Sequence homology in the single-copy DNA of salmon

Abstract

1. 1. The hydroxyapatite reassociation kinetics of coho and sockeye DNA at a fragment length of 450 bp have been determined and compared with chum salmon. 2. 2. All three species have approx 60% of the genomic DNA in reiterated sequences with repetition frequencies that range from tens to thousands of times per genome. 3. 3. Single-copy DNA at a fragment length of 275 bp was prepared from chum salmon and labeled with 125I. 4. 4. 93% of the reactable [ 125I]DNA hybridized with an excess of coho DNA with second-order reaction kinetics. 5. 5. 73% of the reactable chum single-copy [ 125I]DNA hybridized with an excess of sockeye DNA. 6. 6. The denaturation temperature of chum single-copy [ 125I]DNA hybridized with either coho or sockeye DNA was depressed 2°C from that of the homologous duplex.