Abstract
Recent data indicates that blotched tiger salamanders (Ambystoma tigrinum melanostictum) in northern regions of Yellowstone National Park are declining due to climate-related habitat changes. In this study, we used ancient and modern mitochondrial haplotype diversity to model the effective size of this amphibian population through recent geological time and to assess past responses to climatic changes in the region. Using subfossils collected from a cave in northern Yellowstone, we analyzed >700 base pairs of mitochondrial sequence from 16 samples ranging in age from 100 to 3300 years old and found that all shared an identical haplotype. Although mitochondrial diversity was extremely low within the living population, we still were able to detect geographic subdivision within the local area. Using serial coalescent modelling with Bayesian priors from both modern and ancient genetic data we simulated a range of probable population sizes and mutation rates through time. Our simulations suggest that regional mitochondrial diversity has remained relatively constant even through climatic fluctuations of recent millennia.
Highlights
Detailed contemporary genetic characteristics of a population can be analyzed to reveal aspects of its history
Genetic variation in modern populations of tiger salamanders (Ambystoma spp.) suggest complex colonization, migration and bottleneck patterns through their histories that could be explored in greater detail by anchoring modern genetic variation in ancient variation
The low mitochondrial diversity that we observed in modern A. t. melanostictum is comparable to the low mtDNA diversity described in other Ambystoma populations [26,27], and consistent with the low nuclear microsatellite diversity described for this population [28]
Summary
Detailed contemporary genetic characteristics of a population can be analyzed to reveal aspects of its history. The modern genetics of a population serve only as a snapshot of complex and dynamic processes averaged over time and biased by recent events. Incorporating ancient information into genetic studies can place a population into its historical context, and can reveal details of a population’s history that might otherwise be lost with time [1,2]. Amphibian populations are sensitive environmental indicators, tracking both aquatic and terrestrial environments, and their responses to historical environmental changes may lend insight into their prospects in rapidly changing modern ecosystems. No previous study has included assessments of ancient amphibian DNA, either in a phylogeographic or a population genetic context. We used amphibian samples from the last 3000 years to study the history of an amphibian population that has likely experienced declines and bottlenecks in past millennia and centuries [5], as well as in recent decades [6]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
