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1.
Ten enzymatic systems were analyzed to determine allozyme genetic differentiation among three hatchery strains (A, B and C) of white shrimp, Penaeus (Litopenaeus) vannamei, commonly used in shrimp farming in northwest Mexico. A wild population from northern Sinaloa was used as a reference. Fifteen loci were detected, nine of which were polymorphic (ACP-1*, ACP-2*, AKP-2*, EST-2*, EST-3*, EST-4*, EST-5*, LAP*, and LDH*). Polymorphism of A, B and C were 53, 53, and 40%. The mean observed heterozygosity per locus was 0.071, 0.093, and 0.050 without any significant difference among them or with respect to the wild population (0.056). In all samples observed heteroxygosity was smaller than expected. The mean number of alleles per locus was 1.8 in A and 1.87 in both B and C. Strain A was the only sample without rare alleles. Only EST-3* and LAP* of strain A were in Hardy-Weinberg equilibrium; the other loci were in disequilibrium in all samples. High inbreeding values and heterozygote deficiencies were detected in all samples. Distribution of allelic frequencies was heterogeneous among the samples (G-test), involving all polymorphic loci and suggesting a genetic differentiation. According to Fst, a moderate genetic differentiation (7.4%) was detected among the samples. Greater differences were between strains A and C. Based on genetic distance, the samples were grouped into two pairs, B–C and A-wild. Strain A is a young strain related to the wild sample, whereas strains B and C have a different geographic origin than the wild sample.  相似文献   

2.
We conducted a population genetic analysis of Penaeus stylirostris to describe the genetic variability in two wild samples (Guaymas and Peñasco) and in two cultivated strains (A and B), and to determine the relationship among samples. Seventeen enzymatic systems and general proteins were used to visualize 31 loci. Of the 31 loci, 11 polymorphic loci (35%) were detected in all the organisms, with an average heterozygosity of 0.10 and an average of 1.8 per locus. There were no significant differences among the four samples of observed heterozygosity or percentage of polymorphic loci. According to Hardy–Weinberg, both cultivated strains showed disequilibrium in more loci than the wild samples. Guaymas showed linkage disequilibrium in five pairs of polymorphic loci, Peñasco samples in two pairs, A in seven pairs, and B in nine pairs. Peñasco and both cultivated lineages showed evidence of recent reductions in their effective populations size. Based on the comparisons of Fst values, and the distribution of the allelic frequencies, the cultivated strains were significantly different from the two wild populations. There is evidence that strain B originated from A and the discrepancies between the strains are probably the result of genetic drift and a founder effect.  相似文献   

3.
邢德  李琪  张景晓 《水产学报》2017,41(12):1838-1846
为了探讨壳白长牡蛎人工选育对群体遗传变异的影响,实验利用4个多重PCR组合共10个微卫星标记分析了连续3代壳白长牡蛎人工选育群体和野生群体及基础群体的遗传多样性。结果发现,6个群体的平均等位基因数量为7.2~12.6,等位基因丰度为6.8~11.0,期望和观测杂合度分别为0.672~0.769和0.486~0.542;与野生群体相比,3代选育群体的平均等位基因数显著降低,但平均期望杂合度并无显著差异。哈迪—温伯格平衡检验结果显示,在60个群体—位点组合中有39个群体—位点组合显著偏离哈迪—温伯格平衡,近交系数F_(is)范围为0.215~0.342。群体间遗传分化指数F_(st)范围为0.005~0.076,处于中—低等的遗传分化水平。研究表明,虽然连续选育对群体的遗传多样性和遗传分化造成了一定程度的影响,但人工选育群体依然表现为较高的遗传多样性,仍可以一定的选择压力对选育群体进行人工选育。  相似文献   

4.
草鱼野生与选育群体遗传变异微卫星分析   总被引:3,自引:1,他引:2  
为探究经过2个选育世代后选育群体遗传多样性和遗传结构的变化,实验采用多重PCR技术对4个野生草鱼群体(邗江、九江、石首、吴江)和2个选育群体(F1和F2)进行了微卫星序列遗传变异分析。结果显示,6个草鱼群体遗传多样性水平较高,2个选育群体除了平均等位基因数外,其他遗传多样性参数均小于4个野生群体。哈迪—温伯格平衡(Hardy-Weinberg equilibrium)检测显示,在120个群体—位点组合中有62个位点显著偏离哈迪—温伯格平衡,62个群体—位点组合中只有11个组合其近交系数值为负值,其余的51个组合的Fis均为正值。6个草鱼群体AMOVA分析结果显示,3.75%的变异来自于群体间,96.25%的变异来自于群体内,整体的遗传分化指数值为0.038。进一步分析各个群体间Fst,只有石首群体与F1、F2群体之间的Fst大于0.05,处于中等分化,其余群体间分化程度较低,且F2群体与4个野生群体之间Fst比F1群体与4个野生群体之间的Fst大。奈氏标准遗传距离分析结果显示,2个选育群体与野生群体之间的遗传距离大于野生群体之间的遗传距离。基于Dn建立的UPGMA系统发育树得出了相同的结果,即2个选育群体与野生群体之间的亲缘关系比4个野生群体之间的亲缘关系要远。研究表明,经过2个世代选育后,相比4个野生群体,2个选育群体遗传多样性虽有部分下降,但仍处于较高的水平,2个选育群体的遗传结构已发生变化,但其遗传分化程度尚不明显。本研究结果为制定出更加完善有效的选育方案提供了重要参考。  相似文献   

5.
郝婧薇  华昕彤  傅松哲  周灿  刘鹰  胡惠秩 《水产学报》2023,47(3):039416-039416
为了阐明引起急性肝胰腺坏死病(acute hepatopancreatic necrosis disease, AHPND)副溶血性弧菌的接合型质粒在对虾养殖环境中的遗传多样性,实验从中国5个沿海省份的虾场收集了100个底泥样品,以质粒上编码接合转移蛋白的保守基因为目标,利用PCR法检测相关质粒的存在情况,并对质粒进行测序。结果显示,100个样品中有39个样品含有质粒的接合转移蛋白片段。从100个底泥样品中分离出15株副溶血性弧菌,其中13株含有1~2个质粒。质粒序列测序结果显示,这些质粒可分为8种类型/谱型,其中7种不携带pirAB,但均含有编码接合转移的基因簇。根据分离副溶血性弧菌携带质粒的8种谱型,分别选择8株副溶血性弧菌进行凡纳滨对虾攻毒实验,发现这些菌株对凡纳滨对虾的毒性有显著差异,实验虾死亡率为15%~100%。只有pirAB阳性菌株会对实验虾产生AHPND症状,死亡率为100%。对质粒组成进行分析表明,质粒之间遗传物质交换频繁,大部分质粒的遗传组成都来自一个183 kb的超大质粒pVP2HP。综上,本实验通过探究对虾养殖场底泥中结合性质粒的多样性,增强了人们对副溶血性弧菌...  相似文献   

6.
In the Mediterranean area, wild fish have often been suggested as either the reservoirs of the causative agents or at least the carriers of the pathogens responsible for disease outbreaks in cultured fish. However, no epidemiological investigations on actual pathogen/disease interactions between farmed and wild fish have been conducted even for the most important fish pathogens. Only sporadic isolations and identifications of various pathogens in wild fish have been done and real associations with the pathological conditions that exist within the farm environment and vice versa have not been established. Monogenean ectoparasite Sparicotyle chrysophrii and isopod Ceratothoa oestroides are commonly found in the Mediterranean cage-reared sea bream and sea bass and in the surrounding wild fish population. Both species were recognized as pathogens that seasonally inflict serious losses in fingerlings and juveniles of sea bream and sea bass, being potentially propagated and exchanged during wild and caged fish interaction. In order to evaluate the degree of pathogens transfer between wild and farmed fish, we investigated genetic population structures of these two important parasitic pathogens inferred by mtDNA cytochrome oxidase I locus. Parasites isolated from wild and farmed fish on the two most productive Adriatic fish farms showed genetic heterogeneity, contradicting widely accepted hypothesis of cross-contamination, at least in case of S. chrysophrii and C. oestroides. As far as we know, this is the first report that in a study of pathogen transfer molecular evidence was employed to asses the genetic population structure of shared parasites.  相似文献   

7.
河蚬微卫星引物筛选及洪泽湖野生群体遗传结构分析   总被引:3,自引:0,他引:3  
丁怀宇  姜虎成  冯建彬  孙骥  李家乐 《水产学报》2011,35(11):1624-1632
利用磁珠富集法筛选了河蚬10对中高度多态性的微卫星引物,并分析了洪泽湖河蚬4个野生群体的遗传结构.结果表明,每个群体至少有4个位点经Bonferroni校正后显示杂合不足,显著偏离了Hardy -Weinberg平衡(P<0.013);4个群体平均期望杂合度均大于0.752,显示出较高的遗传多样性水平,蒋坝、临淮群体遗传多样性高于高良涧和老子山群体;突变-漂移平衡分析结果显示,4个群体在IAM模型下偏离了突变-漂移平衡,高良涧群体在TPM模型下偏离了突变-漂移平衡,且表现杂合过剩,说明少数群体即将或曾经经历瓶颈效应,群体数量已出现波动;群体间AMOVA分析表明,洪泽湖河蚬群体间遗传分化程度较低(FST=0.017 7<0.05),仅有1.77%的变异来自群体间,并没有形成显著的遗传结构,在种质资源保护和管理上可视作一个单元,这为河蚬种质资源保护和合理开发利用提供了理论指导.  相似文献   

8.
赵博文  李琪  王九龙  于红 《水产学报》2020,44(2):195-205
黑色素是一种广泛存在于动物界的生物色素,而酪氨酸酶被认为是一种重要的调控黑色素合成的关键酶。实验以3种壳色的长牡蛎选育品系为材料,使用PCR-SSCP的方法对长牡蛎酪氨酸酶基因CgTyr1进行SNP分型筛选,将突变位点与不同壳色性状进行关联分析。结果显示,酪氨酸酶基因的外显子上存在23个SNP位点,其中11个SNP位点与壳色性状极显著相关;在这11个S N P位点中,检测到有3个S N P位点为有义突变(c.591C/T、c.632G/A和c.1155T/C),分别导致不同的氨基酸突变(Ala122Val、Gly136Ser和Phe310Ser);利用极显著关联的11个SNP位点,为每种壳色群体建立了1种单倍型,并在验证组中得到了确认。研究表明,长牡蛎酪氨酸酶基因的单个碱基突变和以此构建的单倍型与壳色性状存在显著的关联。本研究筛选出的SNP位点和构建的单倍型为长牡蛎壳色品系选育提供了重要的参考资料。  相似文献   

9.
为明确不同选育群体中间球海胆的遗传多样性和遗传结构,利用SSR-seq技术和15个微卫星位点,对1个家系选育群体(FP)、1个群体选育群体(IP)和1个未经选育的普通养殖群体(CP)的遗传多样性及遗传结构进行了分析。结果显示,15个微卫星位点共检测出112个等位基因,FP、IP、CP 3个群体的平均观测等位基因数(Na)分别为5.077、5.133和6.133个,平均有效等位基因(Ne)分别为2.816、2.873和3.638个,平均观测杂合度(Ho)分别为0.522、0.441和0.501,平均期望杂合度(He)分别为0.595、0.599和0.667,平均多态性信息含量(PIC)分别为0.546、0.543和0.623。家系选育群体(FP) He与Ho的差值(0.073)低于IP (0.158)和CP (0.166),平均固定指数(F)(0.115)低于IP (0.248)和CP (0.246)。3个群体间遗传分化系数(Fst)介...  相似文献   

10.
王琼  李健  何玉英 《水产学报》2023,47(3):039610-039610
中国明对虾是我国最重要的养殖虾类之一。性成熟后的中国明对虾在生长和体色上表现出性别二态性。为了探查基因组上潜在的性别分化相关区域,对中国明对虾进行了全基因组重测序研究。分别使用中国明对虾基因组和其近缘物种凡纳滨对虾的基因组作为参考基因组,计算了雌雄中国明对虾之间的遗传分化指数Fst,以筛查基因组上的性别分化相关区域。当使用中国明对虾参考基因组时,有约89%的中国明对虾测序读段全部或部分比对到中国明对虾参考基因,覆盖度大约为84%。基因组上Fst出现较多杂乱的峰,其中LG5的Fst值整体呈升高的趋势,另外LG13、LG17及LG35均有Fst指数相对较高的区域。而当使用凡纳滨对虾参考基因组时,有约60%的中国明对虾测序读段全部或部分比对到凡纳滨对虾参考基因,覆盖度约为52%。Scaffold 2550和Scaffold 3683上分别有2个最显著的峰。将雌雄中国明对虾转录组测序数据与凡纳滨对虾的参考基因组比对后,获得了中国明对虾的粗略表达谱,挖掘出了丰富的差异表达基因。分析了前述2个Scaffold上...  相似文献   

11.
利用筛选的13对草鱼多态性微卫星标记,开展了2011至2015年长江中游草鱼亲本增殖放流对野生群体遗传多样性的影响评估。通过对各位点的遗传多样性分析,13个微卫星位点的多态信息含量为0.8622(0.657~0.950),基因多样度为0.8555(0.675~0.936)。15个群体的有效等位基因数为7.4503~10.1536,等位基因丰度为11.483~15.204,说明15个草鱼群体的遗传多样性水平总体较高。遗传分化指数分析表明,群体间不存在显著遗传分化(FST5%)。通过贝叶斯聚类分析和主成分分析可将草鱼群体分为4个组群,根据分组结果以及来源划分分别对草鱼群体进行AMOVA分析,发现遗传变异大部分来自于群体内个体间,组间及组内群体间的分化水平较低(FCT5%,FSC5%),与FST分析结果一致。研究表明,当前草鱼亲本增殖放流模式对野生群体遗传结构影响不明显。  相似文献   

12.
郭婷  宋娜  刘淑德  涂忠  胡发文  高天翔  陈健 《水产学报》2020,44(12):1976-1986
基于线粒体DNA控制区高变区部分序列和4对微卫星标记,对大泷六线鱼放流群体及自然海域群体的遗传多样性与遗传差异进行了比较分析。线粒体DNA控制区序列分析的结果显示,413尾个体共检测到单倍型117种,其中仅Hap_3、Hap_7和Hap_17为共享单倍型,占总单倍型数目的2.5%;放流、野生群体特有单倍型分别为20种和66种,分别占总单倍型数的17.09%和56.41%,放流群体特有单倍型数明显低于野生群体;放流群体和野生群体核苷酸多样性分别为0.005 1~0.006 7和0.005 8~0.007 5,单倍型多样性分别为0.856 7~0.949 9和0.883 1~0.954 9,遗传多样性均较高。微卫星标记分析结果显示,放流、野生群体平均等位基因数(Na)分别为13~44和13~27,平均多态信息含量为0.885 6和0.874 0,均具较高的遗传多态性;群体遗传结构分析结果表明,放流、野生群体间遗传分化水平较低。研究表明,山东近海大泷六线鱼放流群体与野生群体均具有较丰富的遗传多样性,且遗传结构未存在显著的群体分化。  相似文献   

13.
为研究在养殖过程中降低鱼粉用量的同时保持凡纳滨对虾良好的生长性能和抗逆能力,实验在含10%鱼粉的基础饲料中,分别添加酶解豆粕(PSM) 0%(A)、2.5%(B)、3.5%(C)、4.5%(D)、5.5%(E)制成5组等氮等能饲料,分别投喂初始体质量为(0.45±0.02) g的凡纳滨对虾幼虾8周,检测对虾生长性能及抗胁迫机能。结果显示,8周养殖实验结束后,各实验组对虾的终末体质量为14.65~15.38 g/尾,各组间对虾终末均重、成活率和饲料系数指标均无显著性差异;A组对虾肌肉粗蛋白质含量显著低于其他各实验组;C组、D组和E组对虾肌肉粗脂肪含量显著高于A组;各组间灰分和水分均无显著性差异;D组和E组对虾肝胰腺蛋白酶、淀粉酶、脂肪酶、血清溶菌酶和血清总超氧化物歧化酶活性(T-SOD)均显著高于A组;A组对虾血清丙二醛(MDA)含量显著高于D组和E组。人工急性感染高剂量副溶血性弧菌的胁迫实验中,A组对虾在弧菌感染48和60 h时的累积死亡率均显著高于D组对虾同期的累积死亡率;低剂量副溶血性弧菌人工急性感染后,在凡纳滨对虾鳃组织中检测Toll受体、免疫缺陷(IMD)和溶菌酶3种免疫相关基因的表达量,结果显示,对虾Toll受体、IMD和溶菌酶mRNA表达量最大峰值分别出现在添加酶解豆粕的C组、B组和D组,峰值出现时刻分别为感染后24、42和24 h。研究表明,含10%鱼粉的饲料中添加0%~5.5%酶解豆粕对凡纳滨对虾的生长性能改善效果不显著,酶解豆粕会显著提高凡纳滨对虾肌肉粗蛋白质含量和粗脂肪含量;显著降低对虾血清丙二醛含量;同时也会显著改变凡纳滨对虾对弧菌的抵抗力及其免疫相关基因的时空表达,酶解豆粕添加量达到4.5%时可使养殖的凡纳滨对虾获得最佳的抗弧菌能力。  相似文献   

14.
利用7个微卫星标记分析了6个凡纳滨对虾家系的亲本(G0)及其后代(G1)的基因型分离情况,同时对G0和G1的所有座位期望杂合度进行配对比较分析,并且通过对G1群体每个位点的F-statistics分析检验群体的遗传分化,以期对凡纳滨对虾育种进行遗传监测。结果表明:共检测到44个等位基因。G0和G1的平均每个座位的等位基因数目分别为6.14和6.27,平均期望杂合度为0.786和0.733,平均多态性信息含量为0.709和0.695。7个微卫星座位的累计排除概率为0.99,并且在有亲本存在的情况下,能够将6个家系分开。G0与G1的所有座位期望杂合度的配对比较分析结果表明G0平均期望杂合度要显著高于G1(P<0.01)。G1各座位的遗传分化指数FST在0.270 3~0.465 4,平均分化系数为0.358 4。说明亚群间属于高度遗传分化。最后,根据6个家系的遗传距离,利用UPGMA法对G1个体聚类分析,结果表明亲缘关系较近的家系A和B以及C和D的相似系数很高分别各聚为一类,E和F分别聚为一类。  相似文献   

15.
Larval rearing of many marine organisms is dependent on the availability of live food. The aim of this study was to optimize larval first feeding for the mud shrimp Upogebia pusilla, by comparing the effectiveness of the two most commonly used live feeds: Brachionus plicatilis and Artemia sp. nauplii. Survival, larval duration, molt synchronism and megalop size were compared using five feeding treatments: Artemia from zoea I to IV (B0), Brachionus during zoea I and Artemia from zoea II to IV (B1), Brachionus during zoea I and II and Artemia during zoea III and IV (B2), Brachionus from zoea I to III and Artemia during zoea IV (B3) and Brachionus from zoea I to IV (B4). The proportion of larvae that reached the megalop stage was 0.00% in treatment B0, 3.33% in treatment B1, 33.33% in treatment B2, 66.67% in treatment B3 and 76.67% in treatment B4. Larvae fed on rotifers until zoea III or zoea IV stages had a higher survival but no differences were found either in time to reach megalop or in megalop size. This study demonstrates that rotifers are essential for the survival and development of U. pusilla early larval stages but that rotifers can be successfully replaced by Artemia nauplii in the zoea IV stage.  相似文献   

16.
健康和患病凡纳滨对虾幼虾消化道菌群结构的比较   总被引:2,自引:1,他引:1  
凡纳滨对虾养殖过程中,早期阶段是病害易感阶段,而消化道菌群结构与对虾健康关系密切。因此,探讨幼虾的消化道菌群尤其是弧菌类细菌与对虾发病的关系对病害有效防治具有重要意义。本实验采用Illumina测序研究了凡纳滨对虾健康和患病幼虾的消化道细菌群落结构,并基于纯培养和16S r DNA,rec A和pyr H基因序列比对,分析了幼虾消化道中弧菌的主要种类组成。结果发现,健康幼虾消化道中α-变形菌纲和厚壁菌门丰度较高,而患病幼虾中γ-变形菌纲、拟杆菌门、放线菌门和β-变形菌纲较高,其中放线菌门丰度差异显著。基于科水平的响应比分析,发现患病幼虾消化道中动性球菌科和噬菌弧菌科的丰度显著降低,而弧菌科的丰度显著升高。相似度分析发现,驱动群落变异的OTU主要来源于弧菌属、海洋杆状菌属、冷杆菌属、假交替单胞菌属以及未分类至属的红杆菌科和微杆菌科。健康幼虾消化道弧菌组成以锡那罗亚州弧菌为主,而患病幼虾消化道弧菌组成以坎氏弧菌为主。尽管健康和患病幼虾消化道内细菌群落结构整体差异不显著,但一些重要类群丰度变化显著,其特征与已知的生态功能一致。  相似文献   

17.
凡纳滨对虾肠道内产消化酶益生菌的分离与筛选   总被引:2,自引:1,他引:1  
为获得具有消化酶活性且安全的益生菌,从凡纳滨对虾肠道中初步分离得到576株细菌,对菌株进行产蛋白酶、淀粉酶和脂肪酶能力的定性及定量测试,筛选出产酶种类多且产酶能力强的菌株11株。对筛选出的11株菌进行了幼虾浸浴实验、药敏性实验和溶血性实验,以评价其生物安全性。将11株菌的菌悬液添加到凡纳滨对虾幼虾的养殖水体中进行浸浴实验,浸浴结束后用鳗弧菌进行刺激,测定不同浸浴组幼虾相关免疫基因的相对表达量,以确定其对幼虾的保护效果。综合消化酶活性、菌株对幼虾的保护效果及生物安全性,筛选得到4株效果较好的菌株。菌株的16S r DNA分子鉴定结果表明,细菌1号、2号和4号分别与芽孢杆菌(Bacillus sp.PCSAS2-38,GQ284495.1)、蜡样芽孢杆菌(B.cereus strain N419,JN400121.1)及苏云金芽孢杆菌(B.thuringiensis strain EA26.1,KC758847.1)的相似性均为100%,9号菌株与荚膜红细菌(Rhodobacter capsulatus strain PSB-03,FJ866782.1)相似性达到99%,为后续益生菌制剂的开发奠定了前期基础。  相似文献   

18.
胡吟胜  段泽林  黄勃  于淑楠  王婷 《水产学报》2013,37(9):1313-1318
为研究野生琼枝与养殖琼枝的遗传差异,利用EST-SSR技术分析了海南东北部地区9株野生和9株养殖琼枝的遗传差异性。结果显示,用5对EST-SSR引物对18个个体的基因组进行扩增,扩增出的片段大小为250~2 500 bp,琼枝野生群体和养殖群体的多态性比例分别为74.29%和70.00%;野生群体之间的平均遗传距离为0.46,养殖琼枝群体之间的平均遗传距离为0.22。聚类分析图显示,在相似系数0.49处,18株群体按野生与养殖分为2大类,在相似系数0.66附近,野生群体分成3类,养殖琼枝群体分为2类,在相似系数0.73附近,野生琼枝群体分成5类,而养殖群体为3类,相似系数越高,野生群体比养殖群体分类单元越多。研究表明,野生琼枝群体的遗传多样性比养殖琼枝群体高。  相似文献   

19.
西北太平洋鸢乌贼种群遗传结构   总被引:4,自引:1,他引:3  
为检测西北太平洋鸢乌贼种群遗传结构,采用线粒体DNA细胞色素b基因(Cytb)序列分析方法对鸢乌贼东海群体、南海群体与菲律宾海群体进行遗传变异分析。结果显示,(1)所有群体总的单倍型多样度与核苷酸多样度分别为0.982±0.006、0.012±0.006;菲律宾海群体对应的遗传多样度均最高,分别为0.973±0.014、0.015±0.008;南海群体与东海群体的单倍型多样度分别为0.959±0.026、0.943±0.031,核苷酸多样度均为0.006±0.003。3个地理群体均具有较高的遗传多样性水平。(2)分子方差分析结果显示,34.6%的遗传变异来自于群体间,群体间遗传分化极显著。两两群体间Fst分析表明,西北太平洋鸢乌贼群体间均具有极显著的遗传分化。构建的单倍型邻接系统树和最小跨度树显示,西北太平洋鸢乌贼群体存在明显的系统发育谱系结构(谱系A、B、C),3个谱系单倍型类群间也存在极显著的遗传分化(Fst=0.735~0.805)。(3)中性检验和核苷酸不配对分析结果均表明,谱系B可能经历过近期群体扩张事件,发生群体扩张的时间在10.3~12.5万年前。综合分析认为,西北太平洋鸢乌贼的种群遗传结构模式及系统发育地理格局模式是由其栖息地海洋环境与更新世气候变化共同塑造的。建议在渔业管理上将3个地理群体划分为3个独立的管理单元。  相似文献   

20.
Microsatellite DNA loci and the Pantophysin locus (Pan I) were used to investigate levels of genetic diversity within farmed strains of Atlantic cod Gadus morhua and to compare them with the wild source population. A total of 282 farmed samples originating from a spawning ground off the south-west coast of Iceland were sampled in the years 2002 and 2003, and 258 wild cod were collected at the same spawning ground in the same years. The farmed strains exhibited a lower mean number of alleles and allelic diversity than the wild samples at the microsatellite loci. Significant differences were observed between wild and farmed samples both in allele and genotype frequencies at the Pan I locus. We argue that the genetic divergence of wild and farmed samples of Atlantic cod may be due to a small number of effective founding breeders contributing to the genetic variation of the farmed strains, inducing a reduction in allelic diversity. We discuss the potential effect of breeding practices on the genetic diversity of Atlantic cod.  相似文献   

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