Development of a bovine X chromosome linkage group and painting probes to assess cattle, sheep, and goat X chromosome segment homologies.

Abstract

The X chromosome linkage group is conserved in placental mammals. However, X chromosome morphological differences, due to internal chromosome rearrangements, exist among mammalian species. We

An integrated genetic and physical map of the bovine X Chromosome

“…Loci which appeared to be linked near the telomeres and centromere of BTX were selected for physical assignment. We report an increase in marker density for BTX almost fourfold higher than previously reported (Ponce de Le6n et al 1996;Yeh et al 1996), construction of a male-specific linkage map, and four physical assignments of BTXlinked loci that confirmed coverage. These results offer a comprehensive map of BTX that will ultimately enhance QTL analysis of this chromosome.…”

“…In constrast, fluorescent in situ hybridization (FISH) with a bovine Y Chr specific paint suggested the bovine PAR was located at Xq4 (Ponce de Le6n and Carpio 1995). This reorientation of the PAR was subsequently supported by assignment of INRA030 to Xq42-ter, a heterozygous locus closely linked to TGLA325 on the two most recent linkage maps of BTX (Ponce de Le6n et al 1996;Yeh et al 1996). The human and bovine X Chr are estimated at approximately 150 cM (Hamden and Klinger 1985).…”

“…Methods used to obtain ms markers from M13 bacteriophage libraries (BM and BMS series) and genomic lambda clones (BL series), have been described previously Stone et al 1995;Smith et al 1996b). Preparation of the BTXp mierodissected library and ms identification from the BTXp library were as described (Ponce de Le6n et al 1996), with some modification. BTXp lambda clones were screened with a (GT)xl radiolabeled probe at high stringency conditions (65~ as described , and sequenced according to the manufacturer's protocol (Sequenase, U.S. Biochemicals, Cleveland, Ohio).…”

“…A more efficient strategy of obtaining chromosome/region-specific markers is to screen libraries containing small DNA inserts microdissected and microcloned from metaphase chromosomal spreads (Ludecke et al 1989). Microdissected libraries have increased marker density in specific genomic regions for a number of species (Greenfield and Brown 1987;Weber et al 1990;Fiedler et al 1991;Bahary et al 1993;La Pillo et al 1993;Seki et al 1993;Kobayashi et al 1995;Ponce de Le6n et al 1996).…”

A presentation of the differences between the sheep and goat genetic maps

“…1). Other features of gross chromosomal morphology, such as the architecture of the X chromosome and that of OAR 9/CHI 14, are similar for sheep and goats, but differ from cattle [7,11,14,17,22,27]. The similarity between the goat and sheep karyotypes is further evidenced by reports of natural matings between rams and does producing hybrid offspring, with at least one instance of such a mating generating a female offspring that was shown to be fertile when mated to a ram [16,24,25].…”