Endangered Species' Genetic Diversity Explains their Decline

Some species may face extinction when they are not able to adapt as easily to changing environments or defend against new diseases. To better identify or rank threatened and engendered species, researchers from Purdue University suggest using the animals' rate of genetic diversity loss.

"Genetic diversity is a key component to the long-term survival of a population," Janna Willoughby, a then-doctoral student in wildlife genetics, said in a statement. "The approach we developed identifies populations with limited genetic diversity that isn't going to be enough to allow the population to persist over time. We found that this method performs significantly better than current methods for identifying species in need of conservation efforts."

Willoughby, along with Andrew DeWoody, a professor of genetics, studied positions of genes on chromosomes in order to estimate genetic diversity loss among wildlife populations. From this they were able to develop a statistical approach for estimating the number of generations remaining before a species' genetic variation reaches a low threshold.

According to their study, researchers found a reduced genetic variation in threatened species. They attributed this to circumstances such as inbreeding, which can result when population sizes are small.

The researchers also acknowledged the many methods for determining that a species is either threatened or endangered, including the International Union for Conservation of Nature (IUNC). They examined the IUNC's Red List to see how effective it was at identifying poor genetic diversity in species; however, the researchers discovered that the organization's criteria was not closely related to genetic diversity.

"The criteria of many conservation organizations were formulated before the availability of genetic data we have today," DeWoody said in the release. "But genetic methodology has advanced so rapidly that factoring in genetic diversity is now pretty straightforward."

Their study will be published in the November issue of Biological Conservation.

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