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17 April 2014 12:48 pm ,
Vol. 344 ,
Officials last week revealed that the U.S. contribution to ITER could cost $3.9 billion by 2034—roughly four times the...
An experimental hepatitis B drug that looked safe in animal trials tragically killed five of 15 patients in 1993. Now,...
Using the two high-quality genomes that exist for Neandertals and Denisovans, researchers find clues to gene activity...
A new report from the Intergovernmental Panel on Climate Change (IPCC) concludes that humanity has done little to slow...
Astronomers have discovered an Earth-sized planet in the habitable zone of a red dwarf—a star cooler than the sun—500...
Three years ago, Jennifer Francis of Rutgers University proposed that a warming Arctic was altering the behavior of the...
- 17 April 2014 12:48 pm , Vol. 344 , #6181
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Inbreeding's Kiss of Death
1 April 1998 7:30 pm
Scientists have found a strong link between inbreeding--mating with first cousins and other close kin--and whether a small, isolated butterfly population went extinct. The finding, reported in tomorrow's Nature, bolsters the idea that genetic diversity must be considered when drawing up plans to protect endangered species.
The issue of whether a meager gene pool can lead to extinction in already fragmented populations has provoked "a hell of a lot of controversy," says Richard Frankham of Macquarie University in Australia. Although some biologists have argued for the power of inbreeding, a persuasive argument of late, he says, has been that climatic events and random fluctuations in population size are far more important in the wild.
But that's not the conclusion suggested by new data from Finland's Aland Islands, home to a Glanville fritillary butterfly "metapopulation"--many small, fragmented populations transiently connected when individuals fly between them. To see whether genetic diversity plays a role in extinction, a team led by population biologists Ilik Saccheri and Ilkka Hanski of the University of Helsinki in 1996 collected adult females from 42 populations and analyzed seven of their enzymes and one genomic DNA section for variants. After watching seven populations wink out in the last year, the team found that inbreeding accounted for as much as 26% of the differences from population to population in extinction rates. This link held up after ecological factors that also influence extinction, such as weather and habitat size, were taken into account.
The study is "as close as you'll get to direct evidence" that inbreeding figures in extinction, Frankham says. The findings, he and others say, suggest that wildlife managers should focus scarce resources on those threatened populations with larger gene pools within a species. Says Frankham, "This is going to be absolutely critical as we deal with fragmented populations."