Isozymes in population genetic studies

Abstract

There are several advantages of isozymes in genetic studies: (a) Alleles can be directly marked; (b) A gene can be detected even if it does not vary; (c) Large numbers of single gene characters can be measured in the same individuals; (d) Most banding patterns are inherited codominantly.

Consequently, isozyme studies play a major role in population studies, in evolutionary biology, in plant breeding and in conservation genetics. Knowledge of the genetic structure of natural populations is mainly based on isozyme analyses. The influence of mating systems, gene flow events and evolutionary history of populations are some of the fields of special interest. In the course of molecular evolution, gene duplications and the evolution of multigene families are a major issue. The easiest way to trace gene duplications is by isozyme studies, especially in plants, where polyploidization is common. In general, molecular characterization of the genome by isozymes allows for the identification of genetic traits within and between populations. Furthermore, heterozygotes can easily be sorted out from homozygotes. This provides a tool for plant breeding programs and identification of cultivars. The genetic erosion of natural populations threatens our natural resources. Sound conservation programs are therefore necessary to prevent the genetic depauperisation. This, however, requires knowledge of the genetic structure of natural populations. Isozymes may play a major role in resource management and resource exploration.