Inheritance Pattern of Microsatellite Loci and Their Use for Kinship Analysis in the Japanese Scallop Patinopecten yessoensis

The inheritance mode of seven microsatellite markers was investigated in Patinopecten yessoensis larvae from four con-trolled crosses,and the feasibility of using these markers for kinship estimation was also examined. All the seven microsatellite loci were compatible with Mendelian inheritance. Neither sex-linked barriers to transmission nor major barriers to fertilization between gametes from the parents were evident. Two of the seven loci showed the presence of null alleles in two families,suggesting the need to conduct comprehensive species-specific inheritance studies for microsatellite loci used in population genetic studies. However,even if the null allele heterozygotes were considered as homozygotes in the calculation of genetic distance,offspring from four families were all unambiguously discriminated in the neighbor-joining dendrogram. This result indicates that the microsatellite markers used may be capable of discriminating between related and unrelated scallop larvae in the absence of pedigree information,and of investigating the effective number of parents contributing to the hatchery population of the Japanese scallop.

Microsatellite-Centromere Mapping in Japanese Scallop(Patinopecten yessoensis) Through Half-Tetrad Analysis in Gynogenetic Diploid Families

Gene-centromere mapping is an essential prerequisite for understanding the composition and structure of genomes. Half-tetrad analysis is a powerful tool for mapping genes and understanding chromosomal behavior during meiosis. The Japanese scallop(Patinopecten yessoensis), a cold-tolerant species inhabiting the northwestern Pacific coast, is a commercially important marine bivalve in Asian countries. In this study, inheritance of 32 informative microsatellite loci was examined in 70-h D-shaped larvae of three induced meiogynogenetic diploid families of P. yessoensis for centromere mapping using half-tetrad analysis. The ratio of gynogenetic diploids was proven to be 100%, 100% and 96% in the three families, respectively. Inheritance analysis in the control crosses showed that 51 of the 53 genotypic ratios observed were in accordance with Mendelian expectations at the 5% level after Bonferroni correction. Seven of the 32 microsatellite loci showed the existence of null alleles in control crosses. The second division segregation frequency(y) of the microsatellite loci ranged from 0.07 to 0.85 with a mean of 0.38, suggesting the existence of positive interference after a single chiasma formation in some chromosomes in the scallop. Microsatellite-centromere distances ranged from 4 c M to 42 c M under the assumption of complete interference. Information on the positions of centromeres in relation to the microsatellite loci will represent a contribution towards the assembly of genetic maps in the commercially important scallop species.

Spatial diff erence in net growth rate of Yesso scallop Patinopecten yessoensis revealed by an aquaculture ecosystem model

Identifying the main factors on spatial diff erences in net growth rate of Yesso scallop(Patinopecten yessoensis)in culture system is the key to eff ective aquaculture management and development.Coupling a 3D ecosystem model(ROMS-CoSiNE)with a dynamic energy budget model for scallops,a Yesso scallop culture ecosystem(YeSCE)model was established with which scallop growth was simulated with real seeding density and juvenile size from local aquaculture experiments from December 1,2012 to November 30,2013.Results show that the YeSCE model has reasonably simulated the environmental variation and scallop net growth rate in the Changhai sea area.The growth of scallops was slow in winter and midsummer and was limited mainly by temperature.Food availability was a key factor that contributed to the fast growth of the scallops during spring to early summer and in autumn.Generally,the scallops cultured in the north part of the Changhai sea area grew faster than those in the south;and the net growth rate for scallops cultured near the island was signifi cantly higher compare to the others,which is probably correlated to the spatial distribution of food availability.Based on the correlation analysis,the spatial diff erences of the net growth rate were largely aff ected by the length of the match timing of temperatures and food availability.The results of this study provide a scientifi c support for optimizing bottom culture planning and adjusting bottom culture methods.

Nutrient effects of broodstocks on the larvae in Patinopecten yessoensis

Patinopecten yessoensis is a commercial valuable species. This study deals with the effect of nutrient effects of the broodstock(mainly ovaries) on the larvae. Concentrations of total carbohydrate, total protein and total lipid in the gonads of P. yessoensis from three Hatcheries(Hatchery 1, Hatchery 2, and Hatchery 3) were determined before and after spawning. The relationship between the nutrient concentration in ovaries before spawning(BC) and that of larvae(LC) was assessed as well as the change in nutrient levels in ovaries after spawning(DC). Results indicate that the BC of total carbohydrate(7.66%) and total lipid(14.48%) in ovaries were significantly higher than in testes(5.20%, 5.20% respectively), whereas the BC of total protein in the ovaries was lower(61.76%) than in the testes(81.67%). The different gonadal composition suggests the different nutrient demands between male and female broodstocks in breeding season. P atinopecten yessoensis gonads contained a higher proportion of lipids, in comparison to other bivalves, which might be a response to the low ambient water temperatures. Further analysis of fatty acids showed that the concentrations of n-3PUFA, EPA and DHA in larvae(LC) were positively correlated with BC and DC, indicating the significant nutrient influence of broodstocks on the larvae. As these fatty acids are important in metabolism, and have been demonstrated to be influential to the viability of the larvae, larval growth and the settlement, spat growth, and juvenile survival in many bivalves, they could possibly be used as indexes to evaluate, and predict condition of broodstocks and larvae.

影响筏养虾夷扇贝生长的因素分析

虾夷扇贝(Patinopecten yessoensis)筏式养殖近年来受到诸多因素影响,暴露出新问题,本文根据调查研究结合国内外学者的研究成果从苗种质量、养殖密度、竞争性生物等方面探讨影响筏养虾夷扇贝生长因素。

虾夷扇贝养殖群体及其子代的遗传多样性分析

虾夷扇贝(Patinopecten(Mizuhopecten)yessoensis)于1982年从日本引进,在中国已经成为一个很重要的产业。本研究利用微卫星标记,对獐子岛海域2个养殖群体虾夷扇贝(大耗岛、褡裢岛),1个日本野生群体遗传多样性进行了评估,并对2个养殖群体的群体内繁育和群体间杂交后代进行了遗传和生长检测。结果表明:养殖群体与日本野生群体相比,其遗传多样性没有显著降低,养殖群体遗传多样性较高,养殖状况暂时良好。TL群体和DH群体遗传距离很近,DH、TL群体和RB群体的遗传距离远大于TL群体和DH群体间的遗传距离。说明2个养殖虾夷扇贝群体遗传分化较小。分别对4个子代群体的壳长、壳高在幼苗培育第1、5、10、15、20、100、190天进行测量,结果表明生长性状差异不显著。4个子代群体的遗传多样性差异也不显著,说明养殖群体的遗传背景不清楚,种质资源混交较严重。本研究结果反映了我国虾夷扇贝种质资源评估状况,并为虾夷扇贝的健康养殖提供基础数据。

不同生长时期虾夷扇贝壳质的超微结构观察及表面5种元素组成分析

以人工吊养的已明确月龄的(5月龄、7月龄、9月龄、12月龄、18月龄、30月龄)虾夷扇贝(Patinopecten(Mizuhopecten)yessoensis)为实验材料,从壳顶沿生长线方向纵切,用扫描电镜观察了不同生长时期贝壳的壳质结构,并探讨了虾夷扇贝生长发育过程中壳质结构的一般性变化规律。结果表明,虾夷扇贝壳质包括均质型(homogeneous)、叶状型(foliated)、交错片状型(crossed lamellar)、棱柱型(prismatic)4种结构类型。随着生长期的增加,壳质结构逐渐趋向于复杂,叶状结构和交错片状结构的比例增加。同时分析比较了同一时期"象牙白"品系和普通红褐色虾夷扇贝的贝壳外表面5种化学元素的含量,"象牙白"品系和普通红褐色贝壳所含的C、O、Na、Mg、Ca 5种元素质量分数分别为:24.26%、60.44%、0.63%、0.48%、14.18%和18.24%、56.48%、0.52%、0.36%、24.41%。

Cytogenetic analysis in two scallops (Bivalvia:Pectinidae) by PRINS and PI banding

Cytogenetic analysis was performed for the bay scallop （Argopecten irradians Lamarck 1819） and the Japanese scallop （Patinopecten yessoensis Jay 1857 ） by primed in situ labeling （PRINS） and propidium iodide （PI） banding techniques. The PRINS analysis revealed that major rRNA genes were clustered in two loci on the telomeric regions of the short arms on two acrocentric chromosome pairs in A. irradians and on two submetacentric pairs in P. yessoensis. The histone H3 gene sites differed in number and location between these two species. The C-band-like patterns revealed by PI staining varied considerably between these two species. A. irradians displayed terminal bands at long arms on all chromosomes, centromeric bands on some pairs and interstitial bands on five pairs. P. yessoensis exhibited only centromeric bands on all chromosomes. These results would contribute to the better understanding of karyotype evolution in A. irradians and P. yessoensis.

超声清洗对活品虾夷扇贝品质的影响

通过3个时间(0、5、10 min)的超声清洗试验,分析虾夷扇贝(Patinopecten yessoensis)的水质指标以及品质指标的变化规律,确定虾夷扇贝的最佳清洗时间,并模拟3组扇贝气调包装(80%O_(2)、20%N_(2))下的流通运输,分析不同清洗时间对活品虾夷扇贝的流通品质影响。结果表明,在超声清洗过程中3组虾夷扇贝的存活率都是100%,且均对质构和糖原无显著影响,其中超声清洗10 min的除杂率最高,为4.02%,菌落总数最少,为1.1×10^(5)CFU/mL,清洗后水质变差。不同清洗时间下,模拟运输过程中的虾夷扇贝菌落数均随着清洗时间的延长呈上升趋势,超声清洗10 min虾夷扇贝体内的菌落数随着运输时间的延长上升速率较为缓慢。超声清洗10 min为较理想的清洗时间,虾夷扇贝品质保持较好。

A Way to Decrease the Negative Impact of Aquaculture on other Marine Inhabitants

Spat collectors deployed at sea, in addition to the target species, attract also many larvae of accompanying species, which die after transplanting the cultivated one into cages. However, these juveniles often have a higher value than the cultivated species, and their mortality is caused by smaller sizes. These are： red king crab, Japanese sea cucumber, sea urchins, Japanese cucumaria and several species of ascidians and sponges. However, the use of a realized niche, rather than a fundamental one, in selecting the area and depth to install collectors, and also improvement of their design, make it possible to cultivate a target species without reseeding to other constructions. This not only facilitates the cultivation process, but also increases the survival rate of the cultivated and accompanying species, since at the bottom, they reach either marketable or viable size in comfortable conditions.