Karyotypes and Cellular DNA Contents of Three Species of the Family Scombridae from Japan

Abstract

Three species of the family Scombridae, viz. Auxis thazard, Katsuwonus pelamis, and Thunnus thynnus were studied for their karyotypes and cellular DNA contents. The first species is unknown as to its karyotypes or its cellular DNA content, which are described below. The diploid number of these three species is invariably 48, and composed of acrocentric chromosome in Auxis thazard and Katsuwonus pelamis, but in Thunnus thynnus the karyotype is composed of one pair of metacentric, two pairs of subtelocentric, and 21 pairs of acrocentric chromosomes. The DNA contents are 1.8pg/cell in Auxis thazard and 2.00pg/cell in Katsuwonus pelamis, these values are being included in the range of typical ones as members of the teleost group. Relative chromosome size ranges from about 1.2% to 3.3%, showing almost unimodal composition in size. The karyotypes of these three species of the family Scombridae are characterized by a smaller variability in size of chromosomes. © 1993, The Japanese Society of Fisheries Science. All rights reserved.