Chromosome preparation and karyotype analysis of gynogenetic diploid and haploid of Ruditapes philippinarum

Gynogenesis is an important breeding method for rapid establishment of pure lines. Karyotype analysis of gynogenetic offspring of Ruditapes philippinarum has not been reported. In order to clarify the karyotype of gynogenetic diploid, haploid and normal diploid of R. philippinarum. In this experiment, the gynogenetic diploid, haploid and normal diploid larvae of R. philippinarum were selected. The chromosome drops were made by hot drop method, and the number of chromosomes was counted and karyotype analysis was carried out. The results showed that the number of chromosomes in gynogenetic diploid and normal diploid of R. philippinarum was 38, and the haploid was 19. The results of karyotype analysis showed that the karyotype formula of gynogenetic diploid and normal diploid of R. philippinarum was 2n=18m +20sm, NF=76, and the haploid karyotype was n=9m+10sm, NF=38. No sex chromosome and satellite were found in chromosome morphology. Studies have shown that clams have only two types of chromosomes, m and sm. The karyotype of gynogenetic diploid is the same as that of normal diploid, and the type of haploid chromosome is the same as that of normal diploid and the number is half of that of diploid. In this study, the metaphase division phase and karyotype analysis results of gynogenetic diploid, haploid and normal diploid of R. philippinarum were obtained by hot drop method using the trochophore larvae of R. philippinarum as materials, which enriched the related research of gynogenetic and haploid chromosomes of R. philippinarum and the cognition of chromosome number and karyotype composition of R. philippinarum. At the same time, it has important reference value for the study of cytogenetics and genetic breeding of R. philippinarum.