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Estimation of linkage disequilibrium and interspecific gene flow in F icedula flycatchers by a newly developed 50k single‐nucleotide polymorphism array
Author(s) -
Kawakami Takeshi,
Backström Niclas,
Burri Reto,
Husby Arild,
Olason Pall,
Rice Amber M.,
Ålund Murielle,
Qvarnström Anna,
Ellegren Hans
Publication year - 2014
Publication title -
molecular ecology resources
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.96
H-Index - 136
eISSN - 1755-0998
pISSN - 1755-098X
DOI - 10.1111/1755-0998.12270
Subject(s) - biology , linkage disequilibrium , genetics , population , genome , evolutionary biology , single nucleotide polymorphism , gene , genotype , demography , sociology
With the access to draft genome sequence assemblies and whole‐genome resequencing data from population samples, molecular ecology studies will be able to take truly genome‐wide approaches. This now applies to an avian model system in ecological and evolutionary research: Old World flycatchers of the genus F icedula , for which we recently obtained a 1.1 Gb collared flycatcher genome assembly and identified 13 million single‐nucleotide polymorphism ( SNP )s in population resequencing of this species and its sister species, pied flycatcher. Here, we developed a custom 50K I llumina i S elect flycatcher SNP array with markers covering 30 autosomes and the Z chromosome. Using a number of selection criteria for inclusion in the array, both genotyping success rate and polymorphism information content (mean marker heterozygosity = 0.41) were high. We used the array to assess linkage disequilibrium ( LD ) and hybridization in flycatchers. Linkage disequilibrium declined quickly to the background level at an average distance of 17 kb, but the extent of LD varied markedly within the genome and was more than 10‐fold higher in ‘genomic islands’ of differentiation than in the rest of the genome. Genetic ancestry analysis identified 33 F 1 hybrids but no later‐generation hybrids from sympatric populations of collared flycatchers and pied flycatchers, contradicting earlier reports of backcrosses identified from much fewer number of markers. With an estimated divergence time as recently as <1 Ma, this suggests strong selection against F 1 hybrids and unusually rapid evolution of reproductive incompatibility in an avian system.