Microdissected bovine X chromosome segment delineates homoeologous chromosomal regions in sheep, goat and buffalo.

The terminal part of the long arm of the bovine X chromosome (bands Xq41-q43) was microdissected. The DNA thus obtained was PCR amplified, labelled and used as painting probe on cattle, sheep, goat and buffalo chromosomes. In cattle, as expected, distinct hybridization signals were observed on bands Xq41-q43. In sheep and goat, the painting signals were observed on the proximal part of the long arm of the X chromosome, adjacent to the centromere (Xp12-q12). In buffalo, however, the terminal part of the X chromosome involving bands q44-q47 was painted. The findings contribute towards developing a better understanding of the comparative organization of the X chromosome in the four bovidae species. Proposed models of evolutionary rearrangements within the X chromosome of the four species are examined in light of the results obtained.