Chromosomes of the bowhead whale (Balaena mysticetus linnaeus)

Abstract

The somatic chromosomes of the bowhead whale, Balaena mysticetus, are described for the first time using homogeneous staining and trypsin G-banding. The diploid chromosome number in all cells studied is 42. The bowhead karyotype retains many features of the general 2n = 44 cetacean karyotype from which it is derived, yet it is the first mysticete for which a chromosome number other than 2n = 44 has been reported. The advanced karyotype of the bowhead may reflect greater anatomical specialization of this whale than of other mysticetes. Cytogenetic data for cetaceans are reviewed within the framework of a model of speciation in sympatry.