滇中稻瘟病菌多样性及分布

对采自云南水稻主产区 15县的 2 36个稻瘟病菌株进行了rep -PCR (repetitiveelement basedpolymerasechainre action)指纹分析 ,应用STATISTICA 5 0软件UPGRAM程序构建了 134个代表菌株的DNA指纹聚类图。依 1 75遗传相似距将供试菌株划分为 8个遗传型群 ,第 1,2 ,4群为优势群。各遗传型群具有一定的地域性 ,同一块稻田同一寄主品种上稻瘟病菌遗传型群基本一致 ,但有时包含不同的遗传型 ,甚至同一病斑存在遗传型差异。

Genetic structure of wintering Hooded Cranes (Grus monacha) based on mitochondrial DNA D-loop sequences

The Hooded Crane (Grus monacha) is a waterbird wintering in the wetlands of the middle and lower reaches of the Yangtze River, China. The gradual habitat loss resulting from wetland degradation may have posed negative effects on the structure of our wintering populations. For its effective protection, it is important to conduct an intensive study on the genetic structure of this population. A total of 221 faecal samples, nine feather samples and four muscle samples of Hooded Cranes from four wintering populations, i.e., from Caizi Lake and Shengjin Lake in Anhui, Poyang Lake in Jiangxi and Chongming Dongtan in Shanghai, were collected for this study. Full-length 1103–1104 bp mtDNA D-loop sequences from 72 samples were amplified using PCR. Based on our amplified D-loop sequences and the sequences of two individual birds obtained from GenBank (AB017625 and AB023813), we analyzed the genetic structure of these four wintering Hooded Crane populations. Twenty six variable sites were found among 72 target sequences in the four wintering populations and 23 haplotypes were defined. Genetic diversity analyses showed that the haplotype diversity of Hooded Cranes was 0.823 ± 0.042 with a nucleotide diversity of 0.00157 ± 0.00021. The FST values of the four populations show that there is no significant genetic differentiation among the populations of Hooded Cranes wintering in the middle and lower reaches of the Yangtze River. Tajima’s D and Fu’s tests suggest that the Hooded Crane populations may have experienced population expansion in their evolutionary history.

Genetic Variation and Differentiation of Larix decidua Populations in Swiss Alps

Genetic diversity within and among six subpopulations of Larix decidua Mill. from two altitudinal transects of Swiss Alps was investigated using 6 enzyme systems coding for 8 loci. Globally, the mean proportion of polymorphic loci was 22.9%, the average number of alleles per locus was 1.3, and the mean expected heterozygosity was 0.095. Only 5.8% of the genetic variation resided among populations. The mean genetic distance was 0.006. Several significant differences of gene frequencies were found between different age classes. Positive values of the species mean fixation index observed in this study suggested a considerable deficit of heterozygotes in the populations of L. decidua of Swiss Alps. At one of the sites (Arpette), the highest subpopulation in elevation gave the lowest level of genetic diversity (as evidenced by the lowest proportion of polymorphic loci and the lowest mean expected heterozygosity) and the largest value of genetic distance when compared to other subpopulations. The genetic differences between the highest subpopulation and the other ones suggest that the founder effect may be an important factor influencing genetic differentiation of L. decidua populations at Arpette transect.

Characteristics of dental morphology in the Xinjiang Uyghurs and correlation with the EDARV370A variant

Teeth are one of the most important materials for anthropological studies because they are likely to be preserved in ancient remains.While the frequencies of dental characteristics can provide clues to the phylogeny of populations,genetic studies at the individual level can further reveal the biological mechanisms and evolutionary context of dental characteristics.In this study,by analyzing 38 dental characteristics of 242 Xinjiang Uyghur individuals,we found that(i)the dental characteristics of the Uyghurs showed evidence of admixture between European and East Asian populations.The admixture proportions were in line with those previously reported in population genetic studies;(ii)the Xinjiang Uyghur dental characteristics formed three clusters in pairwise correlation analysis.One of the main clusters consisted of characteristics including incisor shoveling,double shoveling and mesial ridge;and(iii)all the characteristics in this cluster were significantly correlated with the genetic variant EDARV370A.The extracted composite phenotypic factor was also significantly associated with EDARV370A,which explained 18%of the total phenotypic variance.This indicated a pleiotropic effect,i.e.,the same genetic factor affects a number of dental characteristics at the same time.Our results confirmed that EDARV370A,a genetic variant that first originated in East Asia about 30000 years ago,played an important role in incisor shoveling in East Asia.This finding suggested that incisor shoveling in modern humans in East Asia is likely to have appeared after the late Pleistocene.

Association between peroxisome proliferator-activated receptor γ gene polymorphism and susceptibility to northwest dryness syndrome

OBJECTIVE:To investigate the relationship between gene polymorphism of peroxisome proliferator-activated receptor(PPAR) and susceptibility to northwest dryness syndrome(NDS).METHODS:The polymorphisms of 11 PPARl51, rs13γ7 gene oci rs10510418, rs1263353640,rs17036188, rs2921190, rs4135247, rs4135275,rs4135283, rs6768587, rs709156, and rs7615916 were detected in 249 patients with NDS and 260 patients with non-NDS(control group) by using Snapshot single-nucleotide polymorphism typing technology.RESULTS:All locus detections were in accordance with Hardy-Weinberg equilibrium test.Compared with the control group, rs2921190 genotype frequency showed statistical difference in the NDS group(P < 0.05).Two-two comparison result showed that CC genotype frequency in the NDS group was higher than that in the control group.CT and TT genotype distribution frequencies showed differences between the two groups.The rare allele frequency in the NDS group was lower than that of the control group(P < 0.01).Multi-factor logistic regression analysis showed that the age and genotype entered the regression equation.The subjects in the age bracket 30-55 and 45-45 were1.796 and 1.561 times likely, respectively, than those in other age brackets to contract NDS,.The patients with CC genotype was only 0.524 times likely than those with CT/TT genotype to suffer from NDS.CONCLUSION:PPARsm was correlated γw gene rs2921190 polymorphiith the susceptibility to NDS.