GENETIC-VARIATION IN THE AFRICAN RODENT SUBFAMILY OTOMYINAE (MURIDAE)- IMMUNO-ELECTROTRANSFER OF LIVER PROTEINS OF SOME OTOMYS IRRORATUS (BRANTS 1827) POPULATIONS

Liver homogenates from 12 populations of the vlei rat Otomys irroratus (Brants 1827) were subjected to Sodium Dodecyl Sulfate Polyacrylamide electrophoresis on 7-17% gradient gels followed by Western blotting. Detection of antigenic proteins was carried out with an antiserum agai nst liver proteins of one of these populations. Blots thus obtained we re digitized into computer images and the gray level values of all ele ctromorphs were recorded. A matrix of these values was then constructe d and subjected to statistical analyses (discriminant function and clu ster analysis by the Unweighed Pair Group Method with Averages). Boot- strapping parsimony analysis was performed on st multistate character matrix derived from the gray level data. Although immunoblotting seeme d to be sufficiently sensitive to detect extensive individual variatio n, there was only partial agreement between the dendrograms thus gener ated and the trees previously obtained from chromosome studies (CONTRA FATTO et al. 1992b)). Evolutionary implications of the findings are di scussed and it is concluded that lack of congruence is most Likely due to the detection, by this method, of old synapomorphies which pre-dat e the establishment of chromosomally defined groups of this species. T his is taken as confirmation of a hypothesis which suggests that speci ation can occur by chromosomal rearrangements before gene mutations, u sually associated with speciation, become established.