SHEEP LINKAGE MAPPING - RFLP MARKERS FOR COMPARATIVE MAPPING STUDIES

Restriction fragment length polymorphisms (RFLPs) detected using cDNA probes for conserved genes provide an important set of markers that an chor or link syntenic groups in a range of divergent mammalian species . DNA probes from sheep, cattle, pig, human and mouse were screened ag ainst sheep DNA samples and 24 new RFLP markers for sheep were identif ied. Among the loci tested, 22 had a homologue that has been mapped in humans. An RFLP for fibronectin (FN1) was linked to alpha-inhibin (IN HA) at a distance of 5cM. The FN1 locus has been assigned to sheep chr omosome 2q41-q44 and linkage between FN1 and INHA assigns INHA to the same chromosome in sheep. In addition to the new loci reported here, 2 8 RFLPs have been published previously by this group and these are col lated together with RFLPs published from other laboratories. RFLPs hav e been reported for 86 loci in sheep. Fifty-four loci have been mapped to 16 different chromosomes.