Rapid communication: variable number of tandem repeat marker, RVF9303, in rainbow trout.

Polymorphism. A variable number of tandem repeat (VNTR; Nakamura et al., 1987) polymorphism was detected in rainbow trout (Oncorhynchus mykiss Walbaum) using MspI and BgZII. The probe, RVF9303, 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 MspI or BgZII were prehybridized in 7% PEG, 10% SDS, and 200 pg/mL of sheared 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 a t 65°C overnight. The filters were washed in 2x SSC for 15 min a t room temperature and in . lx SSC/.l% SDS for 20 min at 65°C. Description of Polymorphism. Four bands were detected using MspI and BgZII. Allele sizes (and frequencies) for MspI were 5.5 kb (.2 1, 9.0 kb (. 11, 9.5 kb ( . l ) , and 16.0 kb (.6) (Figure 1). Allele sizes (and frequencies) for BgZII were 18.0 kb ( . 2) , 20.0 kb (.l), 22.0 kb ( . l ) , and 25.0 kb (.6). Heterozygosity was 80.0%. Frequencies were estimated using five unrelated rainbow trout. Inheritance Pattern. Codominant inheritance of the MspI and BgZII alleles was demonstrated in two rainbow trout parents and their 16 offspring. Probe Availability. The probe is available from N. Okamoto.