Query: “As it happens, Zika may also be a good model of the second worrying effect — disease mutation.

Relevant passages:
Genetics <=SEP=> Genetics ( from ancient Greek γένεσις , genesis ) is the study of genes , genetic variation , and heredity in living organisms . It is generally considered a field of biology , but intersects frequently with many other life sciences and is strongly linked with the study of information systems .   The father of genetics is Gregor Mendel , a late 19th-century scientist and Augustinian friar . Mendel studied `` trait inheritance '' , patterns in the way traits are handed down from parents to offspring . He observed that organisms ( pea plants ) inherit traits by way of discrete `` units of inheritance '' . This term , still used today , is a somewhat ambiguous definition of what is referred to as a gene .   Trait inheritance and molecular inheritance mechanisms of genes are still primary principles of genetics in the 21st century , but modern genetics has expanded beyond inheritance to studying the function and behavior of genes . Gene structure and function , variation , and distribution are studied within the context of the cell , the organism ( e.g. dominance ) , and within the context of a population . Genetics has given rise to a number of subfields , including epigenetics and population genetics . Organisms studied within the broad field span the domain of life , including bacteria , plants , animals , and humans .   Genetic processes work in combination with an organism 's environment and experiences to influence development and behavior , often referred to as nature versus nurture . The intracellular or extracellular environment of a cell or organism may switch gene transcription on or off . A classic example is two seeds of genetically identical corn , one placed in a temperate climate and one in an arid climate . While the average height of the two corn stalks may be genetically determined to be equal , the one in the arid climate only grows to half the height of the one in the temperate climate due to lack of water and nutrients in its environment .

Gene <=SEP=> A gene ( from ancient Greek : γόνος , gonos ) is a locus ( or region ) of DNA which is made up of nucleotides and is the molecular unit of heredity . The transmission of genes to an organism 's offspring is the basis of the inheritance of phenotypic traits . These genes make up different DNA sequences called genotypes . Genotypes along with environmental and developmental factors determine what the phenotypes will be . Most biological traits are under the influence of polygenes ( many different genes ) as well as gene -- environment interactions . Some genetic traits are instantly visible , such as eye color or number of limbs , and some are not , such as blood type , risk for specific diseases , or the thousands of basic biochemical processes that comprise life .   Genes can acquire mutations in their sequence , leading to different variants , known as alleles , in the population . These alleles encode slightly different versions of a protein , which cause different phenotypical traits . Usage of the term `` having a gene '' ( e.g. , `` good genes , '' `` hair colour gene '' ) typically refers to containing a different allele of the same , shared gene . Genes evolve due to natural selection or survival of the fittest of the alleles .   The concept of a gene continues to be refined as new phenomena are discovered . For example , regulatory regions of a gene can be far removed from its coding regions , and coding regions can be split into several exons . Some viruses store their genome in RNA instead of DNA and some gene products are functional non-coding RNAs . Therefore , a broad , modern working definition of a gene is any discrete locus of heritable , genomic sequence which affect an organism 's traits by being expressed as a functional product or by regulation of gene expression .

Zika fever <=SEP=> Zika fever , also known as Zika virus disease or simply Zika , is an infectious disease caused by the Zika virus . Most cases have no symptoms , but when present they are usually mild and can resemble dengue fever . Symptoms may include fever , red eyes , joint pain , headache , and a maculopapular rash . Symptoms generally last less than seven days . It has not caused any reported deaths during the initial infection . Mother-to-child transmission during pregnancy can cause microcephaly and other brain malformations in some babies . Infections in adults have been linked to Guillain -- Barré syndrome ( GBS ) .   Zika fever is mainly spread via the bite of mosquitoes of the Aedes type . It can also be sexually transmitted and potentially spread by blood transfusions . Infections in pregnant women can spread to the baby . Diagnosis is by testing the blood , urine , or saliva for the presence of the virus 's RNA when the person is sick , or the blood for antibodies after symptoms are present more than a week .   Prevention involves decreasing mosquito bites in areas where the disease occurs and proper use of condoms . Efforts to prevent bites include the use of insect repellent , covering much of the body with clothing , mosquito nets , and getting rid of standing water where mosquitoes reproduce . There is no effective vaccine . Health officials recommended that women in areas affected by the 2015 -- 16 Zika outbreak consider putting off pregnancy and that pregnant women not travel to these areas . While there is no specific treatment , paracetamol ( acetaminophen ) may help with the symptoms . Admission to hospital is rarely necessary .   The virus that causes the disease was first isolated in Africa in 1947 . The first documented outbreak among people occurred in 2007 in the Federated States of Micronesia . An outbreak started in Brazil in 2015 , and spread to the Americas , Pacific , Asia , and Africa . This led to the World Health Organization declared it a Public Health Emergency of International Concern in February 2016 . The emergency was lifted in November 2016 , but 84 countries still reported cases as of March 2017 .

Mutation <=SEP=> In biology , a mutation is the permanent alteration of the nucleotide sequence of the genome of an organism , virus , or extrachromosomal DNA or other genetic elements .   Mutations result from errors during DNA replication or other types of damage to DNA , which then may undergo error-prone repair ( especially microhomology-mediated end joining ) , or cause an error during other forms of repair , or else may cause an error during replication ( translesion synthesis ) . Mutations may also result from insertion or deletion of segments of DNA due to mobile genetic elements . Mutations may or may not produce discernible changes in the observable characteristics ( phenotype ) of an organism . Mutations play a part in both normal and abnormal biological processes including : evolution , cancer , and the development of the immune system , including junctional diversity .   The genomes of RNA viruses are based on RNA rather than DNA . The RNA viral genome can be double stranded ( as in DNA ) or single stranded . In some of these viruses ( such as the single stranded human immunodeficiency virus ) replication occurs quickly and there are no mechanisms to check the genome for accuracy . This error-prone process often results in mutations .   Mutation can result in many different types of change in sequences . Mutations in genes can either have no effect , alter the product of a gene , or prevent the gene from functioning properly or completely . Mutations can also occur in nongenic regions . One study on genetic variations between different species of Drosophila suggests that , if a mutation changes a protein produced by a gene , the result is likely to be harmful , with an estimated 70 percent of amino acid polymorphisms that have damaging effects , and the remainder being either neutral or marginally beneficial . Due to the damaging effects that mutations can have on genes , organisms have mechanisms such as DNA repair to prevent or correct mutations by reverting the mutated sequence back to its original state .