A gene-based genetic linkage map of the collared flycatcher (Ficedula albicollis) reveals extensive synteny and gene order conservation during 100 million years of avian evolution

BBy taking advantage of a recently developed reference marker set for avian genome analysis we have constructed a gene-based genetic map of the collared flycatcher, an important "ecological model" for studies of life history evolution, sexual selection, speciation and quantitative genetics. A pedigree of 322 birds from a natural population was genotyped for 384 single nucleotide polymorphisms (SNPs) from 170 protein-coding genes and 71 microsatellites. Altogether, 147 gene markers and 64 microsatellites form 33 linkage groups with a total genetic distance of 1787 cM. Male recombination rates are on average 22% higher than female rates (total distance 1982 cM vs. 1627 cM). The ability to anchor the collared flycatcher map with the chicken genome via the gene-based SNPs revealed an extraordinary degree of both synteny and gene order conservation during avian evolution. The great majority of chicken chromosomes correspond to a single linkage group in collared flycatchers, with only a few cases of inter- and intra-chromosomal rearrangements. The rate of chromosomal diversification, fissions/fusions and inversions combined, is thus considerably lower in birds (0.05/Myr) than in mammals (0.6-2.0/Myr). A dearth of repeat elements, known to promote chromosomal breakage, in avian genomes may contribute to their stability. The degree of genome stability is likely to have important consequences for general evolutionary patterns and may for example explain the comparatively slow rate by which genetic incompatibility between lineages of birds evolves.

Key Words: birds, chromosomal rearrangement, comparative mapping, microsatellites, single nucleotide polymorphism (SNP)

Online ISS 1091-6490
Copyright 2008 by the Genetics Society of America
phone: 412-268-1812   fax: 412-268-1813   email: genetics-gsa{at}andrew.cmu.edu