MINISATELLITE DNA MARKERS IN THE CHICKEN GENOME .2. ISOLATION AND CHARACTERIZATION OF MINISATELLITE LOCI

The isolation of chicken minisatellites is reported. Two charomid libr aries were constructed from fractions of size-selected MboI-digested g enomic DNA. A total of 5985 colonies were screened with the multilocus probes 33.6 and 33.15; 137 positives were obtained (2.35%). A total o f 55 clones were tested against four unrelated chickens; 30 revealed v ariable single locus patterns. More detailed characterization was made of 15 probes, which were tested against four families comprising a to tal of 53 offspring. Of parent/offspring comparisons 51% were informat ive for segregation. No mutations were detected. Three minisatellites were linked on the same autosome, implying that these loci may occur i n clusters, and one was Z chromosome-linked. Heterozygosity and alleli c variability were measured in 67 individuals from several different s trains and breeds. Mean heterozygosity ranged from 50 to 84%. Minisate llite loci appear to be highly variable in the chicken and should prov ide highly informative markers in intraspecific crosses in genome mapp ing studies.