【摘要】 本实验采用血涂片,Feulgen染色,显微荧光光度法对分属4目7科的14种淡水鱼的红细胞核DNA含量进行了初步测定。在这些鱼类中,二倍体染色体数目和DNA含量存在着明显的相关性:2n=50左右的类型的DNA含量大多在2.0—2.9微微克(pg);而2n=100的鲤鱼和泥鳅则具有相对高的DNA含量,分别为3.5和4.6pg。分类地位较高的黄鳝和乌鳢具有较低的DNA含量,分别为1.6和1.3pg。鲤科鱼类中,染色体数目2n=50和2n=48的两种类型并不存在一致性的显著差异,这可能反映了这两类核型在进化上的近缘程度。泥鳅的DNA含量大约是大鳞付泥鳅的DNA含量(2.2pg)的2倍,证明了泥鳅是一种四倍体类型的鱼。更多还原

【Abstract】 The diploid DNA content of 14 species of fresh-water fishes belonging to 7 families in 4 orders was measured with fluorescence microphotometry after Feulgen staining.These fishes,comprisiong Ctenopharyngodon idellus,Megalobrama amblycephala,Hypophthalmi-chthys molitrix,Paracanthobrama guichenoti,Pseudorasbora parva,Sarcocheilichtkys nigri-pinnis nigripinnis,Cyprinus carpio,Misgurnus anguillicaudatus,Paramisgurnus dabryanus,Pseudobagrus fulvidraco,Parasilurus asotus,Monopterus albus,Tilapia nilotica and Ophioce-phalus argus,were collected from the Long Lake and the experimental fish pools of the Yangtse River Fisheries Institute in Shashi district of Hubei Province.The results we obtained indicate that there is a close correlation between chromosome number and DNA content in these fishes.The DNA content of the species with about 2n= 50 ranges from 2.0 to 2.9 picograms (pg) in general,while C.carpio and Af.anguillicaudatus with 2 = 100 possess a higher DNA content,that is,3.5 pg and 4.6 pg respectively.The more specialized or evolutionarily advanced species such as Af.albus and O.argus,however,have less DNA content than the more generalized ones.No consistent difference in DNA value exists between the two forms with 2 = 48 and 2=50 in cyprinid fishes,suggesting these two kinds of karyotypes might have a closer relationship in evolution.In all probability,Af.anguillicaudatus represents a tetraploidy state in relation to P.dabryanus,since the DNA content of the former is twice as much as that of the latter.更多还原