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 thynnu s 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%to3.3%, 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.

Constructing Genetic Linkage Maps Using the Whole Genome Sequence of Pacific Bluefin Tuna (<i>Thunnus orientalis</i>) and a Comparison of Chromosome Structure among Teleost Species

“…The karyotype composition of Pacific bluefin tuna was two pairs of metacentric, three pairs of submetacentric, two pairs of subtelocentric, and 17 pairs of acrocentric chromosomes. The numbers of linkage groups on the sex-specific maps agreed with the number of chromosome pairs suggested from microscopic observations [9]. Scaffolds integrated with linkage groups will have to be detected on chromosome samples using fluorescence in situ hybridization to reveal the relationships between linkage groups and chromosomes, as in other fish [12] [36].…”

“…Cytological studies [9] [10] have reported that Thunnus species have 24 pairs of chromosomes. Draft genome sequence when merged should, therefore, only have 24 huge fragments corresponding to each chromosome.…”

Chromosomal evolution in large pelagic oceanic apex predators, the barracudas (Sphyraenidae, Percomorpha)

“…Large pelagic fishes, such as species of Sphyraena, are important models in the investigation of chromosome evolution in migratory marine species. The cytogenetic patterns of Sphyraena species are similar to those of other large pelagic migrators, such as some representatives of Scombroidei (Ida et al, 1993;Soares et al, 2013), exhibiting various basal characteristics. By contrast, population groups dependent on particular ecological regions and low vagility may be more susceptible to population stratification and fixation of particular karyotypic patterns (Molina and Galetti, 2004;Molina, 2007).…”

Karyotypes of three species of the family Cottidae (Scorpaeniformes)

“…Ida and Yunokawa, (1980) examined 5 species in the family Platycephalidae and also found the new arm number to be 48. Ida et al (1982Ida et al ( , 1989 later examined 8 species of Sebastes (Scorpaenidae) and 4 species in the family Cottidae, finding the new arm number to be 48 in all the species. Thus most species in the order Scorpaeniformes have a new arm number of 48.…”