Editing Conservation genetics (section)

==Contributors to extinction==
Species extinction can be attributed to a multitude of factors. [[Inbreeding]] of closely related individuals has been known to reduce the genetic fitness of a larger population. [[Inbreeding depression]] from reduced fitness has long been theorized to be a link towards extinction. Lethal or non-advantageous allelic combinations increase, with disease susceptibility and lower fertility rates rising in both plant and animal populations.<ref>{{Cite journal |last=Lynch |first=Michael |date=1991-05-01 |title=The Genetic Interpretation of Inbreeding Depression and Outbreeding Depression |url=https://onlinelibrary.wiley.com/action/showCitFormats?doi=10.1111/j.1558-5646.1991.tb04333.x |journal=Evolution |language=en |volume=45 |issue=3 |pages=622–629 |doi=10.1111/j.1558-5646.1991.tb04333.x |pmid=28568822 |issn=1558-5646}}</ref><ref>{{Cite journal |last1=Hedrick |first1=Philip W. |last2=Kalinowski |first2=Steven T. |date=2000-11-01 |title=Inbreeding Depression in Conservation Biology |url=https://www.annualreviews.org/content/journals/10.1146/annurev.ecolsys.31.1.139 |journal=Annual Review of Ecology, Evolution, and Systematics |language=en |volume=31 |issue=1 |pages=139–162 |doi=10.1146/annurev.ecolsys.31.1.139 |bibcode=2000AnRES..31..139H |issn=1543-592X|url-access=subscription }}</ref> In small, inbreeding populations, an increase in deleterious mutations may also arise, further reducing fitness and allowing for further genetic complications.

[[Population fragmentation]] may also contribute toward species extinction. Habitat loss or natural events may cut populations off from one another, resulting in two or more groups having little to no contact with each other.<ref>{{Cite journal |title=Effects of Habitat Loss and Fragmentation on Population Dynamics | date=2005 |url=https://conbio.onlinelibrary.wiley.com/doi/epdf/10.1111/j.1523-1739.2005.00208.x |language=en |doi=10.1111/j.1523-1739.2005.00208.x |issn=1523-1739 | last1=Wiegand | first1=Thorsten | last2=Revilla | first2=Eloy | last3=Moloney | first3=Kirk A. | journal=Conservation Biology | volume=19 | pages=108–121 | url-access=subscription }}</ref> Fragmentation may induce inbreeding in these smaller populations.

When two populations with distinct genetic makeups mate, [[outbreeding depression]] may occur and reduce the fitness of one or both populations. Outbreeding depression and its consequences can be just as detrimental as inbreeding depression.<ref>{{Cite journal |last=Edmands |first=Suzanne |date=2007 |title=Between a rock and a hard place: evaluating the relative risks of inbreeding and outbreeding for conservation and management |url=https://onlinelibrary.wiley.com/doi/full/10.1111/j.1365-294X.2006.03148.x |journal=Molecular Ecology |language=en |volume=16 |issue=3 |pages=463–475 |doi=10.1111/j.1365-294X.2006.03148.x |pmid=17257106 |bibcode=2007MolEc..16..463E |issn=1365-294X|url-access=subscription }}</ref> Some conservation efforts focus on the genetic distinctions between populations of the same species. Outbreeding depression could affect the success rate of these conservation efforts.