Rapid communication: variable number of tandem repeat marker, RVF9401, in rainbow trout.

Polymorphism. A variable number of tandem repeat (VNTR; Nakamura et al., 1987) polymorphism was detected in rainbow trout (Oncorhynchus rnykiss Walbaum) using BgZII. The probe, RW9401, was isolated from a genomic DNA cosmid library developed from the RTG-2 cell line (Wolf and Quimby, 1962). Method of Detection. Nylon filters containing rainbow trout genomic DNA digested with BgZII were prehybridized in 7% PEG, 10% SDS, and 200 pg/mL of sheai-ed rainbow trout sperm DNA at 65°C overnight. Random-primed labeled probe (1.5-2.0 x lo6 cpm/mL) was added to 5 mL of the prehybridization solution and the filters hybridized in this solution at 65°C overnight. The filters were washed in 2x SSC for 15 min at room temperature and in .lx SSC/.l% SDS for 20 min at 65°C. Description of PoZymorphism. Three bands were detected using BgZII. Heterozygosity was 62.5%, with observed allele sizes (and frequencies) as follows: 6.2 kb (.56), 6.6 kb ( . 2 5 ) , and 7.0 kb (.19). Frequencies were estimated using eight unrelated rainbow trout. Inheritance Pattern. Codominant inheritance of the three alleles was demonstrated in two rainbow trout parents and their 16 offspring (Figure 1). Probe Availability. The probe is available from N. Okamoto.