几种鲟鱼基因组大小、倍体的特性及鲟形目细胞进化的探讨

采用Ｆｅｕｌｇｅｎ－显微分光光度计方法，以鸡红细胞为标准ＤＮＡ（３．２２ｐｇ／２Ｃ）测定了长江白鲟、达氏鲟、中华鲟、史氏鲟和北美匙吻鲟的体细胞基因组大小（ＤＮＡ含量）。结果表明，上述五种鲟鱼ＤＮＡ含量分别为４．１１、８．２６、９．０７、６．０７和３．９６ｐｇ。长江白鲟和北美匙吻鲟均属于四倍体鱼类，分布在长江水系的中华鲟和达氏鲟两种鲟属鱼类为八倍体类型。史氏鲟初步判断为八倍体，据分析可能存在四倍体的

GENOME SIZE,PLOIDY CHARACTERS OF SEVERAL SPECIES OF STURGEONS AND PADDLEFISHES WITH COMMENT ON CELLULAR EVOLUTION OF ACIPENSERIFORMES

Using of DNA of chicken erythrocyte (3. 22pg/2C) as a standard, genome size (somatic nuclear DNA content) of five species of sturgeons and paddlefishes including Chinese paddlefish (Psephurus gladius ), Yangtze sturgeon (Acipenser dabryanus ), Chinese sturgeon (A. sinensis ), Amur sturgeon (A. schrenckii ) and American paddlefish (Polyodon spathula ) were determined by microspectrometry. The DNA contents of each said species were 4. 11, 8. 26, 9. 07, 6. 07 and 3. 96pg, respectively. The genome size of two species including Yangtze sturgeon and Chinese sturgeon, was found two times as big as that of Chinese paddlefish and American paddlefish. Obviously, Chinese paddlefish and American paddlefish belong to the tetraploidy group whereas Yangtze sturgeon and Chinese sturgeon are octoploids. According to the present results and data reported, Amur sturgeon is possibly an octoploid (8n), however, it is more likely that two or more kinds of polyploids (4n, 8n and so on) have existed in the species of Amur sturgeon. Combination of the present results and data reported among Acipenseriformes including two families and six genera, the genus Acipenser possessed 4n. 8n. 12n and 16n while the other five genera possessed only 4n. It is deduced that the polyploidization took place at early time of formation of Acipenseriformes and within the genus Acipenser. Polyloidization has played an important role in the diversity of Acipenser which has more than 65% species in Acipenseriformes.