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61.
Burgos JM Altcheh J Bisio M Duffy T Valadares HM Seidenstein ME Piccinali R Freitas JM Levin MJ Macchi L Macedo AM Freilij H Schijman AG 《International journal for parasitology》2007,37(12):1319-1327
Congenital transmission of Trypanosoma cruzi may occur in some or all the gestations from a T. cruzi-infected mother. Variable rates of congenital transmission have been reported in different geographical areas where different parasitic strains predominate, suggesting that parasitic genotypes might play a role in the risk of congenital transmission. Moreover, in cases of transmission it is unknown if the whole maternal T. cruzi population or certain clones are preferentially transmitted by the transplacental route. In this study, bloodstream T. cruzi lineages were identified in blood samples from congenitally infected children, transmitting and non-transmitting mothers and unrelated Chagas disease patients, using improved PCR strategies targeted to nuclear genomic markers. T. cruzi IId was the prevalent genotype among 36/38 PCR-positive congenitally infected infants, 5/5 mothers who transmitted congenital Chagas disease, 12/13 mothers who delivered non-infected children and 28/34 unrelated Chagas disease patients, all coming from endemic localities of Argentina and Bolivia. These figures indicate no association between a particular genotype and vertical transmission. Furthermore, minicircle signatures from the maternal and infants' bloodstream trypanosomes were profiled by restriction fragment length polymorphism of the 330-bp PCR-amplified variable regions in seven cases of mothers and congenitally infected infants. Minicircle signatures were nearly identical between each mother and her infant/s and unique to each mother-infant/s case, a feature that was also observed in twin deliveries. Moreover, allelic size polymorphism analysis of microsatellite loci from populations transmitted to twins showed that all clones from the maternal polyclonal population were equally infective to both siblings. 相似文献
62.
63.
Phillip C. Watts David J. Thompson Katherine A. Allen Stephen J. Kemp 《Journal of Insect Conservation》2007,11(2):195-198
DNA obtained from museum specimens provides a historical perspective on levels of genetic diversity. Archived samples are
irreplaceable so it is desirable that only parts of the specimens are used, which constrains the amount of DNA obtained from
small taxa. However, at present there are no quantitative data on yields of DNA from such samples. In this paper we determine
the amount of DNA that may be extracted from the legs of museum-archived specimens of the damselfly Coenagrion mercuriale (Charpentier) and the suitability of this DNA for PCR-amplification of nuclear genetic loci (microsatellites). We find that
(i) the yield of DNA correlates with the genotyping success rate and (ii) the amount of DNA obtained from the legs decreases
with time since sample collection until 1954, before which no DNA could be detected (although DNA may be present in very low
quantities). This cut-off point for successful DNA extraction corresponds with the date until reliable genotypes could be
obtained by routine PCR. Thus, air-dried insect legs more than 50 years old appear to have limited usefulness for studies
that seek to amplify many nuclear loci without the use of other techniques that may be used to increase the possible low-quantities
of template DNA present. 相似文献
64.
We characterized fifteen microsatellite markers for the butterfly Maniola jurtina. For the six studied populations (96 samples) the total number of alleles per locus ranged from 3 to 55 and mean overall expected heterozygosity across all loci was 0.74. In spite of a high frequency of null alleles detected in part of the loci, a recurrent phenomenon in Lepidopteron, the estimation of pairwise FST seems rather insensitive to the presence of these null alleles as shown by the high correlation between FST calculated after correction for the presence of null alleles and non-corrected FST, indicating that the loci may be usable in population genetics, more specifically for the study of populations genetics structure. 相似文献
65.
Assessment of genetic diversity among androdioecious ancient Osmanthus fragrans trees by SSR markers
The well known ornamental plant, Osmanthus fragrans, is one of the rare androdioecious species in nature. Determining the genetic diversity of this species may assist in its conservation and genetic improvement. Data of 10 ancient tree populations of O. fragrans were used to assess its genetic diversity and population structure with microsatellite markers. A high level of genetic diversity was observed with POPGENE. As anticipated the heterozygosity of ancient hermaphrodite trees was higher than male ones, although the number of hermaphrodites was far fewer than males. Abundant gene exchange between males and hermaphrodites was detected, and trees from the same population often clustered together. Androdioecy is an important factor that determines the genetic structure of O. fragrans and there is an urgent need to conserve ancient O. fragrans germplasms especially the hermaphrodites. 相似文献
66.
Y chromosome haplotype distribution of brown bears (Ursus arctos) in Northern Europe provides insight into population history and recovery
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Julia Schregel Hans Geir Eiken Finn Audun Grøndahl Frank Hailer Jouni Aspi Ilpo Kojola Konstantin Tirronen Piotr Danilov Alexander Rykov Eugene Poroshin Axel Janke Jon E. Swenson Snorre B. Hagen 《Molecular ecology》2015,24(24):6041-6060
High‐resolution, male‐inherited Y‐chromosomal markers are a useful tool for population genetic analyses of wildlife species, but to date have only been applied in this context to relatively few species besides humans. Using nine Y‐chromosomal STRs and three Y‐chromosomal single nucleotide polymorphism markers (Y‐SNPs), we studied whether male gene flow was important for the recent recovery of the brown bear (Ursus arctos) in Northern Europe, where the species declined dramatically in numbers and geographical distribution during the last centuries but is expanding now. We found 36 haplotypes in 443 male extant brown bears from Sweden, Norway, Finland and northwestern Russia. In 14 individuals from southern Norway from 1780 to 1920, we found two Y chromosome haplotypes present in the extant population as well as four Y chromosome haplotypes not present among the modern samples. Our results suggested major differences in genetic connectivity, diversity and structure between the eastern and the western populations in Northern Europe. In the west, our results indicated that the recovered population originated from only four male lineages, displaying pronounced spatial structuring suggestive of large‐scale population size increase under limited male gene flow within the western subpopulation. In the east, we found a contrasting pattern, with high haplotype diversity and admixture. This first population genetic analysis of male brown bears shows conclusively that male gene flow was not the main force of population recovery. 相似文献
67.
A phylogeographical perspective on the ex situ conservation of Aylacostoma (Thiaridae,Gastropoda) from the High Paraná River (Argentina–Paraguay)
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Roberto E. Vogler Ariel A. Beltramino Ellen E. Strong Juana G. Peso Alejandra Rumi 《Zoological Journal of the Linnean Society》2015,174(3):487-499
Aylacostoma Spix, 1827, contains species that are the subject of focused conservation efforts under the auspices of the ‘Aylacostoma Project’, the only ex situ conservation programme for freshwater gastropods in South America. Two species from the High Paraná River (Argentina–Paraguay) are included in this programme (Aylacostoma chloroticum Hylton Scott, 1954 and Aylacostoma brunneum Vogler & Peso, 2014), as their habitats have disappeared as a consequence of the filling of the Yacyretá Reservoir in the 1990s. At present, A. chloroticum is restricted to only one known wild population in a small and fragile habitat, and wild populations of A. brunneum are presumed to have gone extinct. We used partial sequences of the cytochrome oxidase subunit I gene to provide the first phylogeographical perspective on these species from a limited dataset containing representatives of several wild populations that are successfully being bred in captivity. We found low genetic diversity and two haplotypes in A. chloroticum, and absence of variation with one haplotype in A. brunneum. The reservoir's entry zone was identified to be of great interest for conservation, and is where we suggest re‐introductions and translocations should be targeted, to preserve the future evolutionary potential of the extant diversity. © 2015 The Linnean Society of London 相似文献
68.
Kit-Siong Liew Wei-Seng Ho Shek-Ling Pang Abdullah Julaihi 《Physiology and Molecular Biology of Plants》2015,21(1):163-165
Duabanga moluccana (or locally known as sawih) is an indigenous fast growing tropical tree species that confers various advantages for the timber industry and for planted forests development. In this paper, we isolated and characterized 8 polymorphic microsatellite markers from the D. moluccana genome using ISSR-suppression PCR techniques. The number of alleles and PIC values ranged from 3 to 8 alleles per locus and from 0.488 to 0.792, respectively. Three microsatellite loci were deviated from Hardy-Weinberg equilibrium (P < 0.05). The transferability rate ranged from 24 to 100 % among the three indigenous tree species tested. This indicates that the newly developed microsatellite markers would be useful tools for population genetic studies on D. moluccana and other indigenous tree species. 相似文献
69.
Eriston Vieira Gomes Lucas Breseguello
Do Nascimento Marcos Augusto
De Freitas Luiz Carlos Bhering Nasser Silvana Petrofeza 《Journal of Phytopathology》2011,159(2):94-99
Microsatellites are powerful markers to infer population genetic parameters. We used 10 microsatellite loci to characterize the genetic diversity and structure of 79 samples of Sclerotinia sclerotiorum isolated from four Brazilian dry bean populations and observed that eight of them were polymorphic within populations. We identified 102 different haplotypes ranging from 6 to 18 per locus. Analyses based on genetic diversity and fixation indices indicated variability among and within populations of 28.79% (FST = 28793) and 71.21%, respectively. To examine genetic relatedness among S. sclerotiorum isolates, we used internal spacer (ITS1‐5.8S‐ITS2) restriction fragment length polymorphism (PCR‐RFLP) and sequencing analysis. PCR‐RFLP analysis of these regions failed to show any genetic differences among isolates. However, we detected variability within the sequence, which does not support the hypothesis of clonal populations within each population. High variability within and among populations may indicate the introduction of new genotypes in the areas analysed, in addition to the occurrence of clonal and sexual reproduction in the populations of S. sclerotiorum in the Brazilian Cerrado. 相似文献
70.
应用微卫星标记研究Dunkin Hartley豚鼠封闭群的遗传背景 总被引:1,自引:0,他引:1
目的检测我国现有Dunkin Hartley豚鼠封闭的遗传背景,分析评估其遗传多样性水平和遗传分离情况,为建立标准化的豚鼠封闭群监测方法提供基础资料。方法应用筛选获得的8个微卫星位点,从一个数量为1000的豚鼠封闭群中随机选择72个个体,通过PCR扩增和聚丙烯酰胺凝胶电泳的方法,进行等位基因检测。并根据检测结果分析评估了该豚鼠封闭群的遗传现状。结果共检测到28个等位基因,每个座位的等位基因数为2~5个,有效等位基因数为1.5191~3.4422,平均2.3093。平均期望杂合度为0.5294。各位点多态信息含量在0.3154~0.6545之间,平均值为0.4687。有5个位点显著偏离Hardy-Weinberg平衡。结论豚鼠封闭群的遗传多态性处于中等水平,遗传平衡检测结果提示种群的繁殖过程未能实现完全随机交配,近交现象一定程度上存在。本研究的结果将为豚鼠封闭群遗传监测方法和标准的建立提供基础。 相似文献