【摘要】 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类型。根据所得到的结果并结合已发表的DNA含量和染色体资料，分析了鲟形目鱼类在细胞遗传上的进化特点。鲟形目鱼类全为多倍体起源的鱼类，在鲟形目的两科（白鲟科和鲟科）六个属中，除鲟属外，其他五个属均为四倍体，而鲟底已发现有四倍体、八倍体、十二倍体和十六倍体。说明在细胞水平的染色体加倍与鲟形目鱼类各科、属分化没有直接联系，只在鲟形目形成的早期和鲟形目形成后的鲟属种间分化中扮演着重要角色。鲟底鱼类的染色体剧烈分化可能是造成现今鲟属种类数最多（占整个鲟形目鱼类的65％以上）的重要原因。更多还原

【Abstract】 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.更多还原