AUGUST 21, 2019
by Michael Miller, University of Cincinnati
A study by the University of Cincinnati found that Charles Darwin's famous finches defy what has long been considered a key to evolutionary success: genetic diversity.
The research on finches of the Galapagos Islands could change the way conservation biologists think about a species' potential for extinction in naturally fragmented populations.
UC graduate Heather Farrington and UC biologists Kenneth Petren and Lucinda Lawson found that genetic diversity was not a good predictor of whether populations of finches would survive. The study was published in Conservation Genetics.
A UC lab analysis of century-old museum specimens found that six of eight extinct populations had more genetic diversity than similar museum specimens from which descendants survive today. In most other species, low genetic diversity is a signal of a population in decline.
Researchers examined 212 tissue samples from museum specimens and living birds. Some of the museum specimens in the study were collected by Darwin himself in 1835. Only one of the extinct populations, a species called the vegetarian finch, had lower genetic diversity compared to modern survivors.
Lawson said the findings are explained by the fact that these birds can migrate in between populations.