三倍体牙鲆的核型证明

KARYOTYPE EVIDENCES OF TRIPLOIDY IN THE LEFT-EYED FLOUNDER, PARALICHTHYS OLIVACEUS (T. & S.)

于1990，1993—1994年以捕自青岛近海的牙鲆亲鱼，采用冷休克法（0－4℃）进行多倍体的人工诱导实验，以期掌握牙鲆细胞遗传学特征和研究遗传育种方法。通过实验得到了三倍体牙鲆并进行培育。在原肠胚期采用空气干燥法、Giemsa染色获得正常二倍体、三倍体的染色体制片。镜检得，牙鲆二倍体染色体以2n=48，均为端部着丝点染色体，核型为24t，其管数NF=48；三倍体的染色体3n=72，也都为端部着丝点染色体，其臂数NF=72，并依据二倍体的枝型得出了三倍体的核型图。

Studies on triploidy induction in the left-eyed flounder, Paralichthys olivaceus (T. & S.) from the coast of Qingdao were carried out using cold-shock technique (0-4℃) in 1990, 1993 and 1994 in Qingdao. The triploid left-eyed flounder were obtained and cultured under normal conditions. This paper presents karyotype evidences of induced triploidy and diploid left-eyed flounder. Samples for chromo-some studies of diploidy and induced triploidy were prepared according to the rou-tine air-dried method and stained with a Giemsa solution. observation under micro-scope reveals that there are 48 chromosomes in diploidy which are acrocentric chro-mosomes and its karyotype formula is 24t, NF = 48, while in triploidy there are 72 chromosomes which are also acrocentric chromosomes and its arm number NF=72.The different chromosome numbers of diploidy in the left-eyed flounder obtained in this study were different from those of Nogosu (1960) and Sakamoto et al.(1980). We consider that there might be polymorphism in karyotypes of the left-eyed flounder due to the different geological populations. This study also showed that the early stage of triploidy in the left-eyed flounder could be identified very well in the gastrula stage and that its triploid karyotype is made on the basis of the diploid karyotype and the resources of chromosomes.