Stanford University biologist Elizabeth Hadly and her colleagues are using DNA extracted from ancient teeth-some more than 10,000 years old-to unravel the colonial tuco-tuco's mysterious past and pinpoint the cause of its low genetic diversity. The results are published in the April 20 edition of the journal PLoS Genetics.
''This advance in the analysis is fundamentally different from anything anyone has done with ancient DNA,'' says Hadly, an associate professor of biological sciences and co-author of the study. ''What we're trying to do is basically make a moving picture of their history instead of just a snapshot.''
Adopting a colonial lifestyle may have been the key to the rodent's survival, Hadly asserts, and could provide insight into the evolution of social behavior in other animals, including ants and humans.
Named for the ''tuc-tuc-tuc'' sound of its call, the colonial tuco-tuco (Ctenomys sociabilis) lives in remote highland savannah areas of southern Argentina. Unlike the more than 50 other tuco-tuco species that live mostly solitary lives, C. sociabilis lives in colonies. Several females frequently share one burrow and in captivity are known to nurse one another's young.
Almost entirely subterranean, colonial tuco-tucos rarely leave their burrows except for brief forays to collect the grassy vegetation on which they feed. When they do leave their colonies, the