A comparative genetic map of the turkey genome

Abstract

Genetic markers (microsatellites and SNPs) were used to create and compare maps of the turkey and chicken genomes. A physical map of the chicken genome was built by comparing sequences of turkey markers with the chicken whole-genome sequence by BLAST analysis. A genetic linkage map of the turkey genome (Meleagris gallopavo) was developed by segregation analysis of genetic markers within the University of Minnesota/Nicholas Turkey Breeding Farms (UMN/NTBF) resource population. This linkage map of the turkey genome includes 314 loci arranged into 29 linkage groups. An additional 40 markers are tentatively placed within linkage groups based on two-point LOD scores and 16 markers remain unlinked. Total map distance contained within linkage groups is 2,011 cM with the longest linkage group (47 loci) measuring 413.3 cM. Average marker interval over the 29 linkage groups was 6.4 cM. All but one turkey linkage group could be aligned with the physical map of the chicken genome. The present genetic map of the turkey provides a comparative framework for future genomic studies.

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

“…In the end, only two rearrangements that distinguish the karyotypes of the chicken and the collared flycatcher are strongly supported by our data (supplemental data) and are also independently confirmed in other species. These include a fission of the ancestral chromosome 1 in Passeriformes to yield the collared flycatcher linkage groups Fal3 and Fal8 (supported by data in Guttenbach et al 2003;Derjusheva et al 2004;Itoh and Arnold 2005) and the fusion of ancestral chromosomes 4 (corresponding to Fal5) and 10 (Fal18) in the chicken lineage to yield Gga4 (supported by Reed et al 2005). One or a few more rearrangements could be indicated by our data but would need a denser map for confirmation.…”

“…However, as in several galliform birds (Groenen et al 2000;Kayang et al 2004;Reed et al 2005), the difference is not as pronounced as that seen in most mammals [in humans, for example, the female rate is $1.6 times higher than the male rate (Broman et al 1998)]. The great reed warbler shows a quite contrasting pattern, with a more than twofold excess of recombination in females (Hansson et al 2005;Dawson et al 2007), i.e., against the expectations of the HaldaneHuxley rule.…”

“…However, the physical marker density and chromosomal coverage in the great reed warbler map is relatively low, especially for markers informative in comparative mapping, so it may be that the resolution is not sufficient for detection of some intrachromosomal rearrangements. Neither of these inversions is seen in the fairly dense map of the turkey genome (Reed et al 2005) so they may have arisen either early in the evolution of Galliformes or somewhere along the passerine lineage leading to the collared flycatcher. The great reed warbler map revealed two clear cases of inversions when compared to chicken chromosomes 1 and 2, respectively (Dawson et al 2007).…”

“…Genetic maps are available for turkey (Reed et al 2005) and quail (Kayang et al 2006), two agricultural species that are closely related to chicken as members of the order Galliformes. However, a lack of genetic markers, in particular those informative for comparative mapping, has been a major obstacle to linkage analyses of bird species belonging to other orders.…”

Genetic Mapping in a Natural Population of Collared Flycatchers (Ficedula albicollis): Conserved Synteny but Gene Order Rearrangements on the Avian Z Chromosome

“…Unfortunately, this is not the case for most species of birds. In addition to the well-established linkage map of the chicken (Groenen et al 2001), mapping is underway in some domestic galliforms of agricultural interest, including quail (Kikuchi et al 2005) and turkey (Reed et al 2005), but there are only preliminary attempts at linkage mapping in wild species, notably by the work of Hansson et al (2005). Given the role birds play in evolutionary research, improved genetic resources, such as the development of detailed linkage maps, are likely to open the way for advancing our understanding of the role of natural selection in wild bird populations (Edwards et al 2005).…”