High resolution RBA-banding comparison between early prometaphase chromosomes of cattle (Bos taurus L.) and goat (Capra hircus L.) at 700 band level.

High resolution RBA-banded early prometaphase chromosomes of cattle (Bos taurus L.) and goat (Capra hircus L.), from thymidine synchronized lymphocyte cultures, are compared at a level of 700 bands per haploid genome, with the purpose of detecting the extent of banding homologies between the two species and improving the resolution level of the ISCNDA (1989) standardized RBA-banded karyotypes. The results demonstrate that, at this level of resolution, at least 10 autosomes can be fully homologized between the two species, namely chromosomes 11, 16, 17, 18, 20, 21, 22, 23, 24 and 26, whereas the remaining autosomes show variations in some regions which require further investigations on more elongated chromosomes. Such investigations should also involve the use of GTG, GBG and RBG-banding techniques. These variations concern basically the relative distance of the bands from the centromeres or telomeres, appearance of subbands, and clustering of some positive bands.