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United States Department of Agriculture

Agricultural Research Service

Title: The Chromosome 7 Linkage Group Developed at the U.S. Meat Animal Research Center

item Rohrer, Gary

Submitted to: Swine Chromosome 7 Workshop
Publication Type: Proceedings
Publication Acceptance Date: September 15, 1995
Publication Date: N/A

Technical Abstract: From our analyses using genotypic data of 1,034 loci, we have mapped 72 loci to porcine chromosome 7; 65 markers were microsatellites and seven were RFLP. This linkage group spans 156.6 cM with an average marker interval of 2.2 cM. There were four unlikely double recombination events detected with CHROMPIC from our data consisting of ~7,000 genotypes. When we merged the cytogenetic map with our linkage map we were able to conclude that the linkage map spans the entire chromosome. We observed only one recombination event out of 188 meioses within the region encompassing SLA loci. This recombination occurred within the Class III region and allowed us to order the Classes I-III-II along the chromosome. Physical assignments have determined that the MHC spans the centromere with Class I and III genes located on 7p and Class II genes located on 7q. Despite the large number of markers in this linkage group, three intervals >10 cM still exist. Additional highly polymorphic loci on chromosome 7 will be needed to identify and clone QTLs present in most economically relevant resource populations since marker heterozygosities will be lower in these populations.

Last Modified: 4/19/2015