Molecular marker systems with special reference to the Silkworm Bombyx mori L.

Abstract

Study on genetic diversity is critical to success in any crop breeding and it provides information about the quantum of genetic divergence and serves a platform for specific breeding objectives. Genetic diversity is a particular concern because greater genetic uniformity in silkworm can increase vulnerability to pests and diseases. Hence maintenance of genetic diversity is a fundamental component in long term management strategies for genetic improvement of silkworm which is cultivated by millions of people around the worlds for its lustrous silk. In view of the present study, genetic diversity studies carried out in silkworm using divergent methods (Quantitative traits, biochemical and molecular markers) and present level of diversity, pertaining to the literature has been reviewed. Genetic diversity is the genetic variation within species, both among geographically separated populations and among individuals within a single population. Genetic diversity is an essential aspect in conservation biology because a fundamental concept of natural selection states that the rate of evolutionary change in a population is proportional to the amount of genetic diversity present in it. Decreasing genetic diversity increases the extinction risk of populations due to a decline in fitness. Therefore, both biochemical and molecular markers have recently been employed to estimate the extent of genetic diversity present among various types of silkworm strains such as mono-, bi and multivoltines present in China, Japan, Korea, India, and several other countries.