CHARACTERIZATION OF A MAJOR TANDEMLY REPEATED DNA-SEQUENCE (RBMII) PREVALENT AMONG MANY SPECIES OF WATERFOWL (ANATIDAE)

We have investigated the evolution of a 190 base pair tandemly repeated DNA sequence (RBMII) in 27 different species of waterfowl. In this paper we show that the RBMII sequence is present in many species belonging to 7 of the 11 Anatid tribes. Inter- and intra-tribal differences in repeat presence indicate that, although the RBMII sequence has been maintained among widely divergent species, it is rapidly evolving. Restriction enzyme analyses suggest very different hierarchical repeat organizations among different species. DNA sequence comparisons of 32 cloned monomer units from five different species revealed what appears to be a nonrandom distribution of sequence divergence, as well as large differences (up to 25-fold) in intraspecific sequence variation between relatively closely related species.