A MEDIUM DENSITY MICROSATELLITE MAP OF BTA10 - REASSIGNMENT OF INRA69

We have developed a genetic map of BTA10 based on 8952 informative mei oses for 13 microsatellite markers and the erythrocyte antigen Z. With the exception of OarAE64, the support for the order of all loci in th e map exceeded a LOD > 3.0. The length of the BTA10 genetic map was 87 .0 centimorgans (cM). The 14-marker, sex-average map in Kosambi cM was : 2-DIK20-3.0-EAZ-6.7-CSSM46-3.7-SRCRSP3-1.0-OarAE64 with an average i nterval of 6.70 cM. The microsatellite INRA69 was recently assigned to the pseudoautosomal region of the bovine X chromosome by linkage anal ysis. However, we found that twopoint support for linkage between INRA 69 and 15 X-linked bovine microsatellites was LOD < 0.50 in 529 recipr ocal backcross and F-2 fullsib progeny. We performed twopoint analyses of INRA69 against 275 markers distributed throughout the bovine genom e and found significant associations with a LOD > 3.0 only between INR A69 and eight BTA10 microsatellite loci. Consequently, we excluded INR A69 from the genetic map of the X chromosome and reassign this microsa tellite to BTA10.