SATELLITE DNA REPEAT SEQUENCE VARIATION IS LOW IN 3 SPECIES OF BURYING BEETLES IN THE GENUS NICROPHORUS (COLEOPTERA, SILPHIDAE)

Three satellite DNA families were identified in three species of buryi ng beetles, Nicrophorus orbicollis, N. marginatus, and N. americanus. Southern hybridization and nucleotide sequence analysis of individual randomly cloned repeats shows that these satellite DNA families are hi ghly abundant in the genome, are composed of unique repeats, and are s pecies-specific. The repeats do not have identifiable core elements or substructures that are similar in all three families, and most inters pecific sequence similarity is confined to homopolymeric runs of A and T. Satellite DNA from N. marginatus and N. americanus show single-bas e-pair indels among repeats, but single-nucleotide substitutions chara cterize most of the repeat variability. Although the repeat units are of similar lengths (342, 350, and 354 bp) and A+T composition (65%, 71 %, and 71%, respectively), the average nucleotide divergence among seq uenced repeats is very low (0.18%, 1.22%, and 0.71%, respectively). Tr ansition/transversion ratios from the consensus sequence are 0.20, 0.6 9, and 0.70, respectively.