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Western Group (western + group)
Selected AbstractsGenetic profiling of the Azores Islands (Portugal): Data from 10 X-chromosome STRsAMERICAN JOURNAL OF HUMAN BIOLOGY, Issue 2 2010Francisca Silva The populations from the Azores islands have been the target of several genetic studies, using data derived from monoparental and recombining genetic systems. These studies have provided a complex picture of the genetic landscape of the three groups of Azorean islands, and further data are required to assess its genetic profile. We present a study of the polymorphism in 10 X-chromosome STR loci (DSXS8378, DXS9898, DXS7133, GATA31E08, GATA172D05, DXS7423, DXS6809, DXS7132, DXS9902, DXS6789) conducted on a total of 304 chromosomes (97 females and 110 males) of unrelated individuals with Azorean ancestry. Average gene diversity was 74.47%, ranging from 66.21% (DXS7133) to 81.19% (GATA172D05). No shared haplotypes were found. Genotype frequencies among females displayed conformity with Hardy-Weinberg expectations for all loci. Pairwise linkage disequilibrium tests did not reveal evidences of association between the studied markers. Significant differences in allelic frequencies between the Western and the Eastern group of islands are in agreement with previous results from mitochondrial DNA and Y chromosome studies, providing further evidence that the Azores cannot be considered an homogeneous population. Moreover, differences between the Western group and the North of Portugal are also reported, supporting the pertinence of a specific database for the Azores populations, on what concerns the genetic markers analyzed. Am. J. Hum. Biol., 2010. © 2009 Wiley-Liss, Inc. [source] Conservation and management implications of fine-scale genetic structure of Gulf sturgeon in the Pascagoula River, MississippiJOURNAL OF APPLIED ICHTHYOLOGY, Issue 4 2004M. A. Dugo Summary The anadromous Gulf sturgeon occurs along the north central coast of the Gulf of Mexico and is federally listed as threatened. We analyzed fine-scale patterns of Gulf sturgeon population structure, focusing on the Pascagoula River drainage of Mississippi, in reference to movement patterns as determined via telemetry and capture data. We genotyped 361 Gulf sturgeon using eight microsatellite loci including samples from the Pascagoula, Pearl, Escambia, Yellow, Choctawhatchee, and Apalachicola river drainages. Pairwise FST estimates indicated that genetic structure occurs at least at the drainage level. The Pascagoula and Pearl rivers form a western group, demonstrating 100% bootstrap support for a division with drainages to the east. Assignment tests detected non-natal genotypes occurring in all drainages. According to assignment tests, the Pascagoula supports an admixture of individuals, containing minimal influence from drainages to the east (2%) and substantial interaction with the Pearl River (14.1%). The occurrence of Pascagoula River fish in the Pearl was non-reciprocal, observed at 1.1%. After accounting for non-natal genetic diversity within the Pascagoula, there remained a disparity between a pooled Pascagoula group and the only documented spawning site within the drainage located in the Bouie River. We interpret this as an indication of a second genetic stock within the Pascagoula River drainage. Radio telemetry data suggest that spawning likely occurs in the Chickasawhay River, in areas isolated from the Bouie River spawning site by about 350 river kilometers. We emphasize the utility of integrating field and molecular approaches when delineating fine-scale patterns of population structure in anadromous fishes. [source] Historical colonization and demography of the Mediterranean damselfish, Chromis chromisMOLECULAR ECOLOGY, Issue 13 2005VERA S. DOMINGUES Abstract The desiccation of the Mediterranean Sea during the Messinian Salinity Crisis 6.0,5.3 million years ago (Ma), caused a major extinction of the marine ichthyofauna of the Mediterranean. This was followed by an abrupt replenishment of the Mediterranean from the Atlantic after the opening of the Strait of Gibraltar. In this study, we combined demographic and phylogeographic approaches using mitochondrial and nuclear DNA markers to test the alternative hypotheses of where (Atlantic or Mediterranean) and when (before or after the Messinian Salinity Crisis) speciation occurred in the Mediterranean damselfish, Chromis chromis. The closely related geminate transisthmian pair Chromis multilineata and Chromis atrilobata was used as a way of obtaining an internally calibrated molecular clock. We estimated C. chromis speciation timing both by determining the time of divergence between C. chromis and its Atlantic sister species Chromis limbata (0.93,3.26 Ma depending on the molecular marker used, e.g. 1.23,1.39 Ma for the control region), and by determining the time of coalescence for C. chromis based on mitochondrial control region sequences (0.14,0.21 Ma). The time of speciation of C. chromis was always posterior to the replenishment of the Mediterranean basin, after the Messinian Salinity Crisis. Within the Mediterranean, C. chromis population structure and demographic characteristics revealed a genetic break at the Peloponnese, Greece, with directional and eastbound gene flow between western and eastern groups. The eastern group was found to be more recent and with a faster growing population (coalescent time = 0.09,0.13 Ma, growth = 485.3) than the western group (coalescent time = 0.13,0.20 Ma, growth = 325.6). Our data thus suggested a western origin of C. chromis, most likely within the Mediterranean. Low sea water levels during the glacial periods, the hydrographic regime of the Mediterranean and dispersal restriction during the short pelagic larval phase of C. chromis (18,19 days) have probably played an important role in C. chromis historical colonization. [source] Evolutionary history of the land snail Helix aspersa in the Western Mediterranean: preliminary results inferred from mitochondrial DNA sequencesMOLECULAR ECOLOGY, Issue 1 2001A. Guiller Abstract Intraspecific phylogeographic methods provide a means of examining the history of genetic exchange among populations. As part of a study of the history of Helixaspersa in the Western Mediterranean, we performed a phylogenetic analysis based on partial sequences of the mitochondrial large ribosomal subunit (16S) gene. Our samples include 31 H. a. aspersa populations from North Africa previously investigated for anatomical and biochemical characters. To clarify subspecific relationships, three individuals of the subspecies H. a. maxima were also studied. The molecular phylogeny inferred agrees largely with previous results, in splitting H. a. aspersa haplotypes into an eastern and a western group. H. a. maxima haplotypes form a third lineage arising before the H. a.aspersa groups. Divergence times estimated between the lineages suggest that dispersal during Pleistocene glaciation and vicariance events due to Pliocene geological changes in the western Mediterranean may both have played a significant part in the establishment of the present range of H. aspersa. [source] Molecular systematics in the genus Clintonia and related taxa based on rbcL and matK gene sequence dataPLANT SPECIES BIOLOGY, Issue 2 2001Kazuhiko Hayashi Abstract In an attempt to elucidate the affinity and phylogeny of the disjunct North American,eastern Asian genus Clintonia, two chloroplast genes, rbcL and matK, were sequenced for all five species (Clintonia andrewsiana, Clintonia borealis, Clintonia umbellulata, Clintonia uniflora and Clintonia udensis). Similar sequence data sets for both genes supported the idea that a monophyly of Clintonia consists of two clades, one in eastern Asia and one in North America. The North American lineage resolves into an eastern group and a western group. There are surprisingly few site substitutions within these two genes, notwithstanding the wide morphological diversity of the genus. To root the Clintonia trees, Cardiocrinum (=Lilium) cordatum, Medeola virginiana, Scoliopus bigelovii and Scoliopus hallii were used as outgroup taxa. Similar topologies for Clintonia resulted when both the rbcL and matK gene sequences were combined. However, when an amino acid tree was generated for the matK sequence, all differences between the North American species were reduced to similarities due to synonymous codon sequences. Differentiation patterns of some selected morphological, karyological and embryological characters in Clintonia were also reviewed in comparison to the resulting molecular topologies. The unique, Clintonia -type megasporogenesis that produced identical, maternally derived, diploid zygotes and endosperm coupled to polyploid buffering provides a considerable constraint on variability. A search of possible sister genera to Clintonia was also attempted based on the molecular analyses and outgroup analysis, and Medeola virginiana from eastern North America turned out to be the closest relative found. [source] | ||||||||||