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1.
For the first generation of a selective breeding programme, it is important to minimize the possibility of inbreeding. This mostly occurs by mating between closely related individuals, while proper mating can provide an opportunity to establish the base families with wide genetic variation from which selection for subsequent generations can be more effective. Genotyping with microsatellite‐based DNA markers can help us determine the genetic distances between the base populations. The genetic markers further facilitate the identification of the correct parents of the offspring (parentage assignments) reared together with many other families after hatching. We established a genetic analysis system with microsatellite DNA markers and analysed the genetic distances of three farmed stocks and a group of fish collected from wild populations using eight microsatellite markers. The averaged heterozygosity of the farming stocks was 0.826 and that of the wild population was 0.868. The hatchery strains had an average of 8.6 alleles per marker, which was less than a wild population that carried an average of 14.3 alleles per marker. Significant Hardy–Weinberg disequilibrium (HWDE) was observed in two farming stocks (P<0.05). Despite relatively low inbreeding coefficiency of the hatchery populations, the frequency of a few alleles was highly represented over others. It suggests that the hatchery stocks to some extent have experienced inbreeding or they originated from closely related individuals. We will develop a selective program using the DNA markers and will widen the usage of the DNA‐based genetic analysis system to other fish species.  相似文献   

2.
The Apostichopus japonicus is a valuable aquaculture species in China. In this study, 51 single nucleotide polymorphisms (SNPs) were identified from expressed sequence tags of sea cucumber using high‐resolution melting. The average observed heterozygosity (Ho) and expected heterozygosity (He) were 0.2462 and 0.2897, respectively. Thirty‐two of these loci were used for estimating the genetic similarity and variation between the five hatchery stocks from China and two wild stocks from Japan. No significant differences in Ho or He were observed between the wild and hatchery populations. The pairwise Fst (which ranged from 0.0119 to 0.0236) and the genetic identity (which varied from 0.9802 to 0.9915) showed no significant differentiation between the wild and cultured stocks. The analysis of molecular variance indicated the source of variation was at the level of “within the populations.” The information on the genetic variation and differentiation in cultured and wild populations of A. japonicus obtained in this study is useful for setting up suitable guidelines for founding and maintaining of cultured stocks and for future genetic improvement by selective breeding.  相似文献   

3.
The loss of variability in farmed populations and the risks of interactions with wild populations support the need for the genetic monitoring of species farmed throughout the world. In Brazil, the tambaqui is the most widely farmed native fish species. Despite this, there are no data on the pedigree of the farmed stocks, and the potential for interactions with wild populations in the Amazon basin has raised concerns with regard to the genetic variability of these stocks. The present study analysed sequences of the mitochondrial Control Region and 12 microsatellites to characterize the genetic variability of seven historically important commercial tambaqui breeding centres located in four different regions of Brazil, and compared these sequences with those obtained from individuals collected from a wild population. High levels of genetic diversity were found in the wild population, whereas genetic diversity was reduced in both markers in most captive populations, except for the broodstock located near the Amazon River. High FST and DEST indices were recorded between the wild population and most of the captive stocks analysed. The drastic reduction in genetic diversity found in most captive stocks and the difference between these stocks and the wild population may have been the result of the small size of the founding populations and the absence of breeding management. The renewal of the broodstocks and the application of breeding management techniques are recommended. In the Amazon region, in addition, the use of broodstocks that are genetically very different from local wild populations should be avoided.  相似文献   

4.
The microsatellite DNA technique was used to detect the genetic variations between wild and cultured populations of Kuruma prawn Marsupenaeus japonicus Bate 1888. All the six microsatellite loci screened in this study showed high polymorphism for their PIC (0.6701–0.8989), which was much more than the standard value of 0.5. A total of 73 alleles were observed over six loci from 93 shrimps. The mean number of allele locus ranged from 9.83 (cultured) to 11.83 (wild). The number of effective alleles varied from 6.86 (cultured) to 8.58 (wild). The average of observed heterozygosity (Ho) of populations varied from 0.6935 (cultured) to 0.7370 (wild), and that of expected heterozygosity (He) was 0.8169 (wild) and 0.8209 (cultured). Tests of Hardy–Weinberg showed that these loci deviated significantly or highly significantly in one or both populations. Compared with the wild population, the cultured population showed little reduction in genetic variation. The total number of alleles (71, 59) was not significantly (P=0.296) different between wild and cultured populations. The paired‐samples t test of observed heterozygosity and expected heterozygosity implied that there was no significant difference (P=0.572 and 0.891 respectively) between wild and cultured populations. However, some rare allele loss might have occurred in the cultured population. A total of 14 unique alleles were found in the wild population, but only two unique alleles were observed in the cultured population. Therefore, there is a need to monitor genetic variability of cultured population, and to improve the hatchery program for the conservation of wild Kuruma prawn resources.  相似文献   

5.
Farming of the sea cucumber Apostichopus japonicus (Selenka) started 20 years ago and is still in rapid expansion in China. In order to assess the genetic status of both wild and cultivated stocks of this species, we used eight microsatellite markers to estimate the level of genetic diversity within five hatchery stocks and two wild populations of A. japonicus, and compared the degree of genetic differentiation between them. High levels of polymorphism were observed over all loci. The mean alleles and expected heterozygosities over the seven stocks were 10.4–12.3 and 0.735–0.783 respectively. The results of the microsatellite survey provide no evidence to show that hatchery practice of the sea cucumber in China to date has significantly affected the genetic variability of the cultured stocks. Significant differentiation was found between most pairs of the hatchery stocks and wild populations (Fst range: 0.008–0.036), and no obvious difference was detected between the wild populations (Fst=0.008). The information on the genetic variation and differentiation obtained in this study can be applied for future genetic monitoring of A. japonicus aquaculture stocks and will be useful for future genetic improvement by selective breeding, and for designing suitable management guidelines for these genetic materials.  相似文献   

6.
The escape or release of cultured and domesticated organisms into the wild poses a threat to the genetic integrity of natural populations. Based on data from 17 microsatellite loci, the genetic differentiation between wild and hatchery Oujiang color common carp Cyprinus carpio var. color was investigated, and its potential application for identifying the escapees of hatchery strains was assessed using Bayesian genetic assignment. No significant differences were observed between pooled hatchery and pooled wild populations in terms of allelic richness (A R), observed heterozygosity (H O), and inbreeding coefficient (F IS). Analysis of molecular variance and pairwise F ST comparisons suggested significant genetic differentiation between hatchery strains and between hatchery and wild populations, which was further confirmed by principal components analysis and Bayesian clustering analysis. Bayesian genetic alignment showed high self-assignment accuracy (ranging from 86.0 to 96.0%) in the original populations, demonstrating the ability of this technique to identify hatchery Oujiang color common carp escapees in the wild population.  相似文献   

7.
Nuclear insulin-like growth factor 2 gene (IGF-2), growth hormone 1 gene (GH-1) and internal transcribed spacer 1 (ITS-1) of the ribosomal DNA as well as the mitochondrial NADH-3 and NADH-4 dehydrogenase genes (ND-3/4) exhibited species-specific restriction fragment patterns and three microsatellite loci (Sfo18, Ssa85 and Ssa197) had non-overlapping allele size ranges in Arctic charr and brook trout and were used as diagnostic markers for testing genetic purity of hatchery stocks and wild populations of Arctic charr and brook trout in Bavaria, Germany. Screening of four wild populations (three in Arctic charr and one in brook trout) revealed only a single hybrid (back-cross to brook trout) individual in L. Starnberg. In contrast, in three (out of five) hatchery stocks of Arctic charr and in both hatchery stocks of brook trout hybrids were detected with the frequency from 3 to 100%. Three hatchery stocks (SS2, SA and BS1) represent a hybrid swarm because they contained a very high proportion of hybrids (from 83 to 100%) and most or all hybrid individuals had alien alleles at only one or a few of six unlinked diagnostic loci, indicating that post-F1 hybrids represent the majority of individuals in these stocks and introgression has taken place. Release or escape of introgressed individuals from hatcheries into natural water bodies should be avoided in order to protect the biological diversity and genetic integrity of native fish populations.  相似文献   

8.
Milkfish hatchery broodstock are either from on‐grown wild‐caught or hatchery‐produced fry/juveniles. To determine if a marker‐assisted management scheme can be formulated for improved milkfish hatchery production, milkfish stocks were genetically characterized using nine novel short tandem repeats or microsatellites. Eight wild‐bred Philippine stocks (CLA, CUR, CAM, SIH, SBH‐I1, HH, PAL and ZH‐P0), four hatchery‐bred stocks (SBH‐I2, SBH‐D, BoH and ZH‐F1), two farm stocks of known mixed lineages (SPH and BDH) and one Indonesian hatchery‐bred stock (WJH) were assessed. WJH was included since milkfish fingerlings from Indonesia reared in Philippine farms could be developed into future broodstock. Mean allelic richness (Ar) was highest in wild‐bred stocks (9.5) and lowest in hatchery‐bred spawners (9.1). Mean expected heterozygosities (He) were relatively similar in all stocks with wild‐bred stocks slightly higher (0.67) than the others. An analysis of molecular variance indicated significant yet low genetic differentiation among stocks (FST = 0.013; p = .000) where variation (98.6%) was explained by intra‐stock differences. In some of the domesticated stocks, reductions in mean allelic richness were observed in first generation hatchery broodstock (e.g. ZH‐F1; Ar = 8.3), compared with their founder stock (e.g. ZH‐P0; Ar = 9.4). The Indonesian stock was similar to local wild‐bred stocks based on genetic variability indices; thus, it might be likely that the local stocks’ fitness traits could be comparable with the imported milkfish stock which has been perceived to be better. The quality of locally available farmed milkfish and prospects of formulating a broodstock management scheme for the production of good quality milkfish seedstock are herewith discussed.  相似文献   

9.
Macrobrachium rosenbergii, known as the giant freshwater prawn or Malaysian prawn, is the sixth largest aquaculture species in Asia. Knowledge of genetic diversity of M. rosenbergii is important to support management and conservation programmes, which will subsequently help in sustainable production of this economically important species. This study aimed to analyse the genetic diversity and population structure of five M. rosenbergii populations using 11 microsatellite loci. In analysing 240 samples, the number of alleles, observed heterozygosity (HO) and expected heterozygosity (HE) ranged from 3 to 20, from 0.250 to 0.978 and from 0.556 to 0.944 respectively. The five stocks of M. rosenbergii displayed high level of genetic diversity. Both the FST and amova analyses showed that there was significant genetic differentiation among all populations. The UPGMA dendrogram based on Nei's genetic distance matrix revealed that the Narmada and Mahi populations were in one cluster and Mahanadi and Subarnarekha populations in another single major branch, whereas the Kerala population clearly showed a separate cluster. This information on genetic variation will be useful for genetic improvement and conservation of Indian populations of giant freshwater prawn M. rosenbergii.  相似文献   

10.
Rainbow trout, Oncorhynchus mykiss (Walbaum), were first introduced into Australia over 100 years ago, and forms the basis of important recreational inland fisheries and an aquaculture industry in south‐eastern Australia. This paper investigates the genetic variation within and between samples of Australian rainbow trout using allozyme electrophoresis. The levels of genetic diversity within Australia do not show marked differences from those observed in hatchery and wild populations from throughout North America, New Zealand and South Africa, but there is evidence for the loss of some rare alleles during translocation from California to Australia via New Zealand. No appreciable difference in genetic diversity was apparent between hatchery and self‐sustaining wild populations of rainbow trout from mainland Australia. However, significant differences in allelic frequencies were observed, with consistent genetic differences between Victorian and New South Wales samples most likely reflecting state‐based hatchery and stocking policies.  相似文献   

11.
After more than 20 years of hatchery production of Asian seabass in Thailand, genetic information is still lacking for effective genetic management and a selective breeding programme. This study aimed to evaluate genetic status of existing hatchery populations and genetic consequences of a selective breeding attempt. We examined genetic relatedness in seven hatchery samples, including a selectively bred population (RACF‐F1), compared with three wild samples using 11 microsatellite loci. Genetic diversity and relatedness values within most hatchery samples, except for RACF‐F1, did not differ from those of wild populations (P > 0.05). RACF‐F1 had the lowest allelic diversity and effective population size (Ar = 6.99; Ne = 7.8) and highest relatedness values (mean rxy = 0.075–0.204). Pairwise ΦST values, principal component analysis and model‐based cluster analyses revealed three genetically distinct hatchery groups: Eastern Thailand (CHN, RACF, NSCF and SKCF), Southern Thailand (NICA) and the Andaman Sea (STCF). Results suggest that exiting domestic populations capture reasonable amount of genetic variation and can be useful for a base population for genetic improvement programmes. In addition, given the rapid increase in relatedness that we observed in one selectively bred population, we recommend using selection methods and hatchery practices that reduce variability in family contribution in the subsequent generations.  相似文献   

12.
Abstract Stocking has had a considerable effect on wild brown trout, Salmo trutta L., populations throughout Europe. To elucidate this impact and to outline further management strategies, the genetic structure of 25 wild populations and five hatchery stocks from Czech Republic and Slovakia were analysed using mitochondrial (control region) and nuclear DNA (microsatellites, LDH‐C1*) markers. Stocking practices have caused massive hybridisation between the Atlantic and Danube brown trout strains in the central Danube basin and have lead to a loss of among‐population divergence in Slovakia and the eastern part of Czech Republic. Comparison with studies from neighbouring countries revealed substantial differences in haplotype, allele frequencies and genetic diversity across Central Europe. Differences in stocking management and origin of breeding stocks appear to be crucial factors for the spatial variability of the genetic structure of brown trout.  相似文献   

13.
Genetic diversity between three farmed and four wild populations of Atlantic salmon from Ireland and Norway were analysed using 15 microsatellite markers. High levels of polymorphism were observed over all populations with the average number of alleles and average heterozygosity at 17.8 and 0.70, respectively. Farmed salmon showed less genetic variability than wild salmon in terms of allelic diversity but not necessarily in terms of overall heterozygosity. Between farmed populations significant differences were observed in expected heterozygosity suggesting that more intensive breeding practices may have resulted in a further erosion of genetic variability. Phylogenetic analysis using either populations or individuals as nodes show a clustering of populations into two groups, farmed and wild. This suggests that founder effects and subsequent selection have had more effect on the genetic differentiation between these strains than geographical separation. This technology has great potential for use in aquaculture situation where levels of genetic variation could be monitored and inbreeding controlled in a commercial breeding progra.  相似文献   

14.
Aquaculture of barramundi or Asian seabass (Lates calcarifer) is growing in both Australia and Southeast Asia and there is substantial interest to improve production efficiency through selective breeding. The establishment of a large and genetically diverse base population is a prerequisite for a sustainable and long‐term productive breeding program. Before selective breeding programs can begin for Australian barramundi it is important to assess the overall genetic diversity of current captive broodstock populations. To address this question, 407 captive barramundi broodstock from eight separate Australian broodstock populations were genotyped using 16 polymorphic microsatellite DNA markers. A Bayesian STRUCTURE analysis indicated that captive Australian broodstock are broadly divided into two genetic stocks. Multivariate analysis between broodstock individuals and pairwise FST between broodstock populations also supported the existence of two stocks. Comparisons with data obtained from natural stocks suggested that hatchery individuals were either sourced from the two stocks or represented an admixture between them. Genetic diversity was low within each broodstock population (allelic richness ranged from 2.67 to 3.42 and heterozygosity ranged from 0.453 to 0.537) and relatedness estimates within hatcheries were generally low (average r was equal to 0.141). We recommend sourcing captive individuals according to high levels of neutral genetic diversity and low levels of relatedness for the establishment of a base population. We also make recommendations about including genetically diverse wild individuals.  相似文献   

15.
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16.
To determine the potential for productive efficiency and genetic improvement in the clam (Meretrix meretrix), four populations were produced from a diallel mating of two different geographical stocks (SD and JS). The genetic parameters at nine novel microsatellite loci indicated that the numbers of alleles, observed heterozygosity and polymorphic information content of the reciprocal cross populations (SDJS and JSSD) were larger than those of the pure populations (JSJS and SDSD). The values of Nei's unbiased genetic distance and FST revealed that the largest genetic divergence was between the two pure populations (DC=0.2993, FST=0.1438) and the smallest was between the two reciprocal cross populations (DC=0.1093, FST=0.0583). In addition, the mean shell lengths of the reciprocal cross populations were significantly larger than that of the pure populations by 1.577 mm (P<0.05), and the same trend was observed in the other traits. A significant maternal effect was revealed after analysis of the effects of egg origin and mating strategy on the four traits. Heteroses for all the traits were detected in the reciprocal cross populations. Our research implies an extensive development potential in productive efficiency and genetic improvement for M. meretrix.  相似文献   

17.
《水生生物资源》2003,16(6):501-508
The Latin American shrimp Litopenaeus stylirostris was introduced in three different Pacific islands (Tahiti, New Caledonia via Tahiti, and Hawaii) and hatchery-propagated for 7–25 generations to develop shrimp farming based on these domesticated stocks. Three microsatellite markers have been used in an attempt to assess the genetic bases of the populations available to start a selective breeding program. The comparison of eight hatchery stocks (five New Caledonian, two Hawaiian and one Tahitian stocks) and one wild Ecuadorian population showed a much lower variability in the domesticated stocks than in the wild population, especially in New Caledonia and Tahiti (2–3.7 vs. 14–27 alleles per locus; 20–60% vs. 90% expected heterozygosity). The Tahitian and the New Caledonian stocks share the same alleles, suggesting that the loss of alleles occurred during the common past of these populations. On the contrary, New Caledonian and Hawaiian populations share only one common allele at the three loci studied. Although the low genetic variability and the resulting inbreeding of the New Caledonian stocks do not seem to affect their present performance, the results of this study demonstrate the usefulness of the introduction of new stocks in order to increase the potential responses to new controlled or uncontrolled selective pressures. The introduction in New Caledonia of the Hawaiian domesticated stocks, which would provide the local shrimp industry with 40% of the allelic diversity of the species, is advised and preferred to the one of wild animals in order to take advantage (i) of the spontaneous selection which occurred during domestication and (ii) of their favourable sanitary “specific pathogen free” status (no presence of four viruses: WSV, YHV, IHHNV, TSV) which limits the risk of introduction of pathogens.  相似文献   

18.
Trace elements in otoliths of sea bass (Dicentrarchus labrax L.) and sea bream (Sparus aurata L.) from fish farms and coastal wild populations in the western Mediterranean Sea were analysed by inductively coupled plasma-mass spectrometry. Results showed that concentrations of Mg, K, and Mn differed significantly between wild and farmed sea bass, while concentrations of Mg, K, Mn, Fe, Zn, Sr, and Ba varied significantly between wild and farmed sea bream. Discriminate analysis and cross-validation classification showed that the trace element profile in otoliths can be used to separate farmed fish from wild stocks with high accuracy on both sea bass (individuals correctly classified: 90.7 %) and sea bream (individuals correctly classified: 96.6 %). Moreover, trace elements in otoliths resulted to be useful to discriminate among wild fish stocks within each species.  相似文献   

19.
Salmo trutta abanticus is a non‐anadromous trout species native to Lake Abant and Seven Lakes in Turkey. A restocking programme by captive breeding was initiated in 1999 to support S. trutta abanticus population. Reared 2‐year‐old juveniles from randomly caught wild parental individuals in Maçka breeding farm were introduced into Lake Abant. We aimed to compare genetic and morphological divergences between wild‐ and captive‐bred populations using seven microsatellite loci and geometric morphometric measurements. A significant genetic and morphological divergences were detected between all population in Fst and canonical variate analysis based on geometric morphometric with 10 homolog landmark. Eighty‐six microsatellites alleles were recorded across loci. Number of private alleles, observed alleles and observed heterozygosity are statistically significant higher in Maçka captive‐bred population than Lake Abant and Seven Lakes populations. Of 42 tests, three departures from Hardy–Weinberg equilibrium were detected in all populations after Bonferroni correction. Two pairs of loci (Ssa85 – Str73 and Str73‐Str543) in Maçka, one pairs of loci (Ssa85‐Str73) in Abant and two pairs of loci (Ssa85‐Str60 and Str73‐Str543) in Seven Lakes populations show linkage disequilibrium. Population structure analysed with Structure software showed three genetic groups (?K = 3) in our studied populations. Relatedness estimates show higher mean relatedness values (r = 0.220 ± 0.230) for Maçka captive‐breed population than wild populations of Abant Lake and Seven Lakes (r = 0.140 ± 0.210 and r = 0.170 ± 0.200 respectively).  相似文献   

20.
Supportive breeding of Atlantic salmon (Salmo salar) is commonly employed to maintain numbers of fish where the species has become locally endangered. Increasingly, one of the main aims of population management is the preservation of natural genetic diversity. If the stocks employed in supportive breeding exhibit reduced variation they can alter the natural pattern of genetic variation observed in wild populations. In northern Spain, wild adult salmon are caught every year from local rivers and artificially crossed in order to create supportive stocks. The offspring are hatchery reared until the juvenile stage, then released into the same river where their parents were caught. In the current study, our findings demonstrate that although adult broodstock exhibit a pattern of variation similar to the wild populations, variability at microsatellite loci was drastically reduced in the juveniles released into one of three rivers analyzed. The contribution of broodstock to this juvenile stock was examined by pedigree analysis. A restricted number of females contributing to the hatchery stock was identified as the main cause of loss in genetic variation, possibly due to overmaturity of some multi-sea-winter females. We suggest that better monitoring and control of parental contribution will help in solving the problem of loss of genetic diversity in hatchery populations.  相似文献   

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