Development of DNA fingerprint probes: An approach and its application

Abstract
Multi‐locus probes are of great potential for identification purposes, gene mapping and breeding programs in farm animals. However, the number of loci detected by the available multi‐locus probes is insufficient for any major mapping or breeding projects in most of the large farm animals such as cattle, sheep and horses. We present here the development of a multi‐locus probe for large farm animals by screening a bovine genomic library with multi‐locus and bovine genomic probes. This screening procedure was applied for the isolation of highly repetitive, highly polymorphic, non‐satellite sequences. The resulted microsatellite probe (R18.1) consists of seven 35bp repeat units, with a mean divergence of 15% between repeats, separated by poly(CA) sequences. Probe R18.1 hybridizes efficiently to digested DNA from poultry and sheep yielding highly polymorphic DNA fingerprint patterns. The rational by which this probe was developed is presented and discussed.