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1.
Eight microsatellite markers were used to analyze genetic diversity, level of inbreeding, and effective population size of spawner and recaptured populations of Chinese shrimp(Fenneropenaeus chinensis) during stock enhancement in the Bohai Bay in 2013. A total of 254 and 238 alleles were identified in the spawner and recaptured populations, respectively, and the numbers of alleles(N_a) were 8–63 and 6–60, respectively. The numbers of effective alleles(N_e) were 2.52–21.60 and 2.67–20.72, respectively. The polymorphism information content ranged from 0.529 to 0.952. The observed heterozygosity(H_o) values(0.638–0.910 and 0.712–0.927) were lower than the expected heterozygosity(H_e) values(0.603–0.954 and 0.625–0.952), which indicated that the two populations possessed a rich genetic diversity. In 16 tests(2 populations×8 loci), 13 tests deviated from the HardyWeinberg equilibrium. F_(is) values were positive at seven loci and the inbreeding coefficients(F) of the two populations estimated by trio ML were 13.234% and 11.603%, suggesting that there was a relatively high degree of inbreeding. A certain level of inbreeding depression had occurred in the Chinese shrimp population. F_(st) values ranged from 0 to 0.059, with a mean of 0.028, displaying a low level of genetic differentiation in the two populations. Effective population sizes(3 060.2 and 3 842.8) were higher than the minimum number suggested for retaining the evolutionary potential to adapt to new environmental conditions. For enhancement activity in 2014,the ideal number of captured shrimp spawners should have ranged from 7 686 to 19 214 to maintain genetic diversity and effective population size. Further strategies to adjust the balance of economic cost, fishing effort and ideal number of shrimp spawners to maintain a satisfactory effective population size for ensuring the sustainability of Chinese shrimp are proposed. 相似文献
2.
Chinese and Japanese population ofChlamys farreri and their reciprocal hybrids were surveyed in isozyme variability at 13 loci by polyacrytamide gel electrophoresis (PAGE).
Isozyme banding patterns indicated these hybrids were diploid. Loci that were observed as being monomorphic in inbred populations
ofC. farreri were also found to be monomorphic in filial progeny; loci that observed to be polymorphic in parental type generations were
also polymorphic in hybrid generations. Differences existed among allelic frequency of the four types of cross. Within the
reciprocal hybrids the expression of malic enzyme (ME) isozyme was sufficient to distinguishing individual hybrids because
of the band, Rf=0.38. However, there were no noticeable variations among all the samples to differentiate one from another.
Inbreeding was likely to be the main problem in aquaculture. The introduction of new broodstock can improve the genetic diversity.
Hybrid vigor has manifested to a certain extent in the present study.
Supported by the National “973” Program (G1999012008) and “863” Program (2002AA626020). 相似文献
3.
Traditional Ensemble Kalman Filter (EnKF) data assimilation requires computationally intensive Monte Carlo (MC) sampling, which suffers from filter inbreeding unless the number of simulations is large. Recently we proposed an alternative EnKF groundwater-data assimilation method that obviates the need for sampling and is free of inbreeding issues. In our new approach, theoretical ensemble moments are approximated directly by solving a system of corresponding stochastic groundwater flow equations. Like MC-based EnKF, our moment equations (ME) approach allows Bayesian updating of system states and parameters in real-time as new data become available. Here we compare the performances and accuracies of the two approaches on two-dimensional transient groundwater flow toward a well pumping water in a synthetic, randomly heterogeneous confined aquifer subject to prescribed head and flux boundary conditions. 相似文献
4.
Chinese and Japanese population of Chlamys farreri and their reciprocal hybrids were surveyed in isozyme variability at 13 loci by polyacrytamide gel electrophoresis (PAGE). Isozyme banding patterns indicated these hybrids were diploid. Loci that were observed as being monomorphic in inbred populations of C. farreri were also found to be monomorphic in filial progeny; loci that observed to be polymorphic in parental type generations were also polymorphic in hybrid generations. Differences existed among allelic frequency of the four types of cross. Within the reciprocal hybrids the expression of malic enzyme (ME) isozyme was sufficient to distinguishing individual hybrids because of the band, Rf=0.38. However, there were no noticeable variations among all the samples to differentiate one from another. Inbreeding was likely to be the main problem in aquaculture. The introduction of new broodstock can improve the genetic diversity. Hybrid vigor has manifested to a certain extent in the present study. 相似文献
5.
通过设计交配组合,建立中度近交组GM(近交系数大于0.25,家系G1,G2,G3,G4)、轻度近交组GL(近交系数0.0625—0.25,家系Z1,Z2,Z3,Z4),非近交组GN(近交系数为0,家系F1,F2,F3,F4),比较共同环境养殖90d不同近交程度凡纳滨对虾(Litopenaeus vannamei)家系体质量(BW)、存活率(SR)、高氨氮耐受存活率(SRA)及低溶氧耐受存活率间(SRH)的差异性,计算近交家系相关性状的近交衰退系数,评价近交对凡纳滨对虾生长、存活和抗逆性的影响。结果显示:GN组BW为7.66±2.86g,显著高于GM组BW(P0.05);GL组SR、SRA、SRH间差异近交衰退系数为–6.41%、–13.63%、–11.84%;GM组的SR、SRA、SRH的近交衰退系数为5.30%、–4.73%、–4.77%;Z2的BW最大为8.59±3.85g,G3的BW高于GN组均值;G2家系SR为84.81%±10.37%,显著高于其它家系(P0.05);75%的近交家系表现出SR近交衰退,62.5%的近交家系表现出SRH近交衰退。结果表明:近交导致凡纳滨对虾生长、高氨氮耐受性及低溶氧耐受性的衰退普遍存在,应避免高度近交个体的产生,近交系数应控制在0.25以下;少数近交家系的生长、存活、高氨氮耐受性或低溶氧耐受性优于非近交家系,推测选择合理亲缘选配方案可加快凡纳滨对虾遗传改良进程。 相似文献
6.
以2014年构建的壳金长牡蛎(Crassostrea gigas)全同胞家系为亲本,通过近交和设置对照组的方法,研究了近交对壳金长牡蛎家系幼虫期与稚贝期生长和存活的影响。结果表明,在整个实验期间,壳金F1家系的壳高、壳长和存活率均小于对照组。壳金F1家系的壳高和壳长仅在1日龄、190日龄与对照组差异不显著(P0.05),存活率仅在20日龄时与对照组差异显著(P0.05)。幼虫期,壳金F1家系壳高的近交衰退率范围为0.85%—13.70%,壳长的近交衰退率范围为0.75%—10.83%,存活率的近交衰退范围为4.24%—27.44%。稚贝期,壳金F1家系壳高的近交衰退率范围为6.16%—9.90%,壳长的近交衰退率范围为1.76%—14.21%,存活率的近交衰退范围为1.92%—4.18%。 相似文献
7.
Effects of effective population size on the F2 growth and survival of bay scallop Argopecten irradians irradians(Lamarck) 总被引：1，自引：0，他引：1
In 2002, six cohorts ofbroodstock bay scallop Argopecten irradians irradians （Ne=1, 2, 10, 30, 50 and control） were randomly chosen from a population of bay scallop to produce offspring. After one year rearing, with the progeny matured, the similar experiment was done to produce the F2 generation. To determine the magnitude of Ne effects, the growth and survival rates in larvae and adult of six F2 groups were compared. Results showed that inbreeding depression existed not only in the Ne=1 group but also in the Ne=2 group. The growth and survival rates of the two groups were significantly lower than those of the other groups （Ne=10, 30, 50, control）, and there were no significant differences among the latter （P〉0.05）. At the same time, the amount of depression in the Ne=1 group was significantly higher than that of the Ne=2 group （P〈0.05）. These results indicated that the low effective population size （Ne）, which increases the possibility of inbreeding, could lead to some harmful effects on the offspring. So it is essential to maintain a high level of Ne in commercial seed production. Fta＇thermore, as the high fecundity of bay scallop might lead to increased inbreeding, selecting broodstock from different growout sites is recommended. 相似文献
8.
The extinction of large carnivores in Europe during the Quaternary is reviewed and the potential role of glacial refugia in these extinctions is investigated using the VORTEX model for population viability analysis. A model was built for a medium sized big cat similar to the extinct Panthera gombaszoegensis utilising life history data from the modern jaguar Panthera onca. This approach highlighted the potential importance of glacial refugia in the extinction process. Even model refugia the size of the Italian peninsula did not guarantee persistence of a population over a 1000 yr time span, illustrating the role of chance in survival in such a refugium. An area the size of the largest Mediterranean island was unable to support a big cat population for a period of 1000 yr. The models also demonstrated the importance of inbreeding as a mechanism for extinction in refugia. It is suggested that repeated genetic bottlenecks during successive glaciations would tend to remove lethal recessive alleles from the population, increasing the probability of survival in refugia in subsequent glaciations. The history of extinction of large carnivores in the European Quaternary is interpreted in the light of these results. Copyright © 2002 John Wiley & Sons, Ltd. 相似文献
9.
牙鲆F1代近交系、雌核发育系的建立及遗传检测 总被引：2，自引：0，他引：2
在牙鲆育种中基于构建的大量家系,已经筛选出生长快成活率高的F1代家系0719,0750和0751,为了使其优良性状进一步纯化,采集以上3个优良家系中成熟个体的精子和卵子,分别利用家系内兄妹近交和鲈鱼冷冻精子诱导雌核发育的方式,构建了近交系3个、雌核发育系7个,在其生长至127 d和190 d时,测定体长和体重两个性状,并利用方差分析、Student-Newman-Keuls多重比较及绝对增重比较等法对两个性状进行分析,发现0751的雌核发育系较其他近交系和雌核发育系生长更快(P＜0.05)。利用倍性分析仪对0751近交系和雌核发育系的染色体倍性进行分析。结果显示近交系和雌核发育系分别在G0-G1期和G2-M期DNA 相对含量相近,G0-G1期DNA指数均为1.000,都具有二倍体的特点。利用筛选的14对具有多态性的微卫星引物分别对近交系和雌核发育系的遗传特征进行检测,发现近交系和雌核发育的等位基因数(Na)分别为2.214 3和2.000 0,有效等位基因数(Ne)分别为2.082 9和1.936 9,观测杂合度(Ho)分别为0.564 2和0.413 8(P＜0.05),期望杂合度(He)分别为0.515 4和0.490 1,遗传杂合度(Ave_Het)分别为0.506 6和0.482 8,多态信息含量(PIC)分别为0.403和0.366,雌核发育系的遗传指数均低于近交系。除EKOP-E1-In,EKOP17-Li,EKOP-E1-Ey 3个位点仅在近交系中为高度多态,其他位点在两个系中均为中度多态。近交系和雌核发育系的遗传偏离指数(d)分别为0.091 5和-0.157 3,反映了近交系杂合子的比例远高于理论上的数值,纯合子缺失;雌核发育系杂合子缺失,纯合子比例高。利用雌核发育较近交方式更有利于基因的纯合,在牙鲆育种中具有较大的应用价值。 相似文献
10.