Chromosome Samples Preparation and Karyotype Analysis of Pomfret (Pampus argenteus)

Abstract:

In order to protect the germplasm resources of pomfret (Pampus argenteus) and provide some theoretical basis for its genetic breeding, this research was carried out by thermal titration method for preparing chromosome specimens of pomfret in living state and analyzed its chromosome karyotype. Finally, the evolutionary taxonomy of pomfret had been preliminary discussed. The pomfret involved in this experiment were juveniles 70-80 days old and their sizes ranged in 7.0–9.0 cm. They were divided into three groups, each group of three fishes, and kept in seawater containing 0.005% colchicine for 4 hours. Then, each group took three individuals, and a part of the gill tissues were sheared for preparing the chromosome specimens. The methods in this experiment prevented the pomfret from the physical damage caused by the operations off the water and ensured the experimental materials were obtained from pomfret with normal vitality. The analysis of chromosome karyotype showed that there were 48 telocentric chromosomes in the diploid and their karyotype formulae is 2n = 2SM + 10ST + 36T, namely, there were one pair of submetacentric chromosomes (SM) and 5 pairs of acrocentric chromosomes (ST) and 18 pairs of telocentric chromosomes (T), and their fundamental number (NF) was 50. There was no visible evidence of polyploidy chromosome and sex chromosome. and the karyotype was in accordance with the typical characters of karyotype in the higher group of fish evolutionary taxonomy. As the research objects were juveniles which had the immature sexual gland, and were unable to distinguish between male and female, it is uncertain whether there is a sexual chromosome in pomfret, and it needs to be further studied when the gonads are ready.