Cloning and genetic variability of a HindIII repetitive DNA in Acrossocheilus paradoxus (Cyprinidae)

Thirty clones of a highly repetitive HindIII fragment of DNA from seven pop ulations of Acrossocheilus paradoxus (Cyprinidae) were isolated and sequenc ed. The fragment represents a tandemly repeated sequence, with a monomeric unit of 270 bp, amounting to 0.08-0.10% of the fish genome. Higher units of this monomer appear as a ladder in Southern blots. The HindIII satellite D NA family is conserved in three genera of the Cyprinidae. Variation in nucl eotide sequences of this repetitive fragment, which is A+T-rich, is distrib uted both within individuals and among populations. High overall nucleotide divergence (d(ij) = 0.056 +/- 0.001) was detected among clones of the Hind III satellite DNAs of Acrossocheilus paradoxus. Based on the molecular cloc k hypothesis, the maximum evolutionary rate was estimated to be 5.3 x 10(-7 ) substitutions per site per year. Lineage sorting may have contributed to the genetic heterogeneity within individuals and populations. Cladistic ana lyses indicated a closer phylogeographic relationship between populations o f the central and south regions in Taiwan.