Taxonomy of Finfish (1+2)

6.1.6 Fish Chromosomes and Karyotypes

Fish chromosomes and karyotypes of the economically important species karyotype data are available nearly exclusively for freshwater groups such as acipenserirds, salmonids, cyprinids, cichlids and several others: marine important species are cytogenetically unexploited.

The 2n values in fishes range from 16 in anabatoid fish, Sphaerichthys osphromenoides to about 240 in Acipenser but range between 40 and 60 in most (80%) species investigated so far. The karyotypes with high chromosome numbers of about 100 and 150, respectively, occur in fish groups of polyploid origin such as acipenserids, salmonids, cyprinids, catastomids and cobitids.

No generalization can be made onkaryotype structures of fishes; many groups have very similar karyotypes (e.g.acipenserids, anguilids, poeciliids, many perciform group, etc) while other havehighly diversified karyotypes (e.g. salmonids, cyprinodontids, etc). Chromosomes of fishes are relatively very small as compared to chromosomes of mammals orfrogs through several groups (salmonids diproans) have chromosomes as large oreven larger as mammals.