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Subspecies Designations (subspecy + designation)
Selected AbstractsBiogeographical patterns of genetic differentiation in dung beetles of the genus Trypocopris (Coleoptera, Geotrupidae) inferred from mtDNA and AFLP analysesJOURNAL OF BIOGEOGRAPHY, Issue 7 2004Loredana Carisio Abstract Aim, To examine the phylogeography and population structure of three dung beetle species of the genus Trypocopris (Coleoptera, Geotrupidae). We wanted to test whether genetic differences and genealogies among populations were in accordance with morphologically described subspecies and we aimed to establish times of divergence among subspecies to depict the appropriate temporal framework of their phylogeographical differentiation. We also wished to investigate the historical demographic events and the relative influences of gene flow and drift on the distribution of genetic variability of the different populations. Location, Europe (mostly Italy). Methods, We collected adult males from dung pats from 15 Italian localities over the period 2000,2002. For sequence analysis, some dried specimens from Albania, Croatia, Slovakia and Spain were also used. We applied cytochrome oxidase I mitochondrial DNA sequencing and the amplified fragment length polymorphism (AFLP) technique to determine whether phylogeographical patterns within the three species support the proposed hypotheses of subspecies designations, and to detect further structure among populations that might mediate diversification. Results and main conclusions, The results show a high concordance between the distribution of mtDNA variation and the main morphological groups recognized as subspecies, which thus may represent independent evolutionary units. The degree of mitochondrial divergence suggests that speciation events occurred during the Pliocene, while diversification of the main subspecific lineages took place in the Pleistocene, from c. 0.3 to 1.5 Ma. Mitochondrial and nuclear data also reveal that there is phylogeographical structuring among populations within each of the main groups and that both contemporary and historical processes determined this pattern of genetic structure. Geographical populations form monophyletic clades in both phylogenetic and network reconstructions. Despite the high levels of intrapopulational diversity, FST values indicate moderate but significant genetic differentiation among populations, and a Bayesian clustering analysis of the AFLP data clearly separates the geographical populations. Nucleotide and gene diversity estimates reveal interspecific differences in the degree of diversification among populations that may be related to the different ecological requirements of the three species. [source] Inter-ocean dispersal is an important mechanism in the zoogeography of hakes (Pisces: Merluccius spp.)JOURNAL OF BIOGEOGRAPHY, Issue 6 2001W. Stewart Grant Aim To present new genetic data and to review available published genetic data that bear on the phylogeny of hakes in the genus Merluccius. To construct a zoogeographical model from a summary phylogenetic tree with dated nodes. To search for an explanation of antitropical distributions in hakes. To assess peripheral isolate, centrifugal and vicariance models of speciation in view of the molecular phylogeny and zoogeography of hakes. Locations Northern and southern Atlantic Ocean, eastern Pacific Ocean, South Pacific Ocean. Methods Electrophoretic analysis of 20 allozyme loci in 10 species of hakes. Phylogenetic tree construction with parsimony and bootstrap methods. Reanalysis of previous genetic data. Analysis of zoogeographical patterns with geographical distributions of molecular genetic markers. Results Phylogenetic analyses of new and previous allozyme data and previous mitochondrial DNA data indicate a deep genetic partition between Old- and New-World hakes with genetic distances corresponding to 10,15 Myr of separation. This time marks a widening rift between Europe and North America and a rapid drop in ocean temperatures that subdivided an ancestral population of North Atlantic hake. Two Old-World clades spanning the equator include pairs of sister taxa separated by tropical waters. Divergence times between these pairs of sister-taxa variously date to the early Pliocene and late Pleistocene. Amongst New-World hakes, pairs of sister taxa are separated by equatorial waters, by the Southern Ocean, and by the Panama Isthmus. These genetic separations reflect isolation by the rise of the Isthmus 3,4 Ma and by Pliocene and Pleistocene dispersals. Pairs of species occurring in sympatry or parapatry in six regions do not reflect sister-species relationships, but appear to reflect allopatric divergence and back dispersals of descendent species. Some geographically isolated regional populations originating within the last few hundreds of thousands of years merit subspecies designations. Conclusions Vicariance from tectonic movement of continental plates or ridge formation cannot account for the disjunct distributions of most hake sister taxa. Molecular genetic divergences place the origin of most hake species diversity in the last 2,3 Myr, a period of negligible tectonic activity. Distributions of many hake species appear to have resulted from dispersals and back dispersals across both warm equatorial waters and cool waters in the Southern Ocean, driven by oscillations in climate and ocean temperatures. Genetic and ecological divergence prevents hybridization and competitive exclusion between sympatric species pairs in six regions. Sister-taxa relationships and estimates of divergence are consistent with the modified peripheral isolate model of speciation in which vicariances, range expansions and contractions, dispersals and founder events lead to isolated populations that subsequently diverge to form new species. [source] Bottlenecks, drift and differentiation: the population structure and demographic history of sika deer (Cervus nippon) in the Japanese archipelagoMOLECULAR ECOLOGY, Issue 6 2001Simon J. Goodman Abstract We assessed genetic differentiation and diversity in 14 populations of sika deer (Cervus nippon) from Japan and four populations of sika deer introduced to the UK, using nine microsatellite loci. We observed extreme levels of differentiation and significant differences in diversity between populations. Our results do not support morphological subspecies designations, but are consistent with previous mitochondrial DNA analyses which suggest the existence of two genetically distinct lineages of sika deer in Japan. The source of sika introduced to the UK was identified as Kyushu. The underlying structure of Japanese populations probably derives from drift in separate glacial refugia and male dispersal limited by distance. This structure has been perturbed by bottlenecks and habitat fragmentation, resulting from human activity from the mid-nineteenth century. Most current genetic differentiation and differences in diversity among populations probably result from recent drift. Coalescent model analysis suggests sika on each of the main Japanese islands have experienced different recent population histories. Hokkaido, which has large areas of continuous habitat, has maintained high levels of gene flow. In Honshu the population is highly fragmented and is likely to have been evolving by drift alone. In Kyushu there has been a balance between gene flow and drift but all the populations have experienced high levels of drift. Habitat fragment size was not significantly associated with genetic diversity in populations but there was a significant correlation between habitat fragment size and effective population size. [source] Morphological variation in Gallotia atlantica from the volcanic island of Lanzarote: subspecies designations and recent lava flowsBIOLOGICAL JOURNAL OF THE LINNEAN SOCIETY, Issue 3 2005PAUL BLOOR A detailed uni- and multivariate analysis of within-island geographical variation in scalation and body dimensions of the lacertid lizard, Gallotia atlantica, from Lanzarote (and two neighbouring offshore islets) was carried out. Two main morphological groupings were detected: four populations clustered within a putative malpaís group, i.e. from relatively recent volcanic lava fields (seven populations were sampled from these areas), while the other 19 populations (including the three remaining malpaís populations, and those from the offshore islets of Montaña Clara and Alegranza) also clustered together. Thus, while there is a tendency for occupation of malpaís areas to be related to morphological variation, this model does have some inconsistencies. The differentiated malpaís group comprises populations from two geographically isolated areas, one from the central-western part of the island (Timanfaya) and the other from the north (Malpaís de la Corona). The divergence of these populations is considered to have arisen recently, rather than their being relicts of an ancient, formerly widespread, lineage. The morphological variation partially supports the previous use of two different subspecies to describe the within-island variation. However, if such a scheme were applied then one of the subspecies would need to encompass populations from the geographically separated southern Timanfaya and Malpaís de la Corona areas, as opposed to just the latter. We reject previous observations that either malpaís individuals in general, or those corresponding to the north-eastern subspecies, are larger than individuals from other areas. The pattern of morphological variation of G. atlantica within Lanzarote is less pronounced but shows some similarities with patterns of morphological variation in lizards from neighbouring islands. © 2005 The Linnean Society of London, Biological Journal of the Linnean Society, 2005, 85, 395,406. [source] | ||||||||||