A NOVEL SHELL COLOR VARIANT OF THE PACIFIC ABALONE HALIOTIS DISCUS HANNAI INO SUBJECT TO GENETIC CONTROL AND DIETARY INFLUENCE

Molluscan shells may display a variety of colors, which formation, inheritance, and evolutionary significance are not Well understood. Here we report a new variant of the Pacific abalone Haliotis discus hannai that displays a novel orange shell coloration (O-type) that is clearly distinguishable from the Wild green-shelled abalone (G-type). Controlled mating experiments between O- and G-type abalones demonstrated apparent Mendelian segregations (1:1 or 3:1) in shell colors in F-2 families, which support the notion that the O- and G-types are under strict genetic control at a single locus With a recessive o (for orange shell) allele and a dominant G (for green shell) allele. Feeding with different diets caused modifications of shell color within each genotype, ranging from orange to yellow for O-type and green to dark-brown for the G-type, without affecting the distinction between genotypes. A previously described bluish-purple (B-type) shell color was found in one of the putative oo X oG crosses, suggesting that the B-type may be it recessive allele belonging to the same locus. The new O-type variant had no effect on the growth of Pacific abalone on the early seed-stage. This Study demonstrates that shell color in Pacific abalone is subject to genetic control as well as dietary modification, and the latter probably offers selective advantages in camouflage and predator avoidance.

Heat-shock protein70 gene expression in four hatchery Pacific Abalone Haliotis discus hannai Ino populations using for marker-assisted selection

Heat shock proteins (Hsps) are molecular chaperones that help organisms cope with stressful conditions. Here, we report on the growth rates and Hsp70 expressions in inbred and hybrid populations of abalone Haliotis discus hannai Ino. In abalone, inbred populations expressed more Hsp70 than hybrid populations at all temperatures, except at very high temperatures close to the physiological limit. At benign temperatures, there was a clear trend towards higher Hsp70 expression in inbred than hybrid populations, whereas at higher temperatures, a trend in the opposite direction was observed. The temperature of maximal Hsp70 expression (T-peak) varied with the population type. The T-peak of inbred populations (26 degrees C) was lower than that of the hybrid populations (28 degrees C). The maximal inducible Hsp70 of inbred populations was higher than that of hybrid populations. The results showed a trend towards higher expression in inbred population at a lower temperature. These results provide direct experimental evidence that hybrids can cope with the intrinsic stress even at non-stressful temperatures. The constitutive Hsp70 may therefore be used for marker-assisted selection in a breeding programme.

Identification of quantitative trait loci for growth-related traits in the Pacific abalone Haliotis discus hannai Ino

The locations and effects of quantitative trait loci (QTL) were estimated for nine characters for growth-related traits in the Pacific abalone (Haliotis discus hannai Ino) using a randomly amplified polymorphic DNA (RAPD), amplification fragment length polymorphism (AFLP) and SSR genetic linkage map. Twenty-eight putatively significant QTLs (LOD > 2.4) were detected for nine traits (shell length, shell width, total weight, shell weight, weight of soft part, muscle weight, gonad and digestive gland weight, mantle weight and gill weight). The percentage of phenotypic variation explained by a single QTL ranged from 8.0% to 35.9%. The significant correlations (P < 0.001) were found among all the growth-related traits, and Pearson's correlation coefficients were more than 0.81. For the female map, the QTL for growth were concentrated on groups 1 and 4 linkage maps. On the male map, the QTL that influenced growth-related traits gathered on the groups 1 and 9 linkage maps. Genetic linkage map construction and QTL analysis for growth-related traits are the basis for the marker-assisted selection and will eventually improve production and quality of the Pacific abalone.

Effects of the initial size, stocking density and sorting on the growth of juvenile Pacific abalone, Haliotis discus hannai Ino

During winter months, a novel overwintering mode of transferring juvenile abalones to open seawaters in southern China rather than keeping them in closed land-based nursery systems in northern China is a popular practice. The initial size, stocking density and sorting are among the first considerations when establishing an abalone culture system. This study aimed to investigate the effects of these factors on the growth of juvenile Pacific abalone, Haliotis discus hannai Ino, during overwintering. Juvenile abalones were reared in multi-tier basket form for overwintering in open seawaters in southern China for 106 days. The daily growth rates (DGRs) in the shell length of all experimental groups ranged from 67.08 to 135.75 mu m day(-1), while the specific growth rates (SGRs) were 0.2447-0.3259% day(-1). Variance analysis indicated that both DGRs and SGRs in shell length were significantly affected by the initial body size and stocking density. Furthermore, the effects of stocking density on DGRs and SGRs varied with the initial size. However, sorting abalones according to their initial sizes may not be necessary in practice as sorting did not alter growth significantly at all densities in this study. Factors potentially affecting abalone growth such as genetic control and intraspecific competition were discussed.

Experimental evaluation of heterobeltiosis and heterosis between two populations of Pacific abalone Haliotis discus hannai Ino

A2 x 2 factorial cross between two populations of Pacific abalone Haliotis discus hannai Ino, collected separately from Dalian (D) in China and Miyagi (M) in Japan, was conducted to compare performances in fertilization rate, hatching rate, metamorphosis rate and growth at days 20, 43, 160 and 330 between purebreds (DD and MM) and crossbreds (DM and MD) and investigate the magnitude of heterobeltiosis (better parent) and heterosis (mid-parent). Heterobeltiosis and heterosis for all the traits analyzed were evidently different between crossbreds DM and MD. Heterobeltiosis in the crossbred DM varied among traits, with values of 2.5% for the fertilization rate, 2.2% for the hatching rate, -1.9% for the metamorphosis rate and 7.4% for the growth at the (lay 330. The crossbred DM displayed positive heterotic values for fertilization rate (5.4%), hatching rate (7.4%), metamorphosis rate (7.6%) and growth (12.0%) at the day 330. However, both heterobeltiosis and heterosis for all the traits in the crossbred MD were negative except those for the growth at days 20 and 43. The results indicate the importance of selecting superior hybrid varieties if the exploitation of hybrid vigor is considered in the Pacific abalone breeding program.

Genetic parameter estimates for growth traits at early stage of Pacific abalone, Haliotis discus hannai Ino

Heritability and genetic and phenotypic correlations were estimated for juvenile growth traits of Pacific abalone Haliotis discus hannai Ino. The estimates were calculated from shell length and shell width measurements on progeny resulting from 12 half-sib families and 36 full-sib families obtained using artificial fertilization of mating three females to each male. The measurements were taken at 10, 20 and 30 d after fertilization. It was found that heritability estimates based on sire component ranged from 0.23 to 0.36 for shell length and 0.21 to 0.32 for shell width. Heritability estimates from dam component were larger than those from sire component at three ages, indicating presence of maternal effects, non-additive genetic effects and common environmental effects. Phenotypic correlations were significant at three ages (P < 0.05), with values of 0.92, 0.93 and 0.92, respectively. Genetic correlations from the paternal half-sib correlation analysis were highly positive at three ages, with values of 0.50, 0.78 and 0.81, respectively. The results suggest that selective breeding is an effective approach to improving growth traits of Pacific abalone stocks.

A preliminary genetic linkage map of the pacific abalone Haliotis discus hannai Ino

Preliminary genetic linkage maps were constructed for the Pacific abalone (Haliotis discus hannai Ino) using amplified fragment length polymorphism (AFLP), randomly amplified polymorphic DNA (RAPD), and microsatellite markers segregating in a F, family. Nine microsatellite loci, 41 RAPD, and 2688 AFLP markers were genotyped in the parents and 86 progeny of the mapping family. Among the 2738 markers, 384 (including 365 AFLP markers, 10 RAPD markers, and 9 microsatellite loci) were polymorphic and segregated in one or both parents: 241 in the female and 146 in the male. The majority of these markers, 232 in the female and 134 in the male, segregated according to the expected 1:1 Mendelian ratio (alpha = 0.05). Two genetic linkage maps were constructed using markers segregating in the female or the male parent. The female framework map consisted of 119 markers in 22 linkage groups, covering 1773.6 cM with an average intermarker space of 18.3 cM. The male framework map contained 94 markers in 19 linkage groups, spanning 1365.9 cM with an average intermarker space of 18.2 cM. The sex determination locus was mapped to the male map but not to the female map, suggesting a XY-male determination mechanism. Distorted markers showing excess of homozygotes were mapped in clusters, probably because of their linkage to a gene that is incompatible between two parental populations.

Characterization of 12 single nucleotide polymorphisms (SNPs) in Pacific abalone, Haliotis discus hannai

We report here for the first time 12 polymorphic single nucleotide polymorphisms (SNPs) in a commercially important gastropod, Pacific abalone (Haliotis discus hannai) that were identified by searching expressed sequence tag database. These SNP loci (seven nuclear and five mitochondrial SNPs) were polymorphic among 37 wild abalone individuals, based on a four-primer allele-specific polymerase chain reaction analysis. All loci had two alleles and the minor allele frequency ranged from 0.027 to 0.473. For the seven nuclear SNPs, the expected and observed heterozygosities ranged from 0.053 to 0.499 and from 0.054 to 0.811, respectively.

Mining expressed sequences for single nucleotide polymorphisms in Pacific abalone Haliotis discus hannai

Although single nucleotide polymorphisms (SNPs) are important resources for population genetics, pedigree analysis and genomic mapping, such loci have not been reported in Pacific abalone so far. In this study, a bioinformatics strategy was adopted to discover SNPs within the expressed sequences (ESTs) of Pacific abalone, Haliotis discus hannai, and furthermore, polymerase chain reaction direct sequencing (PCR-DS) and allele-specific PCR (AS-PCR) were used for SNPs detection and genotype scoring respectively. A total of 5893 ESTs were assembled and 302 putative SNPs were identified. The average density of SNPs in ESTs was 1%. Fifty-two sets of sequencing primers were designed from SNPs flanking ESTs to amplify the genomic DNA, and 13 could generate products of expected size. Polymerase chain reaction direct sequencing of the amplification products from pooled DNA samples revealed 40 polymorphic SNP loci. Using a modified tetra-primer AS-PCR, seven mitochondrial and six nuclear SNPs were typed and characterized among 37 wild abalones. In conclusion, it is feasible to discover SNPs from number limited ESTs and the AS-PCR as a simple, robust and reliable assay could be a primary method for small- and medium-scale SNPs detection in abalones as well as other non-model organisms.

Cloning and expression analysis of a HSP70 gene from Pacific abalone (Haliotis discus hannai)

Heat shock protein 70 (HSP70), the primary member of HSPs that are responsive of thermal stress, is found in all multicellular organisms and functions mostly as molecular chaperon. The inducible HSP70 cDNA cloned from Pacific abalone (Haliotis discus hannai) using rapid amplification of cDNA ends (RACE), was highly homologous to other HSP70 genes. The full-length cDNA of the Pacific abalone HSP70 was 2631 bp, consisting of a 5'-terminal untranslated region (UTR) of 90 bp, a 3'-terminal UTR of 573 by with a canonical polyadenylation signal sequence AATAAA and a poly (A) tail, and an open reading frame of 1968 bp. The HSP70 cDNA encoded a polypeptide of 655 amino acids with an ATPase domain of 382 amino acids, the substrate peptide binding domain of 161 amino acids and a C-terminus domain of 112 amino acids. The temporal expression of HSP70 was measured by semi-quantitative RT-PCR after heat shock and bacterial challenge. Challenge of Pacific abalone with heat shock or the pathogenic bacteria Vibrio anguillarum resulted in a dramatic increase in the expression of HSP70 mRNA level in muscle, followed by a recovery to normal level after 96 h. Unlike the muscle, the levels of HSP70 expression in gills reached the top at 12 h and maintained a relatively high level compared with the control after thermal and bacterial challenge. The upregulated mRNA expression of HSP70 in the abalone following heat shock and infection response indicates that the HSP70 gene is inducible and involved in immune response. (c) 2006 Elsevier Ltd. All rights reserved.

皱纹盘鲍的遗传育种与养殖技术研究

优良的种质是产业发展的重要保证，品种更新和养殖技术的发展已经给世界农业带来了令人瞩目的成就，然而我国水产生物的育种工作刚处于起步阶段，而育种技术的研究则更是滞后。借鉴陆生生物中发展起来的相对成熟的研究方法，可以帮助加快海洋生物遗传育种相关研究的进度。本研究以我国北方海区重要的海洋经济动物－皱纹盘鲍为研究对象，从表型遗传、数量性状遗传等2个方面开展了皱纹盘鲍的遗传育种研究，同时从幼鲍培育密度与分选效应等方面研究了皱纹盘鲍的中间培育技术。 主要结果如下： 1. 皱纹盘鲍的贝壳颜色遗传、食物对贝壳颜色表现型的影响，贝壳颜色与生长速度间的关系 将贝壳颜色为橘红色（O表型）的突变型皱纹盘鲍与贝壳颜色为绿色（G表型）的野生型皱纹盘鲍进行了连续2代的交配实验。结果表明：皱纹盘鲍橘红色的贝壳颜色相对于绿色的贝壳颜色为隐性性状，皱纹盘鲍的贝壳颜色表型受单位点、2个等位基因遗传控制，其中基因型为oo的个体，贝壳颜色的表现型为橘红色（O表型），而基因型为GG或Go的个体，贝壳颜色的表现型为野生型（G表型）。 为探讨食物类型对不同基因型皱纹盘鲍贝壳颜色表现型的影响，对不同贝壳颜色表型的个体投喂不同种类的食物，结果表明，除遗传因素外，皱纹盘鲍的贝壳颜色表现型显著地受食物类型的调控。其中oo基因型的个体，在摄食底栖硅藻（Navicula sp.）和红藻时，贝壳颜色的表型为橘红色；而在摄食褐藻、绿藻和以海带粉为唯一海藻源的人工配合饵料时，贝壳颜色的表型为黄色。GG和Go基因型的个体，在摄食底栖硅藻、红藻时，贝壳颜色的表型为褐红色；在摄食褐藻、绿藻和以海带粉为唯一海藻源的人工配合饵料时，贝壳颜色的表型为绿色。该结果表明，相同基因型的皱纹盘鲍在摄食不同类型的食物时，贝壳表现型不同，即不同类型的食物可以导致2种基因型皱纹盘鲍的贝壳颜色表现型在一定范围内发生转换：oo基因型的个体，贝壳的颜色可以表现为橘红色或者黄色，不会出现野生型皱纹盘鲍的褐红色或绿色；而GG与Go基因型的个体，相应的贝壳颜色表型只能是褐红色或者绿色，不会出现oo基因型可能表现的橘红色或黄色。特定基因型的皱纹盘鲍，在摄食特定类型的食物时贝壳的相应部位可表现出特定的颜色。皱纹盘鲍的这种“食物－贝壳颜色”的相关性可作为一种形态标记，用于标识皱纹盘鲍的个体和群体，该标记技术可用于皱纹盘鲍的养殖技术和遗传学研究。 此外，选用了贝壳颜色遗传学实验中建立的贝壳颜色发生分离的家系为实验材料，以壳长为指标，分析比较了来自相同家系的O表型与G表型个体之间的生长速度。结果表明，在幼鲍发育至412天止的3-5个统计时段内，没有在同一家系来源的2种贝壳颜色表型个体之间检验到生长速度的显著差异。 2. 皱纹盘鲍不同选育群体及杂交群体的贝壳形态参数分析 在皱纹盘鲍的7个群体中（包括已经对生长速度为指标进行了多代人工选育的群体4个、野生群体之间直接杂交繁育的杂交F1群体3个），测量了4-6龄成体样本的壳长（L）、壳宽（W）、壳高（H）和壳重（Sw），并计算了L/（L+W+H）、W/（L+W+H）、H/（L+W+H）和Sw/（L×W×H）等4个壳形态学参数。用方差分析方法（MANOVA、ANOVA）统计并比较了这些壳形态参数在皱纹盘鲍群体间的遗传变异。结果表明，4个壳形态参数在不同群体间变异系数分别为0.34、0.74、2.62和6.54，其中，H/（L+W+H）与Sw/（L×W×H）在各供试群体间均具有较高的多态性且差异达显著水平，表明这2个参数在不同群体间存在较高的遗传变异。由于在活体情况下无法测量壳重（Sw）性状，建议以参数H/（L+W+H）为指标对皱纹盘鲍贝壳形态（如壳型）等进行人工选择。 3. 皱纹盘鲍成体阶段生长性状的遗传参数估计 采用巢式设计，分析了成体阶段不同发育期皱纹盘鲍的壳长与生长速率的遗传力、不同发育期的壳长性状之间的遗传相关、以及不同发育期的生长速率之间的遗传相关，结果表明：（1）壳长遗传力在受精后第70 、130、320、320、380、490与550天的雄性组分估计值分别为0.161 ± 0.075、0.312 ± 0.131、0.326 ± 0.331、0.135 ± 0.228、0.153 ± 0.185和0.180 ± 0.106；雌亲组分估计分别为0.312 ± 0.172、0.699 ± 0.168、0.695 ± 0.168、0.977 ± 0.407、0.427 ± 0.195和0.449 ± 0.027。（2）生长速率遗传力在受精后第320~380天、490 ~ 550天，雄、雌组分估计值分别为0.080 ± 0.120（雄）、 0.210 ± 0.191（雌）以及0.299 ± 0.146（雄）、0.306± 0.148（雌）。雌亲组分的壳长遗传力和生长速率遗传力估计值较大且均达显著水平，表明皱纹盘鲍在成体阶段依然受母性效应的影响。成体阶段生长性状遗传力水平的估计对制定科学的皱纹盘鲍育种方案有指导意义。（3）雄亲组分估计的不同发育期（第390 ~ 550天）壳长间遗传相关为0.597 ~ 1.000，雌亲组分估计为0.589 ~ 1.177。由雄亲、雌亲组分估计，受精后第320~380天与第490 ~ 550天两个发育阶段生长速率间遗传相关均接近于0。雌亲组分估计不同发育期壳长间遗传相关均达显著水平（t0.05, d.f.=13 = 4.33 ~ 11.69，P<0.01），表明壳长性状早期选择有效，即在皱纹盘鲍早期阶段依据壳长性状对个体进行择优或去劣可在后期阶段获得壳长较大的个体。由于使用的雄亲数目少（8个父系半同胞），实验中以雄亲组分估计的遗传参数误差较大。 4. 皱纹盘鲍选育系间的群体杂交 进行了皱纹盘鲍4个人工选育系之间的完全双列杂交实验，以群体交配的方式共建立了16个组合；此外，以大连“98”选群与汕头“S”选群为亲本，以群体交配的方式建立了4个交配组合。对不同方向的杂交组合进行了中亲杂种优势、超亲杂种优势以及配合力等方面的评价。 （1）测量了4个选育群体（R、97、S和J）及其各杂交组合在受精后第9、20和30天时的壳长，统计分析了不同选育系间壳长性状的差异、评价了不同方向杂交组合的中亲与超亲杂种优势、以及配合力。结果如下： 选育系群体内交配繁育的4个组合，在受精后第9、20和30天的壳长均有显著差异，其中，97  97组合在早期发育各阶段均为最小，分别为0.462 ± 0.023mm、0.698 ± 0.057mm和1.476 ± 0.234mm；S  S组合的3次测量值均为最大，分别为0.522 ± 0.023mm、0.824 ± 0.084mm和1.798 ± 0.229mm。 两个方向杂交组合与选育系亲本群体内交配组合的平均值和高亲值比较，得到如下结果：（A）受精后第9天壳长表现正向中亲杂种优势的组合有6个、表现负向中亲杂种优势的组合6个，其中J  97组合的中亲优势率最高，为9.05%；R  S组合最低，为-6.61%。正向高亲杂种优势组合有4个、负向高亲杂种优势组合有8个，其中S  J组合的高亲优势率最高，为5.77%；R  S组合最低，为-7.96%。（B）受精后第20天壳长表现正向中亲杂种优势的组合有7个、表现负向中亲杂种优势的组合5个，其中J  97组合的中亲优势率最高，为12.60%；J  R组合最低，为-8.72%。正向高亲杂种优势组合有3个、负向高亲杂种优势组合有11个，其中J  97组合的高亲优势率最高，为12.20%；J  R组合最低，为-12.67%。（C）受精后第30天壳长表现正向中亲杂种优势的组合有7个、负向中亲杂种优势的组合5个，其中97  S组合的中亲优势率最高，为24.08%；S  97组合最低，为-12.69%。正向高亲杂种优势组合有6个、负向高亲杂种优势组合有6个，其中97  S组合的高亲优势率最高，为15.95%；S  J组合最低，为-19.44%。上述结果表明，皱纹盘鲍不同选育系之间的交配组合，杂种优势率差异很大，因此，通过组配实验，将杂种优势率高的交配组合选择出来应用于生产，可望显著提高目标性状的产量。 对早期发育阶段各生长期壳长性状，亲本一般配合力（GCA）、各杂交组合间特殊配合力（SCA）以及正反交（REC）效应值进行方差分析，结果表明：各亲本GCA差异显著，说明各选育群体存在显著的遗传差异，其中汕头选群“S”在测量的各个生长期均为正值且显著大于其它各亲本；特殊配合力（SCA）以及正反交（REC）效应值较大在各杂交组合间存在显著差异，说明在早期生长发育阶段非加性遗传效应（显性和上位效应）占主导地位。综合各个生长期亲本GCA和杂交组特殊配合力（SCA）以及正反交（REC）效应值，杂交组合97×S在早期生长阶段不仅有较高SCA值而且两个亲本也具有较大的GCA值，表明选育系97和S较适宜作为杂交亲本使用。 （2）大连“98”选群与汕头“S”选群进行2×2因子设计的群体杂交实验，比较了各交配组合早期存活相关性状如受精率、孵化率、变态率以及壳长性状，评价了两个方向杂交组合平均以及不同方向杂交组合的中亲杂种优势率。结果表明早期发育阶段各组合间的受精率无显著差异，而孵化率、变态率等两个杂交方向平均的中亲杂种优势率为5.49%与12.53%，高于壳长性状的优势率（0.936-1.534%）。方差分析结果表明不同方向的杂交组合在早期发育阶段存活相关性状以及壳长性状存在显著差异。孵化率、变态率性状，S×98的中亲杂种优势率分别为13.21%与21.10%，均高于98×S的-3.84%与3.85%；而第10和25d壳长性状，S×98的中亲杂种优势率为1.14%与-2.52%，低于98×S的1.93%与4.41%。 为进一步评价“98”选群与“S”选群不同交配组合在不同温度条件下的生长，进行了基因型与环境的互作研究。从“98”选群与“S”选群的4个交配组合中分别取5月龄幼鲍100头，各组合随机分成3组，每组1个重复，分别于12°C、16°C和 22°C温度条件下进行培育，比较各交配组合基因型与温度对幼鲍生长的影响。不同温度条件下，各组合壳长生长的方差分析结果表明，基因型和温度都能够对幼鲍生长以及最终壳长产生极显著的影响（P < 0. 01），它们的交互作用也达到显著水平（P < 0.05）。杂交子代的幼鲍壳长在12°C、16°C和 22°C温度条件下均表现出杂种优势，双向杂交的中亲杂种优势率分别为5.32%、5.55%和0.03%，表明低温条件（12°C），比高温条件（22°C）下有更强的杂种优势。汕头“S”选群的早期孵化率、变态率、生长性状以及低温条件下幼鲍生长性状的单亲杂种优势率分别为16.64%、42.49%、3.42~5.79%和5.73~9.15%，单亲杂种优势率较大，表明可通过杂交手段，显著地改良汕头“S”选群在早期发育阶段的生长速度、存活率以及幼鲍期的生长性状。本研究的结果支持了Lerner（1954）杂种优势的基因与环境互作学说。 5. 皱纹盘鲍幼鲍的中间培育技术研究 （1）对南方越冬方式的评价 目前，每年的11月前后，将6-7月龄幼鲍运往南方的闽东、闽中、闽南沿海越冬，翌年4月至6月再运回到北方（大连、山东半岛）的养殖模式已经普遍应用于皱纹盘鲍的实际生产，为评价南方越冬的幼鲍培育方式，本研究分别以不同幼鲍材料在闽东三都海湾进行了越冬培育实验。 选择生产上壳长分别为18.37 ± 1.28 mm、15.89 ± 1.10 mm、14.55 ± 1.10 mm与10.59 ± 0.84 mm的幼鲍进行了为期6.5个月的越冬培育，实验结束时，存活率分别为95.56 ± 2.21%、90.55 ± 1.96%、83.97 ± 1.63%与63.30 ± 2.79%。回归分析表明，供试幼鲍在实验起始时的壳长与越冬阶段的存活率成正相关（P = 0.018 < 0.05）。该结果表明，提高幼鲍的规格可显著提高皱纹盘鲍的越冬成活率，因此对于实际生产而言，采取适当措施提高皱纹盘鲍越冬苗种的规格将大幅增加生产的收益，而采用生长速率快的品种、品系或提早采苗均可实现该目标。综合各规格组幼鲍，幼鲍在南方开放性水域进行越冬培育的平均存活率较高，可达到91.38±0.01%，从幼鲍南方越冬的存活曲线可以看出，幼鲍的死亡主要集中在从大连运至福建某地后的15天内，出现死亡高峰的原因可能是由于运输过程的胁迫。此外，2月及4月中下旬水温出现显著降低或回升时也有较明显的死亡出现。该部分结果，对皱纹盘鲍幼鲍的养成管理有指导意义，可以通过合理安排越冬时间、避开死亡的敏感期等措施减少苗种越冬阶段的死亡量。 以中国大连野生群体繁育的子一代为亲本（10♀，10♂），以群体交配的方式繁育F2代个体为实验材料，分别于南方海区以及北方室内升温水方式下进行生长、存活比较，结果表明南方越冬培育方式下，幼鲍壳长的日增长率为81.37-108.89 µm•day-1，与北方室内升温培育条件相比，壳长生长提高了1.08 ~ 1.68倍；而存活率无显著差异。皱纹盘鲍幼鲍南方越冬方式的优势主要体现在鲍鱼幼鲍的生长速度加快，同时节约养殖场的能耗 （2）幼鲍培育过程中的养殖密度与分选效应评价 以3种规格皱纹盘鲍幼鲍为材料比较幼鲍在4个培育密度以及分选或混养条件下壳长的平均日生长及特定生长率。在南方越冬培育方式下实验进行106天，多因素方差分析结果表明实验初始幼鲍的壳长以及培育密度对壳长的生长有显著影响，而且密度效应在不同幼鲍起始规格组中有不同表现；分选没有能够提高不同规格组的生长。本研究的结果对皱纹盘鲍幼鲍的越冬培育有一定的指导作用。

皱纹盘鲍生长和抗逆相关新基因的初步研究

在刘晓研究员已构建的皱纹盘鲍全长cDNA文库及克隆随机测序的结果基础上，分析发现了皱纹盘鲍胸腺肽β（Tβ）cDNA全长，该序列全长487bp，生物信息学分析显示其含有一个135bp的开放阅读框（ORF），编码一个含44个氨基酸的蛋白质分子，另外其5'和3'非翻译区长度分别是69bp和283bp，3'端非翻译区具有AATAAA mRNA加尾信号及PolyA寡聚腺苷酸尾巴。采用荧光定量PCR的方法研究皱纹盘鲍Tβ的组织特异性发现，Tβ在各组织中均有分布，但在外套膜中高表达，推测和其组织结构中富含参与免疫分泌的颗粒有关。利用荧光定量PCR检测感染鳗弧菌后皱纹盘鲍腹足肌中Tβ在不同时间点的转录表达发现，Tβ基因表现出具有显著差异的时间依赖性，12h后Tβ基因的表达量明显升高，且在处理后24h达到最高值，然后表达量开始回落，至处理后72h，Tβ表达量基本降至初始值。推测皱纹盘鲍在受到病原菌侵染后Tβ基因表达量上调可能是由于Tβ基因参与了皱纹盘鲍的免疫反应，它可能在皱纹盘鲍的抗逆机制中发挥着重要作用。 发现了一个在皱纹盘鲍大小个体中差异表达的长1555bp含有完整3’端的新基因片断，暂命名为TH。利用荧光定量PCR检测皱纹盘鲍RwRh、J1Rh、J1Jm、RwJm 4个家系大小个体中TH基因的差异表达，发现其在大个体中的表达量显著高于小个体，推测其可能与皱纹盘鲍生长速度有某种关联。荧光定量PCR对皱纹盘鲍TH基因时空差异表达的研究发现，其在发育过程中的表达呈现出一定的规律性，即在围口壳幼虫期前始终保持较低水平的表达，当围口壳形成后表达量急剧增加，至幼鲍时达到最高值，在成鲍中也维持较高水平的表达，提示该基因可能调控壳的发育。同时，皱纹盘鲍TH基因具有组织特异性表达，在外套膜中的表达量显著高于其他组织，推测和其组织结构中富含参与壳形成的颗粒有关。另外还比较了皱纹盘鲍RwRh、J1Rh、J1Jm、RwJm 4个家系中TH基因的差异表达，结果发现在这4个家系中的相对表达呈现出一定的规律，即J1Rh＞RwRh＞RwJm＞J1Jm，可能有助于解释家系之间生物学性状上的差异。