Comparative mapping and positional candidate cloning of economic trait loci on bovine chromosomes 2 and 4

One of the major goals of genomic research for the livestock industries is to identify economic trait loci and directly select elite animals based on their genetic components. A resource herd comprising 701 animals from Angus x Brahman F;Radiation hybrid (RH) mapping is an efficient approach for physical mapping. Twenty-six loci, including eight selected genes and eighteen microsatellites, were used to construct a comprehensive RH map of BTA2. The orders obtained by the three mapping methods were in agreement.;Interval analyses were performed by integrating all the candidate genes into the genetic maps for BTA2 and BTA4. ETL peaks with LOD scores greater than 2 were detected for seven traits on BTA2, including WWT, OAWT, OMWT, ADGOF, SWT, HCW and KPH, and for two traits on BTA4, including C18:0 and R1. A candidate gene would be tentatively identified as the ETL if it was located in the 1-LOD interval containing an ETL. None of the candidate genes in these 1-LOD intervals based on the results of this study. Thus, further work will be needed in the future to identify additional candidate genes.