Genetic similarities of 13 inbred lines of maize (Zea mays L.) were analyzed by restriction fragment length polymorphisms (RFLPs). The objectives of the study were to detect genetic similarities among 13 inbreds and t...Genetic similarities of 13 inbred lines of maize (Zea mays L.) were analyzed by restriction fragment length polymorphisms (RFLPs). The objectives of the study were to detect genetic similarities among 13 inbreds and to assign them to heterotic groups. By means of 24 probe_enzyme combinations (PECs) selected for locus specificity, clear patterns and reproducibility, 85 alleles were found with an average of 3.3 alleles per locus. The allelic frequency data were used to estimate genetic similarities among lines, and as a result the diversity index of 0.499 was obtained. Genetic similarities between the pairs of 13 lines ranged from 0.523 up to 0.802 with an average of 0.649. The UPGMA clustering algorithm analysis classified the 13 lines into five groups, which generally corresponded to known maize heterotic groups based on pedigree information. The authors concluded that RFLP_based markers could be used for investigating genetic relationships between maize inbred lines and assigning them to heterotic groups, but it seemed that a large number of PECs were needed to obtain reliable estimates of genetic similarity.展开更多
St 14(DXS 52)是人X染色体长臂远端的一段基因外DNA序列,与FVⅢ基因紧密连锁。我们分析了95个中国人的St 14/Taq I RFLPs,在44条无遗传关系的X染色体中,St14/Taq 13.6 kb片段出现的频率为31％而4.5kb、4.1kb片段出现的频率则相对较低,...St 14(DXS 52)是人X染色体长臂远端的一段基因外DNA序列,与FVⅢ基因紧密连锁。我们分析了95个中国人的St 14/Taq I RFLPs,在44条无遗传关系的X染色体中,St14/Taq 13.6 kb片段出现的频率为31％而4.5kb、4.1kb片段出现的频率则相对较低,与国外报道明显不同。以此RFLPs作为FVⅢ基因的遗传标志,我们分析了8个甲型血友病家系。3个家系中有缺陷FVⅢ基因的可以用此RFLPs进行连锁分析,其中1例为首次应用这一RFLPs连锁分析完成的产前基因诊断。展开更多
The polymorphisms(Pvu Ⅱand Hind Ⅲ) on the lipoprotein lipase(LPL) gene locus was investigated in a sample of 100 patients surviving previous myocardial infarction and 100 age matched healthy individuals selected fro...The polymorphisms(Pvu Ⅱand Hind Ⅲ) on the lipoprotein lipase(LPL) gene locus was investigated in a sample of 100 patients surviving previous myocardial infarction and 100 age matched healthy individuals selected from Han Chinese of Beijing area.In patient group a strong association was found between H+allele of Hind Ⅲ polymorphism and raised TG levels(P<0.01).In control group P-P-genotype was observed to be associated with higher TG levels compared with P+P genotype of Pvu Ⅱ polymorphism(P<0.05).Combination of H+H+ genotype with P-P-genotype showed the highest TG levels among all nine kinds of genotype combinations in patient group(P<0.01).However,comparison of distribution of alleles and genotypes of these polymorphisms between patient group and control group demonstrated no significant difference. Our data suggest that the polymorphisms at the LPL gene,as the linkage markers with an aetiologic mutation at or around LPL gene,may constitute one of the genetic determinants for the population variation in plasma TG levels,as well as for the common dyslipidemia in Chinese population.展开更多
Over the past several decades, especially through traditional breeding programme, intensive attempts have been made for the improvement of a large number of cereal varieties which adjusted to diverse agro-ecologies. H...Over the past several decades, especially through traditional breeding programme, intensive attempts have been made for the improvement of a large number of cereal varieties which adjusted to diverse agro-ecologies. However, increasing biotic and abiotic stresses, increasing populations, and sharply reducing natural resources especially water for agricultural purposes, push the breeders for organizing and developing improved cereal varieties with higher yield potential. In combination with developments in agricultural technology, plant breeding has made remarkable progress in increasing crop yields for over a century. Molecular markers are widely employed in plant breeding. DNA markers are being used for the acceleration of plant selection through marker-assisted selection (MAS). Genes of agronomic and scientific importance can be isolated especially on the basis of their position on the genetic map by using molecular markers technologies. In this review, the current status of marker development technologies for crop improvements will be discussed. It will also provide an outlook into the future approaches and most widely used applications in plant breeding in crop plants on the basis of present development.展开更多
文摘Genetic similarities of 13 inbred lines of maize (Zea mays L.) were analyzed by restriction fragment length polymorphisms (RFLPs). The objectives of the study were to detect genetic similarities among 13 inbreds and to assign them to heterotic groups. By means of 24 probe_enzyme combinations (PECs) selected for locus specificity, clear patterns and reproducibility, 85 alleles were found with an average of 3.3 alleles per locus. The allelic frequency data were used to estimate genetic similarities among lines, and as a result the diversity index of 0.499 was obtained. Genetic similarities between the pairs of 13 lines ranged from 0.523 up to 0.802 with an average of 0.649. The UPGMA clustering algorithm analysis classified the 13 lines into five groups, which generally corresponded to known maize heterotic groups based on pedigree information. The authors concluded that RFLP_based markers could be used for investigating genetic relationships between maize inbred lines and assigning them to heterotic groups, but it seemed that a large number of PECs were needed to obtain reliable estimates of genetic similarity.
文摘The polymorphisms(Pvu Ⅱand Hind Ⅲ) on the lipoprotein lipase(LPL) gene locus was investigated in a sample of 100 patients surviving previous myocardial infarction and 100 age matched healthy individuals selected from Han Chinese of Beijing area.In patient group a strong association was found between H+allele of Hind Ⅲ polymorphism and raised TG levels(P<0.01).In control group P-P-genotype was observed to be associated with higher TG levels compared with P+P genotype of Pvu Ⅱ polymorphism(P<0.05).Combination of H+H+ genotype with P-P-genotype showed the highest TG levels among all nine kinds of genotype combinations in patient group(P<0.01).However,comparison of distribution of alleles and genotypes of these polymorphisms between patient group and control group demonstrated no significant difference. Our data suggest that the polymorphisms at the LPL gene,as the linkage markers with an aetiologic mutation at or around LPL gene,may constitute one of the genetic determinants for the population variation in plasma TG levels,as well as for the common dyslipidemia in Chinese population.
文摘Over the past several decades, especially through traditional breeding programme, intensive attempts have been made for the improvement of a large number of cereal varieties which adjusted to diverse agro-ecologies. However, increasing biotic and abiotic stresses, increasing populations, and sharply reducing natural resources especially water for agricultural purposes, push the breeders for organizing and developing improved cereal varieties with higher yield potential. In combination with developments in agricultural technology, plant breeding has made remarkable progress in increasing crop yields for over a century. Molecular markers are widely employed in plant breeding. DNA markers are being used for the acceleration of plant selection through marker-assisted selection (MAS). Genes of agronomic and scientific importance can be isolated especially on the basis of their position on the genetic map by using molecular markers technologies. In this review, the current status of marker development technologies for crop improvements will be discussed. It will also provide an outlook into the future approaches and most widely used applications in plant breeding in crop plants on the basis of present development.
