Patterns and Processes of Genetic Diversification in Solitary and Social Subterranean Rodents

Lacey0128857 PI将研究来自阿根廷西南部的两种Tuco-tucos(啮齿目：线虫科)的社会行为、人口统计学和遗传变异之间的关系。阿根廷利马河谷群居的群居物种Tuco-tuco和孤独的巴塔哥尼亚Tuco-tuco(C.haigi)的存在为探索社会性对相似栖息地密切相关物种遗传变异的影响提供了一个不同寻常的机会。使用从每个物种10个种群收集的组织样本中提取的DNA，将量化微卫星和主要组织相容性复合体(MHC)基因座的变异。这些数据将被用来确定如何在每个物种的种群内和种群之间分配遗传变异。具体地说，PI将检验这样一个假设，即群体生活与MHC基因多样性的加强选择有关，MHC基因是与脊椎动物免疫反应相关的基因。为了确定在MHC基因上的选择是否受到群体生活物种成员中可能更大的病原体暴露的影响，将评估由PI抽样的所有群体的跳蚤和跳蚤传播的巴尔通体细菌的流行率。这项研究很重要，因为它是第一批对非人类脊椎动物自然种群的研究之一，目的是(1)将行为和人口统计学变量与MHC变异模式联系起来，(2)探索病原体暴露的行为中介差异在MHC基因选择中的作用。该项目的这两个方面都将显著提高我们对脊椎动物所观察到的遗传变异模式背后的过程的理解。该项目还将大大有助于我们了解濒危殖民地Tuco-Tuco的生物学，这种Tuco-Tuco是利马山谷西部和周围丘陵的特有物种。具体地说，通过邀请阿根廷大学生协助该项目，国际和平研究所将促进当地生物学家参与对这种鲜为人知的物种的研究和管理。

Lacey0128857The PI will examine relationships among social behavior, demography, and genetic variation in two species of tuco-tucos (Rodentia: Ctenomyidae) from southwestern Argentina. The presence of both the group-living colonial tuco-tuco (Ctenomys sociabilis) and the solitary Patagonian tuco-tuco (C. haigi) in Argentina's Limay Valley provides an unusual opportunity to explore the effects of sociality on genetic variation in closely related species that occur in similar habitats. Using DNA extracted from tissue samples collected from 10 populations per species, variation at both microsatellite and Major Histocompatibility Complex (MHC) loci will be quantified. These data will be used to determine how genetic variation is apportioned within and among populations of each species. Specifically, the PI will test the hypothesis that group living is associated with enhanced selection for diversity at MHC genes, which are the genes associated with the vertebrate immune response. To determine if selection on MHC genes is influenced by presumably greater pathogen exposure among members of group-living species, the prevalence of fleas and flea-borne bacteria of the genus Bartonella will be assessed for all populations of C. sociabilis and C. haigi sampled by the PI. The proposed research is important in that it is one of the first studies of natural populations of non-human vertebrates to (1) link behavioral and demographic variables to patterns of MHC variation and (2) explore the role of behaviorally-mediated differences in pathogen exposure in generating selection on MHC genes. Both aspects of the project will significantly improve our understanding of the processes underlying observed patterns of genetic variation in vertebrates. The project will also contribute significantly to our understanding of the biology of the endangered colonial tuco-tuco, which is endemic to the western Limay Valley and surrounding hills. Specifically, by engaging Argentine university students to assist with the project, the PI will facilitate involvement of local biologists in the study and management of this little-known species.