Submitted to: Cytogenetics and Cell Genetics
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: February 5, 1999
Publication Date: N/A
Interpretive Summary: Current data suggest that the genomes of cattle, sheep, and goats are highly similar, due to their close evolutionary relationship. As far as we know, all three species have the same genes and relatively minor differences in the gene sequences are the basis for the appearance of these three species. However, at this point this is only a working hypothesis. In order to further define the similarities between species, and to reveal possible differences that might contribute to the obvious physical differences in the animals, we have been characterizing the genomes of all three species. PAX8 is a gene that plays important roles during development of animal embryos, and we had previously shown the surprising result that PAX8 gene lies on cattle chromosome 11, instead of chromosome 2 which would have been predicted from studies of chromosomes of other mammals, including mice and humans. We tested whether this difference is also seen in sheep and goat by making a PAX8 gene probe that is capable of directly binding to the chromosomes and telling us where the genes are in the genome. The results showed that the PAX8 gene does not lie on chromosome 2 in any of these species. In concert with our other studies, this provides further evidence that the genomes of these three species are highly similar at a very fine level.
Technical Abstract: The PAX8 gene, a member of the human paired box gene family, was mapped by FISH to chromosome 11 in cattle and goat and to the short arm of chromosome 3 in sheep. The cytogenetic position of PAX8 on BTA 11 and on its homologue OAR 3p lies in the region where the interleukin beta (IL1B) gene has been previously located, (BTA 11q22.3 and OAR 3p25 >q26 respectively, Lopez- Corrales et al., 1998). The results indicated that PAX8 as well as interleukin beta and interleukin alpha (IL1B and IL1A) genes detected on the human chromosome segment HSA2q13 >q21 maintain a similar order and location between these three related species. In addition, the breakpoint in conserved synteny between bovids and humans can now be narrowed to a position between the protein C and PAX8 genes, which lie in close proximity on HSA2.