Genetic variability

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Genetic variability is either the presence of, or the generation of, genetic differences. It is defined as "the formation of individuals differing in genotype, or the presence of genotypically different individuals, in contrast to environmentally induced differences which, as a rule, cause only temporary, nonheritable changes of the phenotype." [1] Genetic variability in a population promotes biodiversity, as it ensures that no two living things are exactly alike. [2] While many factors can cause genetic variability, some factors can also decrease genetic variability.

Contents

Species variability refers to the observable differences within a species, often encompassing morphological, physiological, behavioral, or phenotypic traits. While genetic variability contributes to species variability, external factors like the environment or developmental conditions can also influence the traits expressed.

Causes

There are many sources of genetic variability in a population:

DNA damages are very frequent, occurring more than 60,000 times a day per cell on average in humans. This is due to metabolic or hydrolytic processes as summarized in DNA damage (naturally occurring). Most DNA damages are accurately repaired by various natural DNA repair mechanisms. However, some DNA damages remain and give rise to mutations.
Additionally, not all types of mutations occur as much as others do. Some mutations might have a huge impact on the human body, and some might not. It depends on what combination of base pairs is changed. [8]
Most spontaneously arising mutations result from error prone replication (translesion synthesis) past a DNA damage in the template strand. For example, in yeast more than 60% of spontaneous single-base pair substitutions and deletions are likely caused by translesion synthesis. [9] Another significant source of mutation is an inaccurate DNA repair process, non-homologous end joining, that is often employed in repair of DNA double-strand breaks. [10] (Also see Mutation.) Thus, it seems that DNA damages are the underlying cause of most spontaneous mutations, either because of error-prone replication past damages or error-prone repair of damages.

Factors that decrease genetic variability

There are many sources that decrease genetic variability in a population:

See also

References

  1. Rieger, R., Michaelis, A., Green, M.M. (1968), A glossary of genetics and cytogenetics: Classical and molecular, New York: Springer-Verlag, ISBN   978-0-387-07668-3
  2. Sousa, P., Froufe, E., Harris, D.J., Alves, P.C. & Meijden, A., van der. 2011. Genetic diversity of Maghrebian Hottentotta (Scorpiones: Buthidae) scorpions based on CO1: new insights on the genus phylogeny and distribution. African Invertebrates 52 (1). "Archived copy". Archived from the original on 2011-10-04. Retrieved 2011-05-03.{{cite web}}: CS1 maint: archived copy as title (link)
  3. 1 2 Stapley J, Feulner PG, Johnston SE, Santure AW, Smadja CM (2017-12-19). "Recombination: the good, the bad and the variable". Philosophical Transactions of the Royal Society B: Biological Sciences. 372 (1736) 20170279. doi:10.1098/rstb.2017.0279. ISSN   0962-8436. PMC   5698631 . PMID   29109232.
  4. Ehrich, Dorothy, Per Erik Jorde (2005). "High Genetic Variability Despite High-Amplitude Population Cycles in Lemmings". Journal of Mammalogy. 86 (2): 380–385. doi: 10.1644/BER-126.1 .
  5. Zhang S, Lin YH, Tarlow B, Zhu H (2019-06-18). "The origins and functions of hepatic polyploidy". Cell Cycle. 18 (12): 1302–1315. doi:10.1080/15384101.2019.1618123. ISSN   1538-4101. PMC   6592246 . PMID   31096847.
  6. Linhart, Yan, Janet Gehring (2003). "Genetic Variability and its Ecological Implications in the Clonal Plant Carex scopulurum Holm. In Colorado Tundra". Arctic, Antarctic, and Alpine Research. 35 (4): 429–433. doi:10.1657/1523-0430(2003)035[0429:GVAIEI]2.0.CO;2. ISSN   1523-0430. S2CID   86464133.
  7. 1 2 Wills, Christopher (1980). Genetic Variability . New York: Oxford University Press. ISBN   978-0-19-857570-2.{{cite book}}: CS1 maint: publisher location (link)
  8. Eichler EE (2019-07-04). "Genetic Variation, Comparative Genomics, and the Diagnosis of Disease". New England Journal of Medicine. 381 (1): 64–74. doi:10.1056/NEJMra1809315. ISSN   0028-4793. PMC   6681822 . PMID   31269367.
  9. Kunz BA, Ramachandran K, Vonarx EJ (April 1998). "DNA sequence analysis of spontaneous mutagenesis in Saccharomyces cerevisiae". Genetics. 148 (4): 1491–505. doi:10.1093/genetics/148.4.1491. PMC   1460101 . PMID   9560369.
  10. Huertas P (January 2010). "DNA resection in eukaryotes: deciding how to fix the break". Nat. Struct. Mol. Biol. 17 (1): 11–6. doi:10.1038/nsmb.1710. PMC   2850169 . PMID   20051983.