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The study of human genetic variation has evolutionary significance and medical applications. It can help scientists reconstruct and understand patterns of past human migration. In medicine, study of human genetic variation may be important because some disease-causing alleles occur more often in certain population groups.
Immune genes; 417 genes involved in the immune system showed strong evidence of adaptive evolution in the study of Nielsen et al. (2005a). This is probably because the immune genes may become involved in an evolutionary arms race with bacteria and viruses (Daugherty and Malik 2012; Van der Lee et al. 2017). These pathogens evolve very rapidly ...
A gene can acquire mutations in its sequence, leading to different variants, known as alleles, in the population. These alleles encode slightly different versions of a gene, which may cause different phenotypical traits. [4] Genes evolve due to natural selection or survival of the fittest and genetic drift of the alleles.
Gene loss could thus be a common mechanism of evolutionary adaptation (the "less-is-more" hypothesis). [17] 80 genes were lost in the human lineage after separation from the last common ancestor with the chimpanzee. 36 of those were for olfactory receptors. Genes involved in chemoreception and immune response are overrepresented. [18]
However, since there are many genes that can vary to cause genetic disorders, in aggregate they constitute a significant component of known medical conditions, especially in pediatric medicine. Molecularly characterized genetic disorders are those for which the underlying causal gene has been identified.
Genetic variation is the difference in DNA among individuals [1] or the differences between populations among the same species. [2] The multiple sources of genetic variation include mutation and genetic recombination. [3] Mutations are the ultimate sources of genetic variation, but other mechanisms, such as genetic drift, contribute to it, as ...
The human genome is the total collection of genes in a human being contained in the human chromosome, composed of over three billion nucleotides. [2] In April 2003, the Human Genome Project was able to sequence all the DNA in the human genome, and to discover that the human genome was composed of around 20,000 protein coding genes.
This is an accepted version of this page This is the latest accepted revision, reviewed on 28 January 2025. Science of genes, heredity, and variation in living organisms This article is about the general scientific term. For the scientific journal, see Genetics (journal). For a more accessible and less technical introduction to this topic, see Introduction to genetics. For the Meghan Trainor ...