Comparative DNA/DNA reassociation kinetics in three hamster species.

1. Three major DNA repetition classes can be distinguished in the genomes of three hamster species Mesocricetus auratus, Cricetulus griseus, and Phodopus sungorus sungorus: A very fast reassociating fraction of about 13% of the DNA, a fast reassociating fraction comprising 10-23% of the DNA, and a slowly reassociating fraction containing single-copy sequences of 63-78% of hamster DNA. 2. In the DNA of the Syrian and Djungarian hamster 43%-53%, and in the DNA of the Chinese hamster 80% of the single-copy sequences are interspersed with repetitive sequences. 3. The lengths of repetitive DNA sequences, vary between more than 3 kb and 0.3 kb, with the majority of sequences having a length of 0.3 kb to 0.5 kb. 4. The findings suggest that the genomes of the hamster species studied are organized in a short period interspersion pattern. 5. Unlike other vertebrate and invertebrate genomes, moderately repetitive sequences exhibit a high degree of intraspecific homology in the hamster genome.