Taxonomy of Finfish (1+2)

6.1.4 Cytotaxonomy of finfishes

6.1.4 Cytotaxonomy of Finfishses

Karyotype analysis is the basic of cytogenetics. It involves the study of chromosome number, size and morphology at the metaphase stage. Karyotypes comprise a heritable character of each species for which it is useful in taxonomic differentiations between species. This is called as Cytotaxonomy. Karyotypes variation occurs in different evolutionary lineages due to chromosomal rearrangement, which should be useful in inferring the evolutionary inter-relationship between certain taxa. This is called as cytosystematics.

Fish cytogenetics has made its real beginning with the adoption of colchicines-citrate-air dry method developed by the mammalian cytogenetics in the 1960s, which replaced the slow and cumbersome techniques of chromosome study by tissue sectioning. The karyotypes of about 10% of the total icthyofauna are available so far in the literature. This has enriched the discipline of ichthyology particularly on the cytotaxonomic and cytosystematics aspects. The chromosome analysis is also useful in ploidy determination, species and hybrid identification and genotoxicity study of the pollutants.