Molecular cloning of three major sequence species from Rainbow trout protamine mRNA

Double stranded cDNA molecules complementary to purified Rainbow trout protamine mRNA have been cloned in the bacterial plasmid pBR322. In order to circumvent the problems associated with a heterogeneous cDNA probe when identifying recombinants, a comparative hybridisation technique was used which can resolve between closely related cloned sequences. Using this technique, selected recombinants were shown to carry sequences corresponding to separate major fractions of protamine mRNA. Partial nucleotide sequences of the inserts in two clones confirms this conclusion.