The linkage map of sheep Chromosome 6 compared with orthologous regions in other species

Abstract

The genetic linkage map of sheep Chromosome (Chr) 6 has been extended to include 35 loci with the addition of 11 RFLP and 12 microsatellite loci. The sex-averaged linkage map now spans 154 cM from phosphodiesterase cyclic GMP beta polypeptide (PDE6B) to OarCP125, an anonymous sheep microsatellite. The male and female map lengths, at 180 cM and 132 cM respectively, did not differ significantly. The physical assignment of PDE6B to Chr 6q33-qter orientates the linkage map on sheep Chr 6 with PDE6B near the telomere and OarCP125 towards the centromere. The order and genetic distances between loci are similar for the sheep Chr 6 and cattle Chr 6 maps, except for the position of the casein genes. The sheep Chr 6 linkage map is also comparable to portions of human Chr 4, mouse Chrs 5 and 3, and pig Chr 8. The synteny between sheep Chr 6 and human Chr 4 has been extended from PDE6B (4p16.3) to epidermal growth factor (EGF, 4q25-q27). However, a region from platelet-derived growth factor receptor alpha polypeptide (PDGFRA) to bone morphogenetic protein 3 (BMP3), which spans 19 cM on sheep Chr 6, appears to be inverted with respect to the human and mouse loci. Other differences in the gene order between sheep, pig, and mouse suggest more complex rearrangements.

An Enhanced Linkage Map of the Sheep Genome Comprising More Than 1000 Loci

“…construction of low-density autosomal and X chromosome linkage maps (Crawford et al 1995;Broom et al 1996;Galloway et al 1996;Lord et al 1996;McLaren et al 1997;de Gortari et al 1998). For livestock species, such as sheep and cattle, where the costs of rearing and trait evaluation are high relative to the costs of typing a marker (100-1000 : 1), it has been estimated for quantitative trait loci (QTL) studies and genome scans that the optimum spacing between markers lies between 10 and 30 cM (Darvasi and Soller 1994).…”

Genes controlling ovulation rate in sheep

“…3) (Lord et al, 1998). Genes located on sheep chromosome 6 map to human chromosome 4 (Lanneluc et al, 1996;Lord et al, 1996). There is a large inversion in gene order between sheep chromosome 6 and human chromosome 4 near the region of the FecB locus (Lord et al, 1996).…”

“…Genes located on sheep chromosome 6 map to human chromosome 4 (Lanneluc et al, 1996;Lord et al, 1996). There is a large inversion in gene order between sheep chromosome 6 and human chromosome 4 near the region of the FecB locus (Lord et al, 1996). The breakpoint for one end of the inversion has been mapped to a small region of 150 kb pairs between the genes for SPP1 (secreted phosphoprotein 1) and DMP1 (dentin-specific acidic phosphoprotein) (Lumsden et al, 1999) outside the critical region for the FecB locus.…”

“…However, the total number of antral follicles (у 1 mm diameter) was found to be greater in adult I+ ewes than in ++ ewes (Shackell et al, 1993;McNatty et al, 1995b). This difference was due to the presence of more small antral (Lord et al, 1996;Lumsden et al, 1999) showing the location for the FecB locus together with the major phenotype for heterozygous (B+) and homozygous (BB) carriers of the mutation. Gene loci are shown in blue and microsatellite markers in black.…”

Screening of seven microsatellite markers for litter size in Xinong Saanen dairy goat

“…According to the comparative genomics, 5 microsatellite loci OarAE101, BM1329, OarHH55, BM143, BMS2508 (Lord et al, 1996;Vaiman et al, 1996;Ihara et al, 2004) that are linked to the fecundity gene FecB in the sheep, also in goat and cattle chromosome 6, microsatellite locus OarAE129 at goat chromosome 7 (Penty et al, 1993;Vaiman et al, 1996) and OarFCB11 at goat chromosome 2 (Vaiman et al, 1996) which are closely associated with the high reproduction trait in sheep were selected to obtain useful molecular markers for Xinong Saanen dairy goats selection and breeding through markers-assisted selection (MAS).…”