海湾扇贝养殖群体遗传多样性的研究

用等位基因酶的聚丙烯酰胺凝胶电泳技术,研究了大连沿岸不同生态环境条件下的大李家湾低排筏、大李家湾高排筏、凌水桥、棋盘磨4个海湾扇贝养殖群体的遗传多样性.在4个群体的7种等位基因酶和闭壳肌蛋白中均检测到了22个基因位点,各群体的多态位点比例分别为22.73%,22.73%,22.73%,18.18%(P≤0.95)和27.27%,27.27%,31.82%,36.36%(P≤0.99);杂合度观测值分别为0.064,0.071,0.075,0.069;Hardy-Weinberg平衡偏离指数分别为-0.068,-0.020,-0.032,-0.050;近交系数分别为0.568,0.565,0.487,0.550;位点等位基因有效数分别为1.102,1.109,1.143,1.122;遗传变异综合评价指数分别为0.0060,0.0071,0.0088,0.0073.海湾扇贝养殖群体遗传多样性总体水平较低,但在这4个群体中,凌水桥群体的遗传多样性水平最高,大李家湾高排筏和棋盘磨群体的遗传多样性水平较高,大李家湾低排筏群体遗传多样性水平最低.     

海桑属红树植物遗传多样性和引种关系研究

以海南东寨港红树林自然保护区内无瓣海桑(Sonneratia apetala)、海南海桑(S.hainanensis)、拟海桑(S.paracaseolaris)、杯萼海桑(S.abla)、大叶海桑(S.ovata)、海桑(S.caseolaris)等6种海桑属红树植物为材料,对15个有效引物进行RAPD分析,共扩增出512条带,其中多态性条带为297,占总扩增条带的58.01%.Nei指数法分析和UPGMA统计分析表明,6种海桑属红树植物分为A,B,C3个组,平均遗传距离为0.38.A组包括无瓣海桑、海南海桑、大叶海桑、怀萼海桑,其中无瓣海桑、海南海桑、大叶海桑处于同一个亚组.B组包括拟海桑.C组包括海桑.对海南和福建无瓣海桑种群进行RAPD分析.对Shannon表型多样性指数统计结果表明,福建种群为0.669,海南种群为0.671,各种群遗传变异较大,这与无瓣海桑种群广泛的适应性相一致.对种群间的Shannon表型多样性指数分析表明,种群内的遗传变异占整个遗传变异的93.3%,而种群间的遗传变异仅占6.7%.这表明无瓣海桑种群的大部分遗传变异存在于种群内,而种群间的遗传变异较小.由此可见,无瓣海桑基因组丰富的多样性,是使其由海南成功引种到福建的重要因素.     

翘嘴红鲌(Erythroculter ilishaeformis Bleeker)种群遗传多样性的RAPD分析

采用RAPD技术对翘嘴红鲌养殖群体进行了DNA多态性检测.共采用40个随机引物进行扩增,其中14个引物可获得清晰且重复性好的扩增图谱,共扩增出121个RAPD位点,具有多态现象的位点为40个,多态位点比例为33.06%.翘嘴红鲌群体的遗传相似系数为 0.8878-0.9600,平均为0.9201,遗传变异度为0.0799.Shannon多样性指数为10.8824,Shannon多样性值为0.0899.研究表明,翘嘴红鲌目前的种质资源状况令人堪忧,改变目前人工繁育模式,建立原种、良种场,丰富物种遗传多样性是资源保护的基础.     

Study on genetic diversity of cultivated populations in 4 species of shrimps

Genetic diversity of cultivated populations was investigated using assay of vertical slabpolyacrylamide gel electrophoresis in 4 species of shrimps, which were Penaeus japonicus, Penaeus monodon , Penaeus vannamei and Metapenaeus ensis, The results showed that the mean number of alle-les per locus (A) is 1.3±0.2, 1.3±0.1, 1.3±0.1 and 1.3 ±0.1 respectively; the percentage of polymorphic loci (P0.95) is 12.5, 6.7, 20 and 23.5 respectively; the expected heterozygosity (He) is 0.042±0.034,0.042±0.031, 0.094±0.042 and 0.097±0.047 respectively; and the observed heterozygosity (H0)is 0.029±0.024, 0.028±0.023,0.154±0.082 and 0.150±0.084 respectively. The difference of genetic diversity is obvious in 4 species of shrimps. The degree of genetic diversity is M. ensis > P. vannamei > P. japonicus > P. monodon. In short, the lower level of genetic diversity is estimated in 4 species of shrimps.     

Population structure of Haliotis rubra from South Australia inferred from nuclear and mtDNA analyses

1Introduction ThemajorityofAustralia’sabalonefisheryex ports(5.135kt,worth＄216millionin2002～2003,ABARE2004)consistofblacklipabalone(HaliotisrubraLeach,1814).AssuchH.rubrais consideredasanimportantmarineresourcewithin Australia.Likemanyabalonespecieswor…     

鲫鱼(Carassius auratus)在微冻保鲜过程中的质量变化

该文研究鲫鱼 ( Carassius auratus)在微冻 ( - 3℃ )保鲜过程中的质量变化规律。以感官评价、细菌总数、T- VBN值、p H值、ATPase活性、K值等作为质量指标。实验结果表明 ,微冻可以明显抑制细菌总数的增长 ,维持较低的 T- VBN和 K值。但是 ,微冻条件下鲫鱼的 ATPase活性下降速度较快     

Rare species, habitat diversity and functional redundancy in marine benthos

Macro-ecological theories relating species richness, abundance, range size, biological traits and environmental tolerance have rarely been tested in marine soft-sediments, despite the spatial extent of these habitats and the inherent richness of resident communities. This study examines the contribution of rare species to marine soft-sediment communities from New Zealand, focussing on the relationships of range size with abundance, environment, habitat diversity and life history traits. 54% of the 351 species sampled exhibited restricted ranges (found at ≤ 2 sites). In contrast to many terrestrial systems, we observed only a weak positive relationship between abundance and frequency of occurrence. Restricted-range species were not randomly distributed, with their distribution related to habitat characteristics, suggesting an important link between habitat diversity and rarity. They exhibited a similar range of traits to the total observed species pool, suggesting that they are not only important to biodiversity but could play a role in stability. Restricted range species were generally not small and this, together with the number of different biological traits represented, suggests that rare species are important to the functioning of marine systems. Thus, our results highlight the importance of considering rare species in habitat-based approaches to conservation.     

A Functional Analysis of the Benthic Macrofauna of the São Sebastião Channel (Southeastern Brazil)

Abstract.  The major problem in coastal areas of developing countries is disturbance caused by anthropogenic influence. This disturbance can be quantified by analysing the distribution and composition of marine communities using uni- and multivariate techniques and the biotic index. A study of benthic macrofauna was carried out along the São Sebastião Channel, northern coast of São Paulo State, Brazil, in an area with a submarine outfall, a petroleum terminal and a commercial harbour. Sampling was undertaken seasonally, by means of a van Veen grab (0.1 m²) at 15 oceanographic stations, from November 1993 to August 1994. A total of 392 species were identified (129 Polychaeta, 127 Mollusca, 98 Crustacea, 28 Echinodermata and 10 other phyla). The sedimentary pattern recorded for the São Sebastião Channel is very heterogeneous, influenced mainly by strong wind-driven currents, and differs from nearby shelf areas. The study area could be divided into three regions based on sediment texture and fauna: one region dominated by medium and coarse sand with low values of organic carbon; a second area where pelitic fractions were dominant with high values of organic carbon and nitrogen; and a third region characterised by fine and very fine sand, presenting intermediate organic carbon values. No temporal significant variation in abundance and species composition was found, except in autumn. The use of the 'marine Biotic Coefficient' showed the same ecological trend as the faunal abundance and demonstrated that the central continental region of the channel is affected by human activities.