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Multiple Haplotypes (multiple + haplotype)
Selected AbstractsCombining mitochondrial DNA sequences and morphological data to infer species boundaries: phylogeography of lanceheaded pitvipers in the Brazilian Atlantic forest, and the status of Bothrops pradoi (Squamata: Serpentes: Viperidae)JOURNAL OF EVOLUTIONARY BIOLOGY, Issue 4 2001G. Puorto Phylogeographic studies using mitochondrial DNA sequence information are frequently used as the principal source of evidence to infer species boundaries. However, a critical analysis of further evidence is essential to test whether different haplotype clades identify different species. We demonstrate a hypothesis-testing approach, using a combination of phylogeographic methods, multivariate morphometrics and matrix association tests, to investigate species boundaries in eastern Brazilian pitvipers conventionally assigned to the species Bothrops leucurus and B. pradoi. Two basal haplotype clades with partly overlapping geographical distributions are identified, which could either represent two partly sympatric species, or multiple haplotypes within one organismal lineage. We use partial Mantel matrix association tests to verify whether generalized morphology, or any of four supposedly diagnostic characters for the two species, show any association with mtDNA variation. Negative results lead to the conclusion that the haplotype clades do not denote independently evolving organismal lineages, and do not constitute separate species under any criterion. [source] Phylogeographical structure and temporal complexity in American sweetgum (Liquidambar styraciflua; Altingiaceae)MOLECULAR ECOLOGY, Issue 17 2008ASHLEY B. MORRIS Abstract Eastern North American plant biogeography has traditionally focused on two primary issues: (i) the location of temperate Pleistocene refugia and their proximity to the southern margin of the ice sheet during the last glacial maximum, and (ii) the origin of the temperate element of northern Latin America. While numerous population genetic and phylogeographical studies have focused on the first issue, few (if any) have considered the second. We addressed these issues by surveying 117 individuals from 24 populations of Liquidambar styraciflua (American sweetgum; Altingiaceae) across the southeastern USA, eastern Mexico, and Guatemala, using more than 2200 bp of chloroplast DNA sequence data. To specifically address the issue of timing, we estimated intraspecific divergence times on the basis of multiple fossil-based calibration points, using taxa from Altingiaceae (Liquidambar and Altingia) and Hammamelidaceae (Hamamelis) as outgroups. More than half of the sampled localities exhibited multiple haplotypes. Remarkably, the greatest variation was observed within the USA, with Mexico and Guatemala sharing widespread haplotypes with Texas, Mississippi, Kentucky, Ohio, and northern Virginia. This lack of differentiation suggests shared ancestral polymorphisms, and that the genetic signal we observed is older than the disjunction itself. Our data provide support for previously proposed hypotheses of Pleistocene refugia in peninsular Florida and along the eastern Atlantic, but also for deeper divergences (~8 million years ago) within the USA. These patterns reflect a dynamic biogeographical history for eastern North American trees, and emphasize the importance of the inclusion of a temporal component in any phylogeographical study. [source] Genetic distinctness and phylogenetic relationships among Undaria species (Laminariales, Phaeophyceae) based on mitochondrial cox3 gene sequencesPHYCOLOGICAL RESEARCH, Issue 4 2007Shinya Uwai SUMMARY Genetic relationships among Undaria species and among populations of each species were studied based on DNA sequences of the mitochondrial cox3 gene. Although three Undaria species, U. peterseniana (Kjellman) Okamura, U. pinnatifida (Harvey) Suringar and U. undarioides (Yendo) Okamura, have been described based mostly on blade morphology, plants with intermediate morphologies have also been found. Multiple plants from several populations in Japan were collected. Morphological characters could identify most of the samples unambiguously. A few samples with intermediate morphologies were also collected. Mitochondrial haplotypes found in each population were different for each identified species, and each species had multiple haplotypes. In the cox3 haplotype network analysis, the numbers of steps between haplotypes within and between species were similar, and haplotypes of each species did not group together. The close genetic relationships among species strongly suggest that these species are conspecific. Alternatively, recent speciation could be possible with maintenance of ancestral polymorphisms within the species (i.e. incomplete lineage sorting). Haplotypes of samples with intermediate morphologies were different for each sample and the same as ones found in the local population, suggesting interspecific hybridizations among species. [source] GJB2 Mutations in Mongolia: Complex Alleles, Low Frequency, and Reduced Fitness of the DeafANNALS OF HUMAN GENETICS, Issue 2 2010Mustafa Tekin SUMMARY We screened the GJB2 gene for mutations in 534 (108 multiplex and 426 simplex) probands with non-syndromic sensorineural deafness, who were ascertained through the only residential school for the deaf in Mongolia, and in 217 hearing controls. Twenty different alleles, including four novel changes, were identified. Biallelic GJB2 mutations were found in 4.5% of the deaf probands (8.3% in multiplex, 3.5% in simplex). The most common mutations were c.IVS1 + 1G > A (c.-3201G > A) and c.235delC with allele frequencies of 3.5% and 1.5%, respectively. The c.IVS1 + 1G > A mutation appears to have diverse origins based on associated multiple haplotypes. The p.V27I and p.E114G variants were frequently detected in both deaf probands and hearing controls. The p.E114G variant was always in cis with the p.V27I variant. Although in vitro experiments using Xenopus oocytes have suggested that p.[V27I;E114G] disturbs the gap junction function of Cx26, the equal distribution of this complex allele in both deaf probands and hearing controls makes it a less likely cause of profound congenital deafness. We found a lower frequency of assortative mating (37.5%) and decreased genetic fitness (62%) of the deaf in Mongolia as compared to the western populations, which provides an explanation for lower frequency of GJB2 deafness in Mongolia. [source] | ||||||||||