Forecast of the heterosis of Small Tail Han sheep crossed with imported meat sheep by genetic polymorphism of microsatellite DNA was done in different sheep breeds. The gene frequency, the polymorphism information con...Forecast of the heterosis of Small Tail Han sheep crossed with imported meat sheep by genetic polymorphism of microsatellite DNA was done in different sheep breeds. The gene frequency, the polymorphism information contents, the number of effective alleles, the heterozygosity, and the genetic distances were studied in four imported meat sheep and Small Tail Han sheep using five microsatellite loci. The crossing effects on the Small Tail Han sheep with four imported meat sheep were tested. The results indicate that there are genetic polymorphisms at five microsatellite loci in five sheep breeds. Five microsatellite loci can be used for genetic diversity evaluation in sheep breeds. The genetic variability of Dorset is the highest, and that of the Small Tail Han sheep is the lowest in the five sheep breeds. The order of heterosis from large to small in four imported meat sheep by the analysis of genetic relationship is White-Suffolk, Black-Suffolk, Dorset, and Texel. This accords with the testing results of actual heterosis. It is feasible to forecast the heterosis of Small Tail Han sheep crossed with imported meat sheep by genetic polymorphism of microsatellite DNA, which will have an important value for sheep breeding in the future.展开更多
The allelic frequency, the polymorphic information contents （PIC）, the number of effective alleles, the heterozygosity, and the genetic distances were studied in three imported meat sheep （Suffolk, Dorset, Texel） ...The allelic frequency, the polymorphic information contents （PIC）, the number of effective alleles, the heterozygosity, and the genetic distances were studied in three imported meat sheep （Suffolk, Dorset, Texel） and their F1 crossbred obtained from those crossed with indigenous Small Tail Hun Sheep （Suffolk♂× Small Tail Hun Sheep, SH; Dorset ♂× Small Tail Han Sheep♂, DH; Texel♂× Small Tail Hart Sheep ♀, TH） using six microsatellite DNA loci. The perpormences of three-breed crossbred （Suffolk ♂× DH ♀, Suffolk ♂× TH ♀, Texel ♂× SH ♀, Texel ♂× DH ♀, Dorset ♂× TH ♀, and Dorset ♂× SH ♀ ） were tested. The results indicated that there were genetic polymorphisms at six microsatellite loci in six sheep populations. Six microsatellite loci could be used for genetic diversity evaluation in sheep populations. The order of three-breed heterosis by the analysis of genetic relationship from large to small was Texel ♂× DH ♀, Suffolk ♂× DH ♀, Suffolki ♂× TH ♀, Texel ♂× SH ♀, Dorset ♂×TH ♀, and Dorset ♂× SH ♀, which was in accordance with the testing results on actual heterosis. These results showed that prediction of the best three-breed hybridized combination among sheep breeds by microsatellite DNA polymorphism was feasible, which will have an important value on the reasonable utilization of introduced meat sheep and sheep breeding in our country in the future.展开更多
Background： Sheep is important in the socio-economic lives of people around the world. It is estimated that more than half of our once common livestock breeds are now endangered. Since genetic characterization of Nig...Background： Sheep is important in the socio-economic lives of people around the world. It is estimated that more than half of our once common livestock breeds are now endangered. Since genetic characterization of Nigerian sheep is still lacking, we analyzed ten morphological traits on 402 animals and 15 microsatellite DNA markers in 384 animals of the 4 Nigerian sheep breeds to better understand genetic diversity for breeding management and germplasm conservation. Results： Morphological traits of Uda and Balami were significantly （P 〈 0.05） higher than Yankasa, which were both higher than West African Dwarf （WAD） sheep. Stepwise discriminant analysis showed tail length, rump height, chest girth, ear length and chest depth as the most discriminating variables for classification. Mahalanobis distances show the least differentiation between Uda and Balami and the largest between WAD and Balami sheep. While 93.3% of WAD sheep were correctly assigned to their source genetic group, 63.9% of Yankasa, 61.2% of Balami and 45.2% of Uda were classified correctly by nearest neighbour discriminant analysis. The overall high Polymorphism Information Content （PIC） of all microsatellite markers ranged from 0.751 to 0.927 supporting their use in genetic characterization. Expected heterozygosity was high for all loci （0.783 to 0.93）. Mean heterozygote deficiency across all populations （0.17] to 0.534） possibly indicate significant inbreeding （P 〈 0.05）. Mean values for FST, FIT and F^s statistics across all loci were 0.088, 0.394 and 0.336 respectively. Yankasa and Balami are the most closely related breeds （DA = 0.184） while WAD and Balami are the farthest apart breeds （DA-- 0.665）, which is coincident with distance based on morphological analysis and population structure assessed by STRUCTURE. Conclusions： These results suggest that within-breed genetic variation in Nigerian sheep is higher than between-breeds and may be a valuable tool for genetic improvement and conservation. The higher genetic variability in Yankasa suggests the presence of unique ancestral alleles reflecting the presence of certain functional genes which may result in better adaptability in characteristics are potentially useful in planning indigenous sheep. more agro-ecological zones of Nigeria. These genetic mprovement and conservation strategies in Nigerian展开更多
[Objective] This study aimed to investigate the genetic diversity of Macheng black goat and its correlation with heterosis.[Method] Ten microsatellite markers were selected for polymorphism investigation and statistic...[Objective] This study aimed to investigate the genetic diversity of Macheng black goat and its correlation with heterosis.[Method] Ten microsatellite markers were selected for polymorphism investigation and statistical analysis of Boer goat and Macheng black goat populations.[Result] The results showed that totally 175 alleles were found in 10 microsatellite loci; to be specific,the maximum number of detected alleles was 23,and the minimum number was 10; the effective number of alleles （Ne） was 6.4-18.1,with absolute difference value of 1.6-8.1 from the observed number of alleles.The highest gene frequency was 0.239 1 and the lowest was 0.002 7.The polymorphic information contents of all the ten microsatellite markers were above 0.95.The observed heterozygosity （Ho） ranged from 0.616 7 to 0.984 4 and the expected heterozygosity （He） ranged from 0.844 1 to 0.944 6.The average expected heterozygosity of Boer goat and Macheng black goat was respectively 0.894 0 and 0.906 7.Various body weight and body size indices of Boer goatxMacheng black goat hybrids were improved in varying degrees compared with Macheng black goat （with an increase range of 0.32％-30.06％）.The average heterosis rates of body height and chest girth were relatively high,while average heterosis rate of body weight was relatively low.[Conclusion] The genetic distance between Boer goat and Macheng black goat was 0.379 5,which is consistent with the geographical distribution of Boer goat and Macheng black goat populations and is fully relevant to the heterosis of Boer goat × Macheng black goat hybrids,indicating that investigating polymorphism via microsatellite loci is one of the feasible means to predict and analyze heterosis between varieties.展开更多
In the present study we studied the genetic structure of five Chinese sheep populations of Hu sheep, Tong sheep, Small-tailed Han sheep, Tan sheep, and Wadi （WD） sheep using 15 microsatellite loci. The results showe...In the present study we studied the genetic structure of five Chinese sheep populations of Hu sheep, Tong sheep, Small-tailed Han sheep, Tan sheep, and Wadi （WD） sheep using 15 microsatellite loci. The results showed that the FIT, FST, and FIS statistics computed for the complete dataset had the following values, 0.523±0.140, 0.363±0.131 and 0.263±0.092, respectively. All loci were significantly contributed to the genetic differentiation among population （P0.001）. There is no relationship between the scatter of pairwise FST geographical distance points as geographical distance increases between the five populations. Membership probabilities and genetic structure of sheep populations were estimated when K=2, the populations were classified into Hu, Tong, Han and WD, and Tan sheep group. However, when K=3, the populations were classified into Hu and Tong, Han and WD, and Tan sheep group. The findings supported the previous literatures that these populations are originated on different time stages from the primogenitor population and communicated genetically with each other by natural and artificial selection in different ecological environment.展开更多
文摘Forecast of the heterosis of Small Tail Han sheep crossed with imported meat sheep by genetic polymorphism of microsatellite DNA was done in different sheep breeds. The gene frequency, the polymorphism information contents, the number of effective alleles, the heterozygosity, and the genetic distances were studied in four imported meat sheep and Small Tail Han sheep using five microsatellite loci. The crossing effects on the Small Tail Han sheep with four imported meat sheep were tested. The results indicate that there are genetic polymorphisms at five microsatellite loci in five sheep breeds. Five microsatellite loci can be used for genetic diversity evaluation in sheep breeds. The genetic variability of Dorset is the highest, and that of the Small Tail Han sheep is the lowest in the five sheep breeds. The order of heterosis from large to small in four imported meat sheep by the analysis of genetic relationship is White-Suffolk, Black-Suffolk, Dorset, and Texel. This accords with the testing results of actual heterosis. It is feasible to forecast the heterosis of Small Tail Han sheep crossed with imported meat sheep by genetic polymorphism of microsatellite DNA, which will have an important value for sheep breeding in the future.
基金supported by the Key Project of Ministry of Science and Technology of China(2008BADB2B04-9)the Key Project of Hebei Province,China(07220401D-2)
文摘The allelic frequency, the polymorphic information contents （PIC）, the number of effective alleles, the heterozygosity, and the genetic distances were studied in three imported meat sheep （Suffolk, Dorset, Texel） and their F1 crossbred obtained from those crossed with indigenous Small Tail Hun Sheep （Suffolk♂× Small Tail Hun Sheep, SH; Dorset ♂× Small Tail Han Sheep♂, DH; Texel♂× Small Tail Hart Sheep ♀, TH） using six microsatellite DNA loci. The perpormences of three-breed crossbred （Suffolk ♂× DH ♀, Suffolk ♂× TH ♀, Texel ♂× SH ♀, Texel ♂× DH ♀, Dorset ♂× TH ♀, and Dorset ♂× SH ♀ ） were tested. The results indicated that there were genetic polymorphisms at six microsatellite loci in six sheep populations. Six microsatellite loci could be used for genetic diversity evaluation in sheep populations. The order of three-breed heterosis by the analysis of genetic relationship from large to small was Texel ♂× DH ♀, Suffolk ♂× DH ♀, Suffolki ♂× TH ♀, Texel ♂× SH ♀, Dorset ♂×TH ♀, and Dorset ♂× SH ♀, which was in accordance with the testing results on actual heterosis. These results showed that prediction of the best three-breed hybridized combination among sheep breeds by microsatellite DNA polymorphism was feasible, which will have an important value on the reasonable utilization of introduced meat sheep and sheep breeding in our country in the future.
基金supported by the College of Agriculture and Life Sciences,Cornell University, Ithaca, NY. USAsupport from the United States Agency for International Development (USAID) through the award of the Norman Borlaug Leadership Enhancement in Agriculture Program (LEAP)Fellowship to Moses Okpekuresearch grant from International Foundation for Science, Stockholm to Moses Okpeku
文摘Background： Sheep is important in the socio-economic lives of people around the world. It is estimated that more than half of our once common livestock breeds are now endangered. Since genetic characterization of Nigerian sheep is still lacking, we analyzed ten morphological traits on 402 animals and 15 microsatellite DNA markers in 384 animals of the 4 Nigerian sheep breeds to better understand genetic diversity for breeding management and germplasm conservation. Results： Morphological traits of Uda and Balami were significantly （P 〈 0.05） higher than Yankasa, which were both higher than West African Dwarf （WAD） sheep. Stepwise discriminant analysis showed tail length, rump height, chest girth, ear length and chest depth as the most discriminating variables for classification. Mahalanobis distances show the least differentiation between Uda and Balami and the largest between WAD and Balami sheep. While 93.3% of WAD sheep were correctly assigned to their source genetic group, 63.9% of Yankasa, 61.2% of Balami and 45.2% of Uda were classified correctly by nearest neighbour discriminant analysis. The overall high Polymorphism Information Content （PIC） of all microsatellite markers ranged from 0.751 to 0.927 supporting their use in genetic characterization. Expected heterozygosity was high for all loci （0.783 to 0.93）. Mean heterozygote deficiency across all populations （0.17] to 0.534） possibly indicate significant inbreeding （P 〈 0.05）. Mean values for FST, FIT and F^s statistics across all loci were 0.088, 0.394 and 0.336 respectively. Yankasa and Balami are the most closely related breeds （DA = 0.184） while WAD and Balami are the farthest apart breeds （DA-- 0.665）, which is coincident with distance based on morphological analysis and population structure assessed by STRUCTURE. Conclusions： These results suggest that within-breed genetic variation in Nigerian sheep is higher than between-breeds and may be a valuable tool for genetic improvement and conservation. The higher genetic variability in Yankasa suggests the presence of unique ancestral alleles reflecting the presence of certain functional genes which may result in better adaptability in characteristics are potentially useful in planning indigenous sheep. more agro-ecological zones of Nigeria. These genetic mprovement and conservation strategies in Nigerian
文摘[Objective] This study aimed to investigate the genetic diversity of Macheng black goat and its correlation with heterosis.[Method] Ten microsatellite markers were selected for polymorphism investigation and statistical analysis of Boer goat and Macheng black goat populations.[Result] The results showed that totally 175 alleles were found in 10 microsatellite loci; to be specific,the maximum number of detected alleles was 23,and the minimum number was 10; the effective number of alleles （Ne） was 6.4-18.1,with absolute difference value of 1.6-8.1 from the observed number of alleles.The highest gene frequency was 0.239 1 and the lowest was 0.002 7.The polymorphic information contents of all the ten microsatellite markers were above 0.95.The observed heterozygosity （Ho） ranged from 0.616 7 to 0.984 4 and the expected heterozygosity （He） ranged from 0.844 1 to 0.944 6.The average expected heterozygosity of Boer goat and Macheng black goat was respectively 0.894 0 and 0.906 7.Various body weight and body size indices of Boer goatxMacheng black goat hybrids were improved in varying degrees compared with Macheng black goat （with an increase range of 0.32％-30.06％）.The average heterosis rates of body height and chest girth were relatively high,while average heterosis rate of body weight was relatively low.[Conclusion] The genetic distance between Boer goat and Macheng black goat was 0.379 5,which is consistent with the geographical distribution of Boer goat and Macheng black goat populations and is fully relevant to the heterosis of Boer goat × Macheng black goat hybrids,indicating that investigating polymorphism via microsatellite loci is one of the feasible means to predict and analyze heterosis between varieties.
基金supported by the earmarked fund for China Agriculture Research System (CARS-39)the International Cooperation Item of the National Natural Science Foundation of China (30410103150)+7 种基金the China Postdoctoral Science Foundation Special Funded Project (200902154)the China Postdoctoral Science Foundation (20080430470)the Key Technologies R&D Program of China during the 11th Five-Year Plan period (2006BAD13B08-07)the Natural Science Foundation of Jiangsu Province of China (BK2007556)the Basic Natural Science Foundation for Colleges and Universities, Jiangsu Province of China (NK051039)the Northern Jiangsu Technology Development Plan of China (BN2010004)the Science and Technology Program of Suzhou City of Jiangsu Province of China (SNG0911)the Jiangsu Government Scholarship for Overseas Studies Project, China
文摘In the present study we studied the genetic structure of five Chinese sheep populations of Hu sheep, Tong sheep, Small-tailed Han sheep, Tan sheep, and Wadi （WD） sheep using 15 microsatellite loci. The results showed that the FIT, FST, and FIS statistics computed for the complete dataset had the following values, 0.523±0.140, 0.363±0.131 and 0.263±0.092, respectively. All loci were significantly contributed to the genetic differentiation among population （P0.001）. There is no relationship between the scatter of pairwise FST geographical distance points as geographical distance increases between the five populations. Membership probabilities and genetic structure of sheep populations were estimated when K=2, the populations were classified into Hu, Tong, Han and WD, and Tan sheep group. However, when K=3, the populations were classified into Hu and Tong, Han and WD, and Tan sheep group. The findings supported the previous literatures that these populations are originated on different time stages from the primogenitor population and communicated genetically with each other by natural and artificial selection in different ecological environment.
