排序方式: 共有20条查询结果,搜索用时 31 毫秒
1.
To estimate the genetic diversity in the Yangtze finless porpoise ( Neophocaena phocaenoides asiaeorientalis), the randomly amplified polymorphie DNA technique was applied to examine ten animals captured from the Yangtze River. Out of 20 arbitrary primers used in the experiment, seventeen produced clearly reproducible bands. Calculated by Nei‘s formula d = 1-NAB/NT, the genetic distances ranged from O. 0986 to O. 5634. Compared with other cetacean populations, this genetic distance is quite low.Such a low genetic diversity suggests that this population may be suffering from reduced genetic variation,and be very fragile. More studies are needed for understanding the basis for this apparent low genetic diversity and to help protect this endangered, unique population. 相似文献
2.
3.
4.
5.
河豚与河鲀是两类不同的动物,这在科学分类上已有明确定论。河豚指哺乳动物纲鲸目河豚总科河豚科(淡水豚科)动物,如白鳍豚、扬子江豚等;营淡水生活;其中的白鳍豚是国家保护动物,不允许捕杀,更不存在加工利用问题;脏器无毒,不存在毒索之忧。河鲀指硬骨鱼纲纯形目纯总科鲀科鱼类(也有少数认为指鲀形目),生活于近海及河流入海口;有些种(如东方鲀属等)的脏器有毒,称河鲀毒素,可作医药之用,加之肉质鲜美,故有加工利用价值。 相似文献
6.
7.
Population Genetic Structure and Genetic Differentiation of the Pufferfish Takifugu Rubripes and Takifugu Pseudommus Revealed by RAPD Analysis 总被引:3,自引:0,他引:3
RAPD analysis is used to assay the population genetic structure and genetic differentiation of pufferfish T.rubripes and T.pseudommus.One hundred and twenty fragments are aplified with 21 random sequence 10-mer primers.The proportion of polymorphic fragments of T.rubripes populations from the coast of China(TRC),the coast of Japan(TRJ),general population of T.rubripes both from China and Japan(TRCJ),and the population of T.pseudommus are 31.7%,33.3%,35.0%and 39.2% respectively.The mean expected heterozygosities of the four populations are 0.116,0.125,0.126,and 0.144,respectively.Low genetic distances(ranging from 0.0118 to 0.0309)and Fst estimates(0.020 to 0.024) among the populations indicated that there is no significant differentiation between T.rubripes and T.pseudommus and suggested that only one species is involved. 相似文献
8.
9.
详细记叙了暗纹东方Tun胚胎发育各阶段的形态特征及早期发育的生物学资料,暗纹东方Tun的卵为沉性卵,入水后具粘性,其粘度与受精效果有关。卵径为1.118-1.274mm,具油球280-390个,油球径为0.026-0.078mm。作者采用连续法对受精卵的发育进行观察。 相似文献
10.
本文对印度恒河豚、日本海江豚、东海江豚、真海豚和南方宽吻海豚的小肾和肾小球进行了测量和计数,并对小肾结构指数做了测定。结果表明,江豚、真海豚和南方宽吻海豚的相对肾重和小肾数明显大于恒河豚;真海豚和宽吻海豚的肾小球总数远大于江豚和恒河豚,恒河豚最少。但总的肾小球表面积、每克体重的肾小球表面积均低于相当体重的陆生哺乳动物。鲸类肾脏的小肾化虽然增加了肾小球的数量,但并没有增加肾的滤过面积。几种齿鲸的小肾结构指故无一定规律.也没有发现它与环境盐度的对应关系。因此,对于鲸类肾脏如何适应它们旺盛的生理代谢和小肾结构指数与肾浓缩能力的关系还需进一步研究。 相似文献