Applications of molecular tools in systematics and population genetics of lobsters

Abstract

Recent advances in molecular tools have facilitated the detection of new species, differentiation of cryptic species, revision in taxonomy, assessment of evolutionary relationships, phylogenetic analysis, phylogeography and stock delineation studies in marine lobsters. This chapter discusses the implications of these tools in lobster research through a comprehensive review of the works carried out globally across different species. The use of molecular markers for resolving conflicting issues in phylogeny and evolution of marine lobsters has been detailed at the beginning of this chapter. An account on the application of ‘DNA barcoding’ for species and larval identification of lobsters and use of multiple genes in their phylogenetic systematics as well as distinction of lineages is described afterwards. Mitochondrial genomes have been utilised as a major genetic marker in many areas of research. The complete mitochondrial genome of various lobster species characterised so far is given for reference. Better knowledge on the diet of planktonic phyllosoma larvae of lobsters is important for commercialisation of lobster mariculture. Molecular diet analysis of larvae utilising conventional markers and high-throughput DNA sequencing methods has been explained. Efforts to effectively manage a fishery require an understanding of population demographics and connectivity. By defining the scale of subpopulation structure shown by a species through genetic analysis, management units can be accurately identified. The stock delineation studies in lobsters using different types of molecular markers have been discussed in this chapter. DNA microsatellites are considered as a dominant class of markers in genomic analysis for assessing genetic structure of populations, linkage, parentage and relatedness. The use of highly polymorphic microsatellite markers with their application in diverse fields like detection of fine-scale genetic structure over small spatial scales for better management and their utility in assigning marine-protected areas (MPAs), parentage analysis, etc., are narrated. The application of gene sequencing and next-generation sequencing (NGS) derived markers in lobster research is detailed, and it is anticipated that these markers due to their improved analytical power and high precision will soon replace the mtDNA and microsatellite markers used in this field since 2004. The present scenario of lobster genetic research in India is reviewed at the end.