Phylogeographic inference using Bayesian model comparison across a fragmented chorus frog species complex.

Area of Science:

• Evolutionary Biology
• Conservation Genetics
• Phylogeography

Background:

• Fragmented species complexes offer insights into biogeographic history and genetic variation.
• Advances in sequencing and phylogeography allow for large, complex data analysis.
• Designing effective phylogeographic studies remains a challenge.

Purpose of the Study:

• To investigate biogeographic hypotheses and infer genetic structure in a chorus frog species complex.
• To analyze the phylogeography of the Illinois chorus frog (Pseudacris illinoensis) and its relationship to Pseudacris streckeri.
• To utilize a Bayesian model comparison approach for robust phylogeographic inference.

Main Methods:

• Implemented a Bayesian model comparison approach.
• Collected a multitiered genetic data set using high-throughput sequencing (nuclear loci, mitochondrial genes, microsatellites).
• Performed phylogenetic analyses and migration modeling.

Main Results:

• Uncovered a deep evolutionary divergence between central Texas populations and other P. streckeri/P. illinoensis populations.
• Indicated that the disjunct distribution of P. illinoensis is a more recent event.
• Identified central Texas as a potential refugium with subsequent population expansions.

Conclusions:

• The study supports distinct genetic management units for disjunct northern and southern P. illinoensis populations.
• Provides an evolutionary context for conservation of P. illinoensis.
• Demonstrates the effectiveness of model-based approaches in phylogeographic studies.