title: A genomic investigation of the putative contact zone between divergent Brown Creeper (Certhia americana) lineages: chromosomal patterns of genetic differentiation.
abstract: Sky islands, or montane forest separated by different lowland habitats, are highly fragmented regions that potentially limit gene flow between isolated populations. In the sky islands of the Madrean Archipelago (Arizona, USA), various taxa display different phylogeographic patterns, from unrestricted gene flow among sky islands to complex patterns with multiple distinct lineages. Using genomic-level approaches allows the investigation of differential patterns of gene flow, selection, and genetic differentiation among chromosomes and specific genomic regions between sky island populations. Here, we used thousands of SNPs to investigate the putative contact zone of divergent Brown Creeper (Certhia americana) lineages in the Madrean Archipelago sky islands. We found the two lineages to be completely allopatric (during the breeding season) with a lack of hybridization and gene flow between lineages and no genetic structure among sky islands within lineages. Additionally, the two lineages inhabit different climatic and ecosystem conditions and have many local primary song dialects in the southern Arizona mountain ranges. We identified a positive relationship between genetic differentiation and chromosome size, but the sex chromosome (Z) was not found to be an outlier. Differential patterns of genetic differentiation per chromosome may be explained by genetic drift--possibly in conjunction with non-random mating and non-random gene flow--due to variance in recombination rates among chromosomes.
authors.affiliation: a Biodiversity Institute, University of Kansas, Lawrence, KS 66045, USA.|b Department of Ecology and Evolutionary Biology, University of Kansas, Lawrence, KS 66045, USA.
authors.forename: Joseph D
authors.initials: JD
authors.lastname: Manthey
authors.affiliation: a Biodiversity Institute, University of Kansas, Lawrence, KS 66045, USA.
authors.forename: Mark B
authors.initials: MB
authors.lastname: Robbins
authors.affiliation: a Biodiversity Institute, University of Kansas, Lawrence, KS 66045, USA.|b Department of Ecology and Evolutionary Biology, University of Kansas, Lawrence, KS 66045, USA.
authors.forename: Robert G
authors.initials: RG
authors.lastname: Moyle
mesh_terms: D000818:Animals; D001130:Arizona; D019143:Evolution, Molecular; D051456:Gene Flow; D049810:Genetic Speciation; D023281:Genomics; D059014:High-Throughput Nucleotide Sequencing; D058974:Phylogeography; D020641:Polymorphism, Single Nucleotide; D017422:Sequence Analysis, DNA; D020308:Songbirds / Q000235:genetics*; D014828:Vocalization, Animal
keywords: chromosomal patterns; contact zone; distributions chromosomiques; next-generation sequencing; sky islands; séquençage de nouvelle génération; zone de contact; îlots forestiers en altitude