【摘要】 <正> 团头鲂(Megalobrama amblycephala)自1960年开始试养,现不仅已在全国许多省市推广,而且也已移殖到国外。由于各地养殖场在进行人工繁殖时对亲鱼的选育注意不够,因而出现“退化“现象,目前提纯复壮、品种改良工作已逐步展开。团头鲂染色体的研更多还原

【Abstract】 Numbers of chromosome of mcyalobrama amblycephala Yih have been reported differently in papers published in recent years. Our observations of peripheral blood leukocytes collected from both sexes reveal:The diploid chromosome number is 2n=48.The karyotype consists of 8 pairs of metacentric chromosomes, 12 pairs of subme-tacentric chromosomes, 3 pairs of subtelocentric chromosomes and 1 pair of "special chromosomes". The "special chromosome pair" may consist of a pair of megachromo-somes in some individuals, or a pair of heteromorphic chromosomes--one megachro-mosome and one small chromosome-in others. The megachromosome or heterochro-mosome pair occurred in both sexes, obviously, they are not sex-chromosomes. The origin of the "special chromosome pair" is discussed.The secondary constrictions and satellites were only observed in some chromosomes of a few metaphase plates.更多还原