Insect Molecular Markers and its Utility-A Review

Insects represent a major life form on earth. Nearly one million insect species have been discovered which comprises 75% of all the recorded animal species. This biological success is accredited to the enormous diversity of their size and body structure, mating strategies, and the incredible feeding and adaptation behaviour. Significant progress has been made in understanding insect diversity and ecology by using classical genetic principles. Over the last past 15 years, DNA markers have made a significant contribution in molecular studies on genetic relatedness, phylogeny, population dynamics and genome mapping in insects. A brief account of DNA based marker systems, their utility in entomological research, with examples wherever available is presented to prompt further reading and applications. The techniques described include restriction fragment length polymorphisms (RFLPs), randomly amplified polymorphic DNAs (RAPDs), amplified fragment length polymorphisms (AFLPs), microsatellites/simple sequence repeats (SSRs), and expressed sequence tag (EST) based marker system, single nucleotide polymorphisms (SNPs) and other derived marker systems along with their genetic nature and relative comparison. Although a large number of samples can be analyzed quickly, a number of other factors such as cost, speed and requirement of technical skills are the major concern. In this review, we hope to inform the general reader about the importance and scope of the main molecular markers commonly in use, along with brief details of some other techniques which show great promise for entomological studies. Thereafter, we discuss their applications including suitability for particular studies, the reliability of particular techniques, the issues of safety involved, cost effectiveness and the statistical analyses utilized.