A COMPARISON OF SOLUTION AND MEMBRANE-BOUND DNA X DNA HYBRIDIZATION, AS USED TO INFER PHYLOGENY

A new method of membrane-bound DNA x DNA hybridization was devised to accommodate the study of small quantities of DNA obtained from museum specimens for phylogeny reconstruction. Membrane-bound, single-strande d target genomic DNAs were competitively hybridized with a total genom ic DNA probe to form hybrid duplexes required for the DNA dissociation experiments. We compared the thermal elution profiles derived from di ssociating duplexes made with probes of whole genomic, single-copy, an d repetitive DNA, as well as solution DNA x DNA hybridization using sc tracer. Quantitatively, pairwise indices of genetic distance derived from duplexes made with genomic probes depended entirely on hybridizat ion of repetitive sequences, but a parallel set of experiments using r epetitive and sc probes produced qualitatively similar results. The in dices of genetic distance generated by the membrane-bound hybrids form an internally consistent, resolved tree which is in agreement with th e solution DNA x DNA hybridization trials and traditional views of the phylogeny of the taxa under study.