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Ye Z.,Nankai University | Zhu G.,Tianjin Normal University | Chen P.,Netherlands Biodiversity Center Naturalis | Zhang D.,Nankai University | Bu W.,Nankai University
Molecular Ecology | Year: 2014

This study investigated the Pleistocene history of a semi-aquatic bug, Microvelia douglasi douglasi Scott, 1874 (Hemiptera: Veliidae) in East Asia. We used M. douglasi douglasi as a model species to explore the effects of historical climatic fluctuations on montane semi-aquatic invertebrate species. Two hypotheses were developed using ecological niche models (ENMs). First, we hypothesized that M. douglasi douglasi persisted in suitable habitats in southern Guizhou, southern Yunnan, Hainan, Taiwan and southeast China during the LIG. After that, the populations expanded (Hypothesis 1). As the spatial prediction in the LGM was significantly larger than in the LIG, we then hypothesized that the population expanded during the LIG to LGM transition (Hypothesis 2). We tested these hypotheses using mitochondrial data (COI+COII) and nuclear data (ITS1 + 5.8S+ITS2). Young lineages, relatively deep splits, lineage differentiation among mountain ranges in central, south and southwest China and high genetic diversities were observed in these suitable habitats. Evidence of mismatch distributions and neutrality tests indicate that a population expansion occurred in the late Pleistocene. The Bayesian skyline plot (BSP) revealed an unusual population expansion that likely happened during the cooling transition between LIG and LGM. The results of genetic data were mostly consistent with the spatial predictions from ENM, a finding that can profoundly improve phylogeographic research. The ecological requirements of M. douglasi douglasi, together with the geographical heterogeneity and climatic fluctuations of Pleistocene in East Asia, could have shaped this unusual demographic history. Our study contributes to our knowledge of semi-aquatic bug/invertebrate responses to Pleistocene climatic fluctuations in East Asia. © 2014 John Wiley & Sons Ltd.

Ye Z.,Nankai University | Chen P.,Netherlands Biodiversity Center Naturalis | Bu W.,Nankai University
Zootaxa | Year: 2015

Five species of genus Strongylovelia Esaki are now known from China. Of these, S. formosa Esaki, 1924 is the only member of the genus previously recorded from China and S. paitooni Chen, Nieser & Sangpradub, 2006 is newly recorded from China. In addition, three species, S. balteiformis sp. n., S. fasciaria sp. n. and S. hainanensis sp. n. are described as new to science. Photographs of the female and male dorsal habitus, male abdominal segment VIII, and male genitalic structures are provided, accompanied by line drawings of the female body in lateral view, views perpendicular to the distal part of the male paramere, and a distribution map for all Chinese Strongylovelia species. A key to the all five Chinese Strongylovelia species is also provided to assist in future identification. Copyright © 2015 Magnolia Press.

Gorelick R.,Carleton University | Fraser D.,Carleton University | Zonneveld B.J.M.,Netherlands Biodiversity Center Naturalis | Little D.P.,New York Botanical Garden
International Journal of Plant Sciences | Year: 2014

Premise of research: Change in base number of chromosomes per nucleus is usually believed to result from whole-genome duplication or from duplication or elimination of a single chromosome (aneuploidy). However, chromosome numbers can also change via mechanisms with no gain or loss of nuclear DNA, such as fusion or fission of chromosomes.Methodology: We previously determined amount of DNA per nucleus (2C values) using flow cytometry of leaf tissue. We tested whether Cycadales (cycad) chromosome numbers are correlated with these 2C values using ordinary least squares (OLS) and phylogenetic generalized least squares (PGLS) regression.Pivotal results: Regardless of branch length estimation technique and evolutionary model, OLS and PGLS yielded no statistically significant relationship between chromosome number and genome size in our analysis of 22 species, encompassing all 11 extant cycad genera.Conclusions: Within cycad genera, chromosomal fissions or fusions are much more likely than large additions or deletions of nuclear DNA. © 2014 by The University of Chicago. All rights reserved.

Ye Z.,Nankai University | Chen P.,Netherlands Biodiversity Center Naturalis | Bu W.,Nankai University
Zootaxa | Year: 2013

Five species of the genus Perittopus Fieber, 1861 from China and Thailand are treated in this paper including four new species: P. crinalis sp. nov., P. falciformis sp. nov., and P. yunnanensis sp. nov. are from Yunnan Province, China; and P. zhengi sp. nov. from Chiang Mai, Thailand. The morphological descriptions are given for all the treated species. The photographs and the drawings of female habitus and male and female diagnostics are provided. A key to these five species is provided. The discussion on the identity of P. asiaticus Zettel, 2001 is given. © 2013 Magnolia Press.

Aflitos S.,Plant Research International | Aflitos S.,Wageningen University | Schijlen E.,Plant Research International | De Jong H.,Wageningen University | And 55 more authors.
Plant Journal | Year: 2014

We explored genetic variation by sequencing a selection of 84 tomato accessions and related wild species representative of the Lycopersicon, Arcanum, Eriopersicon and Neolycopersicon groups, which has yielded a huge amount of precious data on sequence diversity in the tomato clade. Three new reference genomes were reconstructed to support our comparative genome analyses. Comparative sequence alignment revealed group-, species- and accession-specific polymorphisms, explaining characteristic fruit traits and growth habits in the various cultivars. Using gene models from the annotated Heinz 1706 reference genome, we observed differences in the ratio between non-synonymous and synonymous SNPs (dN/dS) in fruit diversification and plant growth genes compared to a random set of genes, indicating positive selection and differences in selection pressure between crop accessions and wild species. In wild species, the number of single-nucleotide polymorphisms (SNPs) exceeds 10 million, i.e. 20-fold higher than found in most of the crop accessions, indicating dramatic genetic erosion of crop and heirloom tomatoes. In addition, the highest levels of heterozygosity were found for allogamous self-incompatible wild species, while facultative and autogamous self-compatible species display a lower heterozygosity level. Using whole-genome SNP information for maximum-likelihood analysis, we achieved complete tree resolution, whereas maximum-likelihood trees based on SNPs from ten fruit and growth genes show incomplete resolution for the crop accessions, partly due to the effect of heterozygous SNPs. Finally, results suggest that phylogenetic relationships are correlated with habitat, indicating the occurrence of geographical races within these groups, which is of practical importance for Solanum genome evolution studies. © 2014 The Authors.

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