Taxonomy of Finfish (1+2)

6.1.3 Chromosome Classification by Centromeric Position

Type	Centrometric position	Symbol	Centrometric index range
Metacentric	Nearly median	m	46-49
Submetacentric	Submedian	sm	26-49
Acrocentric	Subterminal	st	15-30
Telocentric	Terminal	t	<15

The chromosomes of a species can be arranged in order of size (by counting from the microscopic photograph or camera lucida drawing). The complete set of chromosomes arranged according to their size is called as karyotypes. Karyotype of different species differ in size, shape, and number of chromosomes. It is, thus a phenotypic character similar to other morphological traits like body size. Therefore, it is believed that the karyotypes in different species have evolved through natural selection. Within a species, the males and females may have minor dissimilarity in the karyotypes, generally in a pair of chromosomes are very much similar are called as autosomes.