Genetic variation in the african rodent subfamily otomyinae (muridae): Immuno-electrotransfer of liver proteins of some otomys irroratus (brants 1827) populations

Abstract

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 against liver proteins of one of these populations. Blots thus obtained were digitized into computer images and the gray level values of all electromorphs were recorded. A matrix of these values was then constructed and subjected to statistical analyses (discriminant function and cluster analysis by the Unweighed Pair Group Method with Averages). Boot-strapping parsimony analysis was performed on a multistate character matrix derived from the gray level data. Although immunoblotting seemed to be sufficiently sensitive to detect extensive individual variation, there was only partial agreement between the dendrograms thus generated and the trees previously obtained from chromosome studies (CONTRAFATTO et al. 1992b). Evolutionary implications of the findings are discussed and it is concluded that lack of congruence is most likely due to the detection, by this method, of old synapomorphies which pre-date the establishment of chromosomally defined groups of this species. This is taken as confirmation of a hypothesis which suggests that speciation can occur by chromosomal rearrangements before gene mutations, usually associated with speciation, become established. © 1997 Taylor & Francis Group, LLC.