Submitted to: Mammalian Genome
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: December 28, 1996
Publication Date: N/A
Interpretive Summary: A genetic linkage map of cattle is used to identifying genes that influence important traits. A total of 34 genetic markers were discovered and put into the linkage map. Of these 34, 5 were found to be at or near the end of their respective linkage groups. These 5 were then subjected to physical mapping by a process called fluorescence in situ hybridization (FISH). The results show only 2 of the 5 linkage groups actually cover the chromosomes down to the telomeric end, and identify areas where continued map development should be directed in the future. The map is comprised of a series of markers whose relative positions are known, similar to the mile markers on a highway map. Like the mile marker signs, genetic markers provide only distance information, i.e., how far it is to the next marker. Sometimes they may tell us how far away a gene of interest lies, similar to an "upcoming exit" sign on the freeway, but again this is only distance information. In order to maximize the utility of the genetic linkage map, we need to align it to the physical map of the bovine chromosomes. This is accomplished by providing "anchor" markers that give us both position along the linkage map highway, as well as position on the chromosome. These anchor loci act like towns on the highway map, so that we not only know where we are in terms of miles along the highway, but also where in relation to geographical landmarks.
Technical Abstract: We report the placement of 34 new microsatellite (ms) markers, isolated from a lambda phage genomic clone library, on the bovine genetic map by linkage to published markers. Five of these markers lie at or near the ends of linkage groups, and are used to establish chromosomal coverage and orientation. Fluorescence in situ hybridization (FISH) analysis demonstrates that the linkage groups on the U.S. Meat Animal Research Center (MARC) map extend to the telomeric region of chromosomes 7 and 10. Linkage groups on chromosomes 4, 6, and 14 appear to be less inclusive.