Identifying drivers of historical genetic decline in an endemic Patagonian rodent, the Colonial Tuco-tuco, Ctenomys sociabilis (Rodentia: Ctenomyidae)

TAMMONE, MAURO N.; PARDIÑAS, ULYSES F. J.; LACEY, EILEEN A.

BIOLOGICAL JOURNAL OF THE LINNEAN SOCIETY

WILEY-BLACKWELL PUBLISHING, INC

Año: 2018

0024-4066

Understanding the causes of pronounced loss of genetic diversity in natural populationsmay generate important insights into the evolutionary significance of these events.However, these analyses are typically based on post-reduction levels and patterns ofvariability in modern populations, which often leads to results that are biased towardmore recent demographic events. In this context, population data recovered from thefossil record provide a powerful resource for studying historic processes of decline. Usingradiocarbon dating, stratigraphic analyses and DNA sequencing, we compared geneticvariation and relative abundances of fossil specimens from the mid-Holocene to today toevaluate potential explanations for the marked historic loss of genetic diversity in thecolonial tuco-tuco (Ctenomys sociabilis), a subterranean rodent that is endemic toPatagonia. We conclude that a general pattern of climatic change during the mid-Holocene, particularly changes in precipitation, led to changes in abundance of suitablehabitats for this species. Loss of suitable habitat combined with the unusual demographicstructure of this species may have facilitated the decline of populations of C. sociabilis bydecreasing gene flow and increasing the potential for fixation of haplotypes due to geneticdrift. Our analyses of temporal changes in abundance and genetic diversity in ctenomyidshave implications for understanding more widespread patterns of Holocene change in themammalian fauna of Patagonia.