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21.
基于形态参数和AFLP标记的文蛤(Meretrix meretrix)不同地理群体遗传变异分析 总被引：10，自引：3，他引：7
应用方差分析和Tukey多重比较对文蛤的辽宁(LN)、山东(SD)、江苏(JS)、广西(GX)4个自然地理群体的7个壳形态参数进行了研究,结果发现,SD和JS群体间差异不显著,LN和Gx群体差异不显著,Gx群体与SD和JS群体间差异显著(P<0.05).利用4对引物组合对这4个群体进行了AFLP扩增,共得到236个位点,其中特有位点14个,这些特有位点可作为群体鉴别的特征性标记.遗传多样性分析表明,4个文蛤群体的遗传多样性水平均较高,而以Gx群体最高,Nei's基因多样性指数和Shannon's多样性指数分别达到0.2636、0.3961,sD群体最低.分别为0.2308、0.3462.从群体间遗传距离和NJ法构建的亲缘关系谱系图来看,LN和SD群体的遗传距离最近(0.0394),首先聚在一起,而Gx群体与其他3个群体间都较远(0.1271-0.1586),单独分出一支,这说明Gx群体已发生了明显的遗传分化,用它与其他3个群体杂交可望较大幅度地提高遗传多样性水平. 相似文献
22.
Increasing evidence indicates that transforming growth factor β(TGF-P) signaling pathways play many important roles in the early development of mollusks.However,limited information is known concerning their detailed mechanisms.Here,we describe the identification,cloning and characterization of two Smad genes,the key components of TGF-P signaling pathways,from the Pacific oyster Crassostrea gigas.Sequence analysis of the two genes,designated as cgi-smad1/5/8 and cgi-smad4,revealed conserved functional characteristics.The two genes were widely expressed in embryos and larvae,suggesting multiple roles in the early development of C.gigas.The mRNA of the two genes aggregated in the D quadrant and cgi-smad4 was highly expressed on the dorsal side of the gastrula,indicating that TGF-P signaling pathways may be involved in dorsoventral patterning in C.gigas.Furthermore,high expression levels of the two genes in the shell fields of embryos at different stages suggested important roles for TGF-P signaling pathways in particular phases of shell development,including the formation of the initial shell field and the biomineralization of larval shells.The results of this study provide fundamental support for elucidating how TGF-P signaling pathways participate in the early development of bivalve mollusks,and suggest that further work is warranted to this end. 相似文献
23.
engrailed基因属于同源异形基因家族成员,在许多动物的分节、附肢发育、神经系统发育和贝壳形成过程中发挥作用。本研究克隆了长牡蛎两个engrailed同源基因,命名为cgi-eng1和cgi-eng2。序列分析表明,两个基因均具备典型engrailed基因保守的5个EH结构域。利用整装原位杂交技术检测了cgi-eng1和cgi-eng2在贝壳形成的关键时期早期D形幼虫时期的表达情况。结果显示,cgi-eng1和cgi-eng2 m RNA高表达于贝壳外缘,可能与早期贝壳形成过程有关。此外,两个基因的在贝壳外缘的表达模式亦有区别,提示两个基因的功能可能存在一定程度的分化。本研究首次系统鉴定了长牡蛎engrailed基因的成员,并发现它们可能均参与幼虫贝壳形成,研究结果有助于加深对贝类早期发育及贝壳形成的理解。 相似文献
24.
Effects of temperatures and salinities on oxygen consumption and ammonia-N excretion rate of clam Meretrix meretrix were studied in laboratory from Oct. 2003 to Jan. 2004. Two schemes were designed in incremented temperature at 10, 15, 20, 25℃ at 31.5 salinity and in incremented salinity at16.0, 21.0, 26.0, 31.5, 36.0, and 41.0 at 20℃, all for 8-10 days. From 10 to 25℃, both respiration and excretion rate were increased. One-way ANOVA analysis demonstrated significant difference （P〈0.01） in physiological parameters in this temperature range except between 15 and 20℃. The highest Q10 thermal coefficient value （12.27） was acquired between 10 and 15℃, and about 1 between 15 and 20℃, indicating M. meretrix could well acclimate to temperature changes in this range. Salinity also had significant effects on respiration and excretion rate （P〈0.05）. The highest values of respiration and excretion rate of M. meretrix were recorded at 16.0 salinity （20℃）. These two physiological parameters decreased as salinity increased until reached the minimum Q10 value at 31.5 （20℃）, then again, these parameters increased with increasing salinity from 31.5 to 41.0. M. meretrix can catabolize body protein to cope with osmotic pressure stress when environmental salinity is away from its optimal range. No significant difference was observed between 26.0 and 36.0 in salinity （P〉0.05）, suggesting that a best metabolic salinity range for this species is between 26.0 and 36.0. 相似文献
25.
采用线粒体 COI 基因和核糖体第一内转录间隔区 ITS-1基因,对荣成(RC)和即墨(JM)2个魁蚶(Scapharca broughtonii Schrenck)野生地理群体及一个人工繁育的即墨子代(JZ)群体,进行遗传多样性和遗传结构分析,探讨即墨人工繁育的子代作为荣成魁蚶底播增殖苗种的可行性。分子方差分析(AMOVA)结果表明,3个群体的遗传差异主要存在群体内。荣成野生群体和即墨野生群体间的Fst值,基于COI基因和ITS-1基因分别为0.1678和0.1193,表明荣成野生群体与即墨野生群体之间存在中等程度的遗传分化。单倍型多样性和核苷酸多样性分析结果表明,人工繁育的即墨子代群体的遗传多样性明显降低。荣成野生群体与即墨子代群体之间的遗传差异,较之与即墨野生群体间的遗传差异更大。如果采用即墨子代在荣成底播,可能会对荣成野生魁蚶野生群体的遗传结构产生一定影响,因此,采用即墨人工繁育子代作为荣成魁蚶底播增殖的苗种来源时必须十分慎重,并在苗种繁育时尽量采用大群体有效亲本。 相似文献
26.
ＩＮＴＲＯＤＵＣＴＩＯＮＰｕｆｆｅｒｆｉｓｈｅｓｏｆｔｈｅｇｅｎｕｓＴａｋｉｆｕｇｕ (Ｔｅｔｒａｏｄｏｎｔｉｆｏｒｍｅｓ,Ｔｅｔｒａｏｄｏｎｔｉｄａｅ)ａｒｅｍａｉｎｌｙｄｉｓｔｒｉｂｕｔｅｄａｌｏｎｇｔｈｅｃｏａｓｔａｌｒｅｇｉｏｎｓｏｆＣｈｉｎａ ,ＪａｐａｎａｎｄＫｏｒｅａａｎｄａｒｅｃｏｍｍｅｒｃｉａｌｌｙｉｍｐｏｒｔａｎｔｔｏｔｈｅｓｅｃｏｕｎ ｔｒｉｅｓ .Ｏｖｅｒ 2 0ｓｐｅｃｉｅｓｈａｖｅｂｅｅｎｒｅｃｏｒｄｅｄｉｎｔｈｅＹｅｌｌｏｗＳｅａａｎｄｔｈｅＥａｓｔＣｈｉｎａＳｅａ (Ｃｈｅｎｇ… 相似文献
27.
The precise and accurate knowledge of genetic parameters is a prerequisite for making efficient selection strategies in breeding programs.A number of estimators of heritability about important economic traits in many marine mollusks are available in the literature,however very few research have evaluated about the accuracy of genetic parameters estimated with different family structures.Thus,in the present study,the effect of parent sample size for estimating the precision of genetic parameters of four growth traits in clam M.meretrix by factorial designs were analyzed through restricted maximum likelihood(REML) and Bayesian.The results showed that the average estimated heritabilities of growth traits obtained from REML were 0.23–0.32 for 9 and 16 full-sib families and 0.19–0.22 for 25 full-sib families.When using Bayesian inference,the average estimated heritabilities were0.11–0.12 for 9 and 16 full-sib families and 0.13–0.16 for 25 full-sib families.Compared with REML,Bayesian got lower heritabilities,but still remained at a medium level.When the number of parents increased from 6 to 10,the estimated heritabilities were more closed to 0.20 in REML and 0.12 in Bayesian inference.Genetic correlations among traits were positive and high and had no significant difference between different sizes of designs.The accuracies of estimated breeding values from the 9 and 16 families were less precise than those from 25 families.Our results provide a basic genetic evaluation for growth traits and should be useful for the design and operation of a practical selective breeding program in the clam M.meretrix. 相似文献
28.
温度对硬壳蛤Mercenaria mercenaria(Linnaeus，1758)呼吸排泄的影响 总被引：5，自引：2，他引：5
于 2 0 0 2年 1 1月— 2 0 0 3年 4月 ,采用Winkle滴定法和次溴酸盐氧化法对硬壳蛤呼吸排泄进行了研究。结果表明 ,在 5— 35℃温度范围内 ,温度和体重对硬壳蛤 (壳长 0 5— 6cm ,软体部干重 0 0 0 34— 0 5 9g)的耗氧率和排氨率均有显著影响 (P <0 0 5 ) ,其单位体重耗氧率在2 0— 30℃之间达到最大值 ,且随着硬壳蛤个体的增大而下降 ;不同温度下硬壳蛤个体耗氧率OR[mgO2 /(ind·h) ]与软体部干重W(gDFW)之间的关系可用方程OR =aWb 表示 ,其中a值在0 0 4— 0 70之间 ,b值在 0 45— 0 65之间。硬壳蛤的排氨率 温度曲线呈单峰型 ,其单位体重排氨率在 2 5℃附近达到最大值 ,且随着硬壳蛤个体的增大而下降。不同温度下硬壳蛤个体排氨率NR[μgNH4 N/(ind·h) ]与软体部干重W(gDFW)之间的关系可用方程NR =aWb 表示 ,其中a值在 1— 2 7之间 ,b值在 0 40— 0 75之间。硬壳蛤呼吸排泄的氧、氮比在 5℃时最大 ,随后有下降趋势 ,其比值在 1 0— 80之间。 相似文献
29.
采用室内模拟的方法，对盐度、饵料、底质和温度对硬壳蛤稚贝成活率和生长率的影响进行了研究。结果表明，硬壳蛤稚贝存活和生长的适宜盐度范围为18－42，最适盐度范围为24－36。从稚贝成活率看，几种单胞藻的饲育效果顺序为：等鞭金藻＞美国扁藻＞混合藻＞亚心形扁藻＞大溪等鞭金藻＞三角褐指藻＞小球藻＞中肋骨条藻；但从稚贝日生长率看，几种单胞藻的饲育效果顺序为：混合藻＞等鞭金藻＝美国扁藻＝亚心形扁藻＞大溪等鞭金藻＞三角褐指藻＞小球藻＞中肌骨条藻。硬壳蛤对底质环境有一定的选择性，稚贝在纯砂底质中的成活率和日生长率均高于在纯海泥底质中，但砂的粒径大小对稚贝成活率和日生长率没有明显影响。硬壳蛤稚贝具有很强的耐高温能力，在室内控温条件下，能够耐受30－35℃的高温，但在室外自然温度条件下，当温度为21．8－35．4℃（平均为30．1℃）时，稚贝成活率却很低，无砂情况下只有32％，有砂情况下为零。 相似文献
30.