Fluorescent in situ hybridization mapping of three fecundity genes on cattle, river buffalo, sheep and goat

One of the goals of molecular cytogenetics applied to livestock is the extension of their genetic physical maps, especially of loci containing genes related to productions. In this study, a comparative fluorescence in situ (FISH) mapping of three genes related to fecundity of cattle, river buffalo, sheep and goat is reported using bovine BAC-clones taking in account the data available on the BovMap database and considering their physical position and the data obtained from banding experiments. The following three gene sequences were mapped: tumor necrosis factor-? (TNF), correlated to male fertility; signal transducer and activator of transcription 5A (STAT5A), important for its influence on milk production and reproduction activity; melatonin receptor 1A (MTNR1A) important for reproductive seasonality. BAC probes containing these gene sequences were assigned by FISH, for the first time, on RB-banded chromosomes of these four important bovids. TNF was assigned to BTA/CHI23q21-22, OAR20q21-22 and BBU 2p21-22; STAT5A was assigned to BTA/CHI19q17-21, OAR11q17-21 and BBU3p15-21; MTNR1A was assigned to BTA/CHI27q14-15, OAR26q14-15 and BBU1p21-22. The three loci were located in homoeologous chromosomes and chromosome bands, underling the high degree of chromosome homologies among Bovids and extending the cytogenetic maps of this economically important species.