A consensus linkage map of the chicken genome

Abstract

A consensus linkage map has been developed in the chicken that combines all of the genotyping data from the three available chicken mapping populations. Genotyping data were contributed by the laboratories that have been using the East Lansing and Compton reference populations and from the Animal Breeding and Genetics Group of the Wageningen University using the Wageningen/Euribrid population. The resulting linkage map of the chicken genome contains 1889 loci. A framework map is presented that contains 480 loci ordered on 50 linkage groups. Framework loci are defined as loci whose order relative to one another is supported by odds greater then 3. The possible positions of the remaining 1409 loci are indicated relative to these framework loci. The total map spans 3800 cM, which is considerably larger than previous estimates for the chicken genome. Furthermore, although the physical size of the chicken genome is threefold smaller then that of mammals, its genetic map is comparable in size to that of most mammals. The map contains 350 markers within expressed sequences, 235 of which represent identified genes or sequences that have significant sequence identity to known genes. This improves the contribution of the chicken linkage map to comparative gene mapping considerably and clearly shows the conservation of large syntenic regions between the human and chicken genomes. The compact physical size of the chicken genome, combined with the large size of its genetic map and the observed degree of conserved synteny, makes the chicken a valuable model organism in the genomics as well as the postgenomics era. The linkage maps, the two-point lod scores, and additional information about the loci are available at web sites in Wageningen (http://www.zod.wau.nl/vf/ research/chicken/frame_chicken.html) and East Lansing (http://poultry.mph.msu.edu/).

Figure 1

Framework consensus linkage map of the chicken genome. The framework loci (loci whose order relative to one another is supported by odds >3, Keats et al. 1991) have been ordered and their position is indicated by the number at left. The possible location of the loci whose order is not supported by odds >3 is indicated by an error bar. Loci that have been mapped cytogenetically are underlined; those known to represent expressed sequences (identified genes and ESTs) are shown in boldface type.

Figure 1

Framework consensus linkage map of the chicken genome. The framework loci (loci whose order relative to one another is supported by odds >3, Keats et al. 1991) have been ordered and their position is indicated by the number at left. The possible location of the loci whose order is not supported by odds >3 is indicated by an error bar. Loci that have been mapped cytogenetically are underlined; those known to represent expressed sequences (identified genes and ESTs) are shown in boldface type.

Figure 1

Framework consensus linkage map of the chicken genome. The framework loci (loci whose order relative to one another is supported by odds >3, Keats et al. 1991) have been ordered and their position is indicated by the number at left. The possible location of the loci whose order is not supported by odds >3 is indicated by an error bar. Loci that have been mapped cytogenetically are underlined; those known to represent expressed sequences (identified genes and ESTs) are shown in boldface type.

Figure 1

Framework consensus linkage map of the chicken genome. The framework loci (loci whose order relative to one another is supported by odds >3, Keats et al. 1991) have been ordered and their position is indicated by the number at left. The possible location of the loci whose order is not supported by odds >3 is indicated by an error bar. Loci that have been mapped cytogenetically are underlined; those known to represent expressed sequences (identified genes and ESTs) are shown in boldface type.

Figure 2

Comparative mapping results among chicken, man, and mouse. The order of the loci is according to the linkage map shown in Fig. 1. The second column in each linkage group shows the location of the loci on the human cytogenetic map according to Genome Data Base (http://www.gdb.org/); the third column shows the map location in the mouse. Blocks of conserved synteny between chicken and man and between chicken and mouse are shaded.