GENOMIC AND MORPHOLOGICAL ANALYSIS OF A SEMIPERMEABLE AVIAN HYBRID ZONE SUGGESTS ASYMMETRICAL INTROGRESSION OF A SEXUAL SIGNAL. (1st September 2014)

• Record Type: Journal Article
• Authors: Baldassarre, Daniel T.; White, Thomas A.; Karubian, Jordan; Webster, Michael S.
• Is Part Of: Evolution. Volume 68:Number 9(2014:Sep.)
• Page Start: 2644
• Page End: 2657
• Publication Date: 2014-09-01
• Subjects: Genotyping‐by‐sequencing -- geographic clines -- neutral diffusion -- red‐backed fairy‐wren -- reflectance spectrophotometry -- tension zone; Evolution -- Periodicals; Heredity -- Periodicals; Évolution (Biologie) -- Périodiques; Hérédité -- Périodiques; 338.47004094
• DOI: 10.1111/evo.12457
• Languages: English
• ISSNs: 0014-3820

Abstract

Abstract: Hybrid zones are geographic regions where differentiated taxa meet and potentially exchange genes. Increasingly, genomic analyses have demonstrated that many hybrid zones are semipermeable boundaries across which introgression is highly variable. In some cases, certain alleles penetrate across the hybrid zone in only one direction, recombining into the alternate genome. We investigated this phenomenon using genomic (genotyping‐by‐sequencing) and morphological (plumage reflectance spectrophotometry) analyses of the hybrid zone between two subspecies of the red‐backed fairy‐wren ( Malurus melanocephalus ) that differ conspicuously in a sexual signal, male back plumage color. Geographic cline analyses revealed a highly variable pattern of differential introgression, with many narrow coincident clines combined with several significantly wider clines, suggesting that the hybrid zone is a semipermeable tension zone. The plumage cline was shifted significantly into the genomic background of the orange subspecies, consistent with sexual selection driving asymmetrical introgression of red plumage alleles across the hybrid zone. This interpretation is supported by previous experimental work demonstrating an extra‐pair mating advantage for red males, but the role of genetic dominance in driving this pattern remains unclear. This study highlights the potential for sexual selection to erode taxonomic boundaries and promote gene flow, particularly at an intermediate stage of divergence.