Differentially expressed genes match bill morphology and plumage despite largely undifferentiated genomes in a Holarctic songbird. Issue 12 (30th March 2015)

• Record Type: Journal Article
• Authors: Mason, Nicholas A.; Taylor, Scott A.
• Is Part Of: Molecular ecology. Volume 24:Issue 12(2015)
• Page Start: 3009
• Page End: 3025
• Publication Date: 2015-03-30
• Subjects: Molecular ecology -- Periodicals; Molecular population biology -- Periodicals; 576
• DOI: 10.1111/mec.13140
• Languages: English
• ISSNs: 0962-1083

Abstract

<abstract abstract-type="main" id="mec13140-abs-0001"> <title>Abstract</title> <p>Understanding the patterns and processes that contribute to phenotypic diversity and speciation is a central goal of evolutionary biology. Recently, high‐throughput sequencing has provided unprecedented phylogenetic resolution in many lineages that have experienced rapid diversification. The Holarctic redpoll finches (Genus: <italic>Acanthis</italic>) provide an intriguing example of a recent, phenotypically diverse lineage; traditional sequencing and genotyping methods have failed to detect any genetic differences between currently recognized species, despite marked variation in plumage and morphology within the genus. We examined variation among 20 712 anonymous single nucleotide polymorphisms (SNPs) distributed throughout the redpoll genome in combination with 215 825 SNPs within the redpoll transcriptome, gene expression data and ecological niche modelling to evaluate genetic and ecological differentiation among currently recognized species. Expanding upon previous findings, we present evidence of (i) largely undifferentiated genomes among currently recognized species; (ii) substantial niche overlap across the North American <italic>Acanthis</italic> range; and (iii) a strong relationship between polygenic patterns of gene expression and continuous phenotypic variation within a sample of redpolls from North America. The patterns we report may be caused by high levels of ongoing gene flow between polymorphic populations, incomplete lineage sorting accompanying very recent or ongoing divergence, variation in <italic>cis‐</italic>regulatory elements, or phenotypic plasticity, but do not support a scenario of prolonged isolation and subsequent secondary contact. Together, these findings highlight ongoing theoretical and computational challenges presented by recent, rapid bouts of phenotypic diversification and provide new insight into the evolutionary dynamics of an intriguing, understudied non‐model system.</p> </abstract>