part of the kingdom of Gabu, part of the Mali Empire; parts of this kingdom persisted until the 18th century. Other parts of the territory in the current country were considered by the Portuguese as part of their empire. Portuguese Guinea was known as the Slave Coast, as it was a major area for the exportation of African slaves by Europeans to the western hemisphere. Previously slaves had been traded by Arabs north to the northern part of Africa and into the Middle East.
Early reports of Europeans reaching this area include those of the Venetian Alvise Cadamosto's voyage of 1455, the 1479–1480 voyage by Flemish-French trader Eustache de la Fosse, and Diogo Cão. In the 1480s this Portuguese explorer reached the Congo River and the lands of Bakongo, setting up the foundations of modern Angola, some 4200 km down the African coast from Guinea-Bissau.
Although the rivers and coast of this area were among the first places colonized by the Portuguese, who set up trading posts in the 16th century, they did not explore the interior until the 19th century. The local African rulers in Guinea, some of whom prospered greatly from the slave trade, controlled the inland trade and did not allow the Europeans into the interior. They kept them in the fortified coastal settlements where the trading took place. African communities that fought back against slave traders also distrusted European adventurers and would-be settlers. The Portuguese in Guinea were largely restricted to the port of Bissau and Cacheu. A small number of European settlers established isolated farms along Bissau's inland rivers.
For a brief period in the 1790s, the British tried to establish a rival foothold on an offshore island, at Bolama. But by the 19th century the Portuguese were sufficiently secure in Bissau to regard the neighbouring coastline as their own special territory, also up north in part of present South Senegal.
An armed rebellion beginning in 1956 by the African Party for the Independence of Guinea and Cape Verde (PAIGC) under the leadership of Amílcar Cabral gradually consolidated its hold on then Portuguese Guinea. Unlike guerrilla movements in other Portuguese colonies, the PAIGC rapidly extended its military control over large portions of the territory, aided by the jungle-like terrain, its easily reached borderlines with neighbouring allies, and large quantities of arms from Cuba, China, the Soviet Union, and left-leaning African countries. Cuba also agreed to supply artillery experts, doctors, and technicians. The PAIGC even managed to acquire a significant anti-aircraft capability in order to defend itself against aerial attack. By 1973, the PAIGC was in control of many parts of Guinea, although the movement suffered a setback in January 1973 when Cabral was assassinated.
Independence was unilaterally declared on 24 September 1973. Recognition became universal following the 25 April 1974 socialist-inspired military coup in Portugal, which overthrew Lisbon's Estado Novo regime.
Luís Cabral, brother of Amílcar and co-founder of PAIGC, was appointed the first President of Guinea-Bissau. Following independence, the PAIGC killed thousands of local Guinean soldiers who had fought along with the Portuguese Army against guerrillas. Some escaped to settle in Portugal or other African nations. One of the massacres occurred in the town of Bissorã. In 1980 the PAIGC acknowledged in its newspaper Nó Pintcha (dated 29 November 1980) that many Gueinean soldiers had been executed and buried in unmarked collective graves in the woods of Cumerá, Portogole, and Mansabá.
The country was controlled by a revolutionary council until 1984. The first multi-party elections were held in 1994. An army uprising in May 1998 led to the Guinea-Bissau Civil War and the president's ousting in June 1999. Elections were held again in 2000, and Kumba Ialá was elected president.
In September 2003, a military coup was conducted. The military arrested Ialá on the charge of being "unable to solve the problems". After being delayed several times, legislative elections were held in March 2004. A mutiny of military factions in October 2004 resulted in the death of the head of the armed forces and caused widespread unrest.
In June 2005, presidential elections were held for the first time since the coup that deposed Ialá. Ialá returned as the candidate for the PRS, claiming to be the legitimate president of the country, but the election was won by former president João Bernardo Vieira, deposed in the 1999 coup. Vieira beat Malam Bacai Sanhá in a runoff election. Sanhá initially refused to concede, claiming that tampering and electoral fraud occurred in two constituencies including the capital, Bissau.
Despite reports of arms entering the country prior to the election and some "disturbances during campaigning," including attacks on government offices by unidentified gunmen, foreign election monitors described the 2005 election overall as "calm and organized".
Three years later, PAIGC won a strong parliamentary majority, with 67 of 100 seats, in the parliamentary election held in November 2008. In November 2008, President Vieira's official residence was attacked by members of the armed forces, killing a guard but leaving the president unharmed.
On 2 March 2009, however, Vieira was assassinated by what preliminary reports indicated to be a group of soldiers avenging the death of the head of joint chiefs of staff, General Batista Tagme Na Wai. Tagme died in an explosion on Sunday, 1 March 2009, target of an assassination. Military leaders in the country pledged to respect the constitutional order of succession. National Assembly Speaker Raimundo Pereira was appointed as an interim president until a nationwide election on 28 June 2009. It was won by Malam Bacai Sanhá.
On the evening of 12 April 2012, members of the country's military staged a coup d'état and arrested the interim president and a leading presidential candidate. Former vice chief of staff, General Mamadu Ture Kuruma, assumed control of the country in the transitional period and started negotiations with opposition parties.
Guinea-Bissau is a republic. In the past, the government had been highly centralized. Multi-party governance was not established until mid-1991. The president is the head of state and the prime minister is the head of government. Since 1974, no president has successfully served a full five-year term.
At the legislative level, a unicameral Assembleia Nacional Popular (National People's Assembly) is made up of 100 members. They are popularly elected from multi-member constituencies to serve a four-year term. The judicial system is headed by a Tribunal Supremo da Justiça (Supreme Court), made up of nine justices appointed by the president; they serve at the pleasure of the president.
João Bernardo "Nino" Vieira was elected in 2005 as President of Guinea-Bissau as an independent, being declared winner of the second round by the CNE (Comité Nacional de Eleições). Vieira returned to power in 2005 six years after being ousted from office during a civil war. Previously, he held power for 19 years after taking power in 1980 in a bloodless coup. In that action, he toppled the government of Luís Cabral.
He was killed on 2 March 2009, possibly by soldiers in retaliation for the assassination of General Batista Tagme Na Waie, the head of the joint chiefs of staff, killed in an explosion. Vieira's death did not trigger widespread violence, but there were signs of turmoil in the country, according to the advocacy group Swisspeace. Malam Bacai Sanhá was elected after a transition. In the 2009 election to replace the assassinated Vieira, Sanhá was the presidential candidate of the PAIGC while Kumba Ialá was the presidential candidate of the PRS.
In 2012, President Rachide Sambu-balde Malam Bacai Sanhá died. He belonged to PAIGC (African Party for the Independence of Guinea and Cape Verde), one of the two major political parties in Guinea-Bissau, along with the PRS (Party for Social Renewal). There are more than 20 minor parties.
Guinea-Bissau is divided into eight regions (regiões) and one autonomous sector (sector autónomo). These, in turn, are subdivided into 37 Sectors. The regions are:
Guinea-Bissau is bordered by Senegal to the north and Guinea to the south and east, with the Atlantic Ocean to its west. It lies mostly between latitudes 11° and 13°N (a small area is south of 11°), and longitudes 13° and 17°W.
At 36,125 square kilometres (13,948 sq mi), the country is larger in size than Taiwan or Belgium. It lies at a low altitude; its highest point is 300 metres (984 ft). The terrain of is mostly low coastal plain with swamps of Guinean mangroves rising to Guinean forest-savanna mosaic in the east. Its monsoon-like rainy season alternates with periods of hot, dry harmattan winds blowing from the Sahara. The Bijagos Archipelago lies off of the mainland.
Guinea-Bissau is warm all year around and there is little temperature fluctuation; it averages 26.3 °C (79.3 °F). The average rainfall for Bissau is 2,024 millimetres (79.7 in) although this is almost entirely accounted for during the rainy season which falls between June and September/October. From December through April, the country experiences drought.
Guinea-Bissau's GDP per capita is one of the lowest in the world, and its Human Development Index is one of the lowest on earth. More than two-thirds of the population lives below the poverty line. The economy depends mainly on agriculture; fish, cashew nuts and ground nuts are its major exports.
A long period of political instability has resulted in depressed economic activity, deteriorating social conditions, and increased macroeconomic imbalances. It takes longer on average to register a new business in Guinea-Bissau (233 days or about 33 weeks) than in any other country in the world except Suriname. [The Economist, Pocket World in Figures, 2008 Edition, London: Profile Books]
Guinea-Bissau has started to show some economic advances after a pact of stability was signed by the main political parties of the country, leading to an IMF-backed structural reform program. The key challenges for the country in the period ahead are to achieve fiscal discipline, rebuild public administration, improve the economic climate for private investment, and promote economic diversification. After the country became independent from Portugal in 1974 due to the Portuguese Colonial War and the Carnation Revolution, the rapid exodus of the Portuguese civilian, military, and political authorities resulted in considerable damage to the country's economic infrastructure, social order, and standard of living.
After several years of economic downturn and political instability, in 1997, Guinea-Bissau entered the CFA franc monetary system, bringing about some internal monetary stability. The civil war that took place in 1998 and 1999, and a military coup in September 2003 again disrupted economic activity, leaving a substantial part of the economic and social infrastructure in ruins and intensifying the already widespread poverty. Following the parliamentary elections in March 2004 and presidential elections in July 2005, the country is trying to recover from the long period of instability, despite a still-fragile political situation.
Beginning around 2005, drug traffickers based in Latin America began to use Guinea-Bissau, along with several neighboring West African nations, as a transshipment point to Europe for cocaine. The nation was described by a United Nations official as being at risk for becoming a "narco-state". The government and the military have done little to stop drug trafficking, which increased after the 2012 coup d'état.
According to the 2010 revison of the UN World Population Prospects, Guinea-Bissau's population was 1,515,000 in 2010, compared to 518,000 in 1950. The proportion of the population below the age of 15 in 2010 was 41.3%, 55.4% were aged between 15 and 65 years of age, while 3.3% were aged 65 years or older.
Portuguese natives comprise a very small percentage of Guinea-Bissauans. After Guinea-Bissau gained independence, most of the Portuguese nationals left the country. The country has a tiny Chinese population. These include traders and merchants of mixed Portuguese and Chinese ancestry from Macau, a former Asian Portuguese colony.
14% of the population speaks the official language Portuguese, the language of government and national communication during centuries of colonial rule. 44% speak Kriol, a Portuguese-based creole language, which is effectively a national language of communication among groups. The remainder speak a variety of native African languages unique to ethnicities.
Most Portuguese and Mestiços speak one of the African languages and Kriol as second languages. French is also taught in schools because Guinea-Bissau is surrounded by French-speaking nations. Guinea-Bissau is a full member of the Francophonie.
Throughout the 20th century, most Bissau-Guineans practiced some form of Animism. In the early 21st century, many have adopted Islam, which is now practiced by 50% of the country's population. Most of Guinea-Bissau's Muslims are of the Sunni denomination with approximately 2% belonging to the Ahmadiyya sect.
Approximately 10% of the country's population belong to the Christian community, and 40% continue to hold Indigenous beliefs. These statistics can be misleading, however, as many residents practice syncretic forms of Islamic and Christian faiths, combining their practices with traditional African beliefs.
The prevalence of HIV-infection among the adult population is 1.8%. Only 20% of infected pregnant women receive anti retroviral coverage to prevent transmission to newborns.
Malaria kills more residents; 9% of the population have reported infection, It causes three times as many deaths as AIDS. In 2008, fewer than half of children younger than five slept under antimalaria nets or had access to antimalarial drugs.
Despite lowering rates in surrounding countries, cholera rates were reported in November 2012 to be on the rise, with 1,500 cases reported and nine deaths. A 2008 cholera epidemic in Guinea-Bissau affected 14,222 people and killed 225.
The 2010 maternal mortality rate per 100,000 births for Guinea Bissau was 1000. This compares with 804.3 in 2008 and 966 in 1990. The under 5 mortality rate, per 1,000 births, was 195 and the neonatal mortality as a percentage of under 5's mortality was 24. The number of midwives per 1,000 live births was 3; one out of eighteen pregnant women die as a result of pregnancy. According to a 2013 UNICEF report, 50% of women in Guinea Bissau had undergone female genital mutilation. In 2010, Guinea Bissau had the 7th highest maternal mortality rate in the world.
Education is compulsory from the age of 7 to 13. The enrollment of boys is higher than that of girls. In 1998, the gross primary enrollment rate was 53.5%, with higher enrollment ratio for males (67.7%) compared to females (40%).
Guinea-Bissau has several secondary schools (general as well as technical) and a number of universities, to which an institutionally autonomous Faculty of Law as well as a Faculty of Medicine have been added.
The music of Guinea-Bissau is usually associated with the polyrhythmic gumbe genre, the country's primary musical export. However, civil unrest and other factors have combined over the years to keep gumbe, and other genres, out of mainstream audiences, even in generally syncretist African countries.
The calabash is the primary musical instrument of Guinea-Bissau, and is used in extremely swift and rhythmically complex dance music. Lyrics are almost always in Guinea-Bissau Creole, a Portuguese-based creole language, and are often humorous and topical, revolving around current events and controversies, especially AIDS.
The word gumbe is sometimes used generically, to refer to any music of the country, although it most specifically refers to a unique style that fuses about ten of the country's folk music traditions. Tina and tinga are other popular genres, while extent folk traditions include ceremonial music used in funerals, initiations and other rituals, as well as Balanta brosca and kussundé, Mandinga djambadon, and the kundere sound of the Bissagos Islands.
Rice is a staple in the diet of residents near the coast and millet a staple in the interior. Fish, shellfish, fruits and vegetables are commonly eaten along with cereal grains, milk, curd and whey. The Portuguese encouraged peanut production. Vigna subterranea (Bambara groundnut) and Macrotyloma geocarpum (Hausa groundnut) are also grown. Black-eyed peas are also part of the diet. Palm oil is harvested.
Common dishes include soups and stews. Common ingredients include yams, sweet potato, cassava, onion, tomato and plantain. Spices, peppers and chilis are used in cooking, including Aframomum melegueta seeds (Guinea pepper).
Flora Gomes is an internationally renowned film director; his most famous film is Nha Fala (English: My Voice). Gomes's Mortu Nega (Death Denied) (1988) was the first fiction film and the second feature film ever made in Guinea-Bissau. (The first feature film was N’tturudu, by director Umban u’Kest in 1987.) At FESPACO 1989, Mortu Nega won the prestigious Oumarou Ganda Prize. Mortu Nega is in Creole with English subtitles. In 1992, Gomes directed Udju Azul di Yonta, which was screened in the Un Certain Regard section at the 1992 Cannes Film Festival. Gomes has also served on the boards of many Africa-centric film festivals.
This article covers numbered east-west streets in Manhattan, New York City. Major streets have their own linked articles; minor streets are discussed here. The streets do not run exactly east–west, because the grid plan is aligned with the Hudson River rather than with the cardinal directions. "West" is approximately 29 degrees north of true west.
The numbered streets carry crosstown traffic. In general, even-numbered streets are one-way eastbound and odd-numbered streets are one-way west. Several exceptions reverse this. Most wider streets carry two-way traffic, as do a few of the narrow ones.
Streets' names change from West to East (for instance, East 10th Street to West 10th Street) at Broadway below 8th Street, and at Fifth Avenue from 8th Street and above.
Although the numbered streets begin just north of East Houston Street in the East Village, they generally do not extend west into Greenwich Village, which already had streets when the grid plan was laid out by the Commissioners' Plan of 1811. Streets that do continue farther west change direction before reaching the Hudson River. The grid covers the length of the island from 14th Street north.
220th Street is the highest numbered street on Manhattan Island. Marble Hill is also within the borough of Manhattan, so the highest street number in the borough is 228th Street. However, the numbering continues in the Bronx up to 263rd Street. The lowest number is East First Street—which runs in Alphabet City near East Houston Street—as well as First Place in Battery Park City.
East 1st Street begins just North of East Houston Street at Avenue A and continues to Bowery. Peretz Square, a small triangular sliver park where Houston Street, First Street and First Avenue meet marks the spot where the grid takes hold.
East 2nd Street begins just North of East Houston Street at Avenue C and also continues to Bowery. The East end of East 3rd, 4th, 5th, and 7th Streets is Avenue D, with East 6th Street continuing further Eastward and connecting to FDR Drive.
The west end of these streets is Bowery and Third Avenue, except for 3rd Street (formerly Amity Place; to Sixth Avenue) and 4th Street (to 13th Street), which extend west and north, respectively, into Greenwich Village. Great Jones Street connects East 3rd to West 3rd.
East 5th Street goes west to Cooper Square, but is interrupted between Avenues B and C by The Earth School, Public School 364, and between First Avenue and Avenue A by the Village View Apartments.
8th and 9th Streets run parallel to each other, beginning at Avenue D, interrupted by Tompkins Square Park at Avenue B, resuming at Avenue A and continuing to Sixth Avenue. West 8th Street is an important local shopping street. 8th Street between Avenue A and Third Avenue is called St Mark's Place, but it is counted in the length below.
10th Street (40°44′03″N 74°00′11″W / 40.7342580°N 74.0029670°W / 40.7342580; -74.0029670) begins at the FDR Drive and Avenue C. West of Sixth Avenue, it turns southward about 40 degrees to join the Greenwich Village street grid and continue to West Street on the Hudson River. Because West 4th Street turns northward at Sixth Avenue, it intersects 10th, 11th and 12th and 13th Streets in the West Village. The M8 bus operates on 10th Street in both directions between Avenue D and Avenue A, and eastbound between West Street and Sixth Avenue. 10th Street has an eastbound bike lane from West Street to the East River. In 2009, the two-way section of 10th Street between Avenue A and the East River had bicycle markings and sharrows installed, but it still has no dedicated bike lane. West 10th Street was previously named Amos Street for Richard Amos. The end of West 10th Street toward the Hudson River was once the home of Newgate Prison, New York City's first prison and the United States' second.

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