Genetic linkage between the bovine plasma protease inhibitor 2 (Pi-2) and S blood group loci

The bovine gene map

The present status of the bovine gene map as well as some of the methods and strategies important for future efforts in completing the gene map of cattle are reviewed.

Linkage of bovine erythrocyte antigen loci B, C, L, S, Z, R' and T' and the serum protein loci post-transferrin 2 (PTF 2), vitamin D binding protein (GC) and albumin (ALB) to DNA microsatellite markers

Seven bovine erythrocyte antigen loci and three serum protein loci were tentatively assigned to chromosomes or synteny groups by linkage analysis to previously assigned microsatellite DNA markers. The erythrocyte antigen locus EAB was mapped to synteny group U27; EAC to chromosome 18, synteny group U9; EAL to chromosome 3, synteny group U6; EAS to chromosome 21, synteny group U4; EAZ to chromosome 10, synteny group U5; EAR' to chromosome 16, synteny group U1; and EAT' to chromosome 19, synteny group U21. The vitamin D binding protein (GC) and albumin (ALB) loci were assigned to chromosome 6, synteny group U15 and post-transferrin 2 (PTF 2) to chromosome 19, synteny group U21.

Linkage relationships among 20 genetic markers in cattle. Evidence for linkage between two pairs of blood group systems: B-Z and S-F/V respectively

Five bovine paternal half-sib pedigrees for a total of 527 individuals were typed for six blood group systems: A, B, F/V, L, S, Z; for nine biochemical polymorphisms: ADA, MPI, PGM-3(slow), NP, Gc, Pi2, Tf, Ptf1 and Ptf2; and for restriction fragment length polymorphisms at five autosomal loci: Tg, GH, LDLr, BoLA-DQ and BoLA-DY. Two of the pedigrees were informative for segregation at the 'muscular hypertrophy' locus, and one was informative at the coat colour determining 'roan' locus. Linkage analysis was performed between all markers. Linkage was demonstrated between the S and F/V blood group systems (z = 3.11), adding one locus to the previously identified linkage group VII (LGVII) [Pi-2 and S], the most likely order being Pi2-S-F/V with maximum likelihood recombination rates of 0.208 and 0.211. Also shown to be linked were the blood group systems B and Z (z = 5.7, theta = 0.245). We confirmed the observation previously made by Andersson et al. (1988) of a high recombination rate between class II genes DQ and DY, suggesting either a larger physical distance between those genes than expected from comparative data, or the presence of a 'recombinational hotspot' in the bovine major histocompatibility complex. No linkage was found either with the 'muscular hypertrophy' locus, or with the 'roan' locus. However, these two loci could be excluded from respectively 1.7 and 2.5 Morgans of the bovine genome.