| Artemia sinica is a bisexual artemia population unique to China, which belongsto the Arthopoda, Branchiata, Crustacea, Branchiopoda, Anostraca, Artemiidae,Artemia. As a kind of important aquaculture living bait and a model organism ofaquatic breeding, Study in breeding research and development in microsatellites isable to provide basic date for Artemia sinica and other crustaceans. This study mainlyfocuse on two questions: First is genetic parameter estimation, selection response anddegradation studies of Inbreeding pedigrees in the G3generation20-day old Artemiasinica; the second is the development and screening of microsatellite molecularmarkers.1. Use REML to estimate body length heritability and common environmentalfactor of20-day-old Artemia sinica, the result is: Body length heritability offast-growing strain in G3generation is0.50±0.074, while in slow-growing strain is0.31±0.14, which are all at high heritability level. The heritability in degradation: Forfast-growing strain is0.28±0.036, with common environmental factor0.11±0.015. Forslow-growing strain is0.21±0.074, with common environmental factor0.13±0.038,which are all at moderate heritability level. Combined date on survival rateheritability is: For fast-growing strain is0.34±0.051while slow-growing strain is0.43±0.060, all show high heritability level. Body length and survival rate heritabilityindicates that these two characters have a lot of room for improvement.2. Use the least-square mean estimation to analysis the selection response of thefast-growing and slow-growing strains. The body length least square mean of G1generation fast-growing family is10474.20μm, selection response is4.49%; G2generation is10226.52μm, selection response0.64%; G3generation is11090.97μm,selection response7.90%. For the slow-growing strain, G1generation is10095.21μm,selection response0.70%; G2generation is9616.85μm, selection response-5.36%;G3generation is10222.09μm, selection response-0.55%. selection response of thesetwo strains shows effective effect in breeding. 3. For inbreeding analysis, Four generations of inbreeding families were used asmaterials. The growth data were recorded，and the least squares mean were calculatedusing the general linear model. Three inbreeding levels of G2generation (F=0.0625，F=0.125，F=0.25) were designed. The least square mean of body length was9749.24μm,9298.87μm and9259.42μm, and reduced by4.23%,8.65%and9.04%,respectively, compared to10179.57μm of the control families. The body lengthshowed higher level of recession with the increase in the coefficient of inbreeding.For these3levels, increase of10%inbreeding coefficient lead to-6.77%,-6.92%and-3.62%inbreeding depression and-5.77%for comprehensive calculation. This resultshowed a significant recession of body length of Artemia sinica inbreeding families.Inbreeding coefficient of other selective breeding strains of G1,G2and G3generationare0,0and2.52%, including G3generation fast-growing strain of3.50%andslow-growing strain of0.10%, are at relatively low levels. Inbred had not yet impacton selective breeding.4. A SSR-enriched library was constructed using (GA)20and (CA)20as probes. Atotal of96positive clones were screened by colony hybridization, and142SSRs wereidentified from62clones. Primers were designed for45SSRs and all pairs of primerscould amplify fragments of the expected sizes. Among the45SSRs,16were detectedto be polymorphic.5. Screening from the NCBI database of all bisexual artemias, we had got5665sequences containing832microsatellites in all40609sequences (up to December2012). The number of di-nucleotide, tri-nucleotide, tetra-nucleotide, penta-nucleotideand hexa-nucleotide microsatellites was4244,1255,139,16and11. With Misa andPrimer3,109pairs of primers were designed and32of them were selected foroptimization and versatility detection. The result showed that only6pairs of primerscould amplify fragments of the expected sizes and the versatility was not very good. |
PDF Full Text Request