Biochemical genetics of some Indian fishes

Abstract

Studies on biochemical genetics of fishes, using electrophoretic methods, are relatively of recent origin. Earlier serum and eye lens protein were used to identify marine populations. This technique showed that closely related species have similarities in their protein make up, whereas these taxonomically apart showed striking differences. Thus, the usefulness of employing this method was clearly demonstrated in fish taxonomy. The study of genetic struture of fish populations through the analysis of enzyme polymorphism proved very promising. The advantage of isozyme technique was that genetic interpretations could be made directly from the raw data using simple genetic models. Using these tehniques genetic variations within Indian mackerel, the oil sardine, the grey mullets, the sciaenids and the promfrets were shown. The samples of these fishes were obtained from different locations of the marine environment. In addition to the genetic variation, genetic divergence among the species was also studied. The levels of genetic differentiation among the populations varied greatly. Probably these reflect the magnitude of gene flow among the populations. The differences recall the disparity in the spawning behaviour and modes of larval dispersal among the species. It is concluded that the methodology of biochemical genetics can be apllied to many areas of fisheries research with considerable success.