Mitochondrial DNA diversity of the long-tailed macaque (Macaca fascicularis) from the northern region of Peninsular Malaysia

We examined the genetic diversity of 64 long-tailed macaques from the northern states of Peninsular Malaysia covering the states of Perlis and Kedah including the Langkawi Island using the complete control region (CR) segment of the mitochondrial DNA. Standard genetic diversity including nucleotide diversity, haplotype diversity and genetic divergence were calculated. Moderate nucleotide diversity (π = 0.021) was observed which is higher than a previous study on the Penang M. fascicularis population. Twenty-three haplotypes were detected with haplotype diversity, h of 0.936. Haplotype sharing was observed among Langkawi and Perlis macaques indicating historical connection between the island and the mainland. Phylogenetic trees constructed grouped the samples into 4 groups without any obvious populations structuring

Experimental Demonstration of Continuous Electronic Structure Tuning via Strain in Atomically Thin MoS₂

We demonstrate the continuous tuning of the electronic structure of atomically thin MoS₂ on flexible substrates by applying a uniaxial tensile strain. A redshift at a rate of ∼70 meV per percent applied strain for direct gap transitions, and at a rate 1.6 times larger for indirect gap transitions, has been determined by absorption and photoluminescence spectroscopy. Our result, in excellent agreement with first principles calculations, demonstrates the potential of two-dimensional crystals for applications in flexible electronics and optoelectronics

Species-level identification of the blowfly Chrysomya megacephala and other Diptera in China by DNA barcoding

The blowfly Chrysomya megacephala, or oriental latrine fly, is the most common human-associated fly of the oriental and Australasian regions. C. megacephala is of particular interest for its use in forensic entomology and because it is a disease vector. The larvae are economically important as feed for livestock and in traditional Chinese medicine. Identification of adults is straightforward, but larvae and fragments of adults are difficult to identify. We collected C. megacephala, its allies Chrysomya pinguis and Protophormia terraenovae, as well as flies from 11 other species from 52 locations around China, then sequenced 658 base pairs of the COI barcode region from 645 flies of all 14 species, including 208 C. megacephala, as the basis of a COI barcode library for flies in China. While C. megacephala and its closest relative C. pinguis are closely related (mean K2P divergence of 0.022), these species are completely non-overlapping in their barcode divergences, thus demonstrating the utility of the COI barcode region for the identification of C. megacephala. We combined the 208 C. megacephala sequences from China with 98 others from public databases and show that worldwide COI barcode diversity is low, with 70% of all individuals belonging to one of three haplotypes that differ by one or two substitutions from each other, reflecting recent anthropogenic dispersal from its native range in Eurasia.The accepted manuscript in pdf format is listed with the files at the bottom of this page. The presentation of the authors' names and (or) special characters in the title of the manuscript may differ slightly between what is listed on this page and what is listed in the pdf file of the accepted manuscript; that in the pdf file of the accepted manuscript is what was submitted by the author

A formal re-description of the cockroach Hebardina concinna anchored on DNA Barcodes confirms wing polymorphism and identifies morphological characters for field identification.

BACKGROUND: Hebardina concinna is a domestic pest and potential vector of pathogens throughout East and Southeast Asia, yet identification of this species has been difficult due to a lack of diagnostic morphological characters, and to uncertainty in the relationship between macroptyrous (long-winged) and brachypterous (small-winged) morphotypes. In insects male genital structures are typically species-specific and are frequently used to identify species. However, male genital structures in H. concinna had not previously been described, in part due to difficulty in identifying conspecifics. METHODS/PRINCIPAL FINDINGS: We collected 15 putative H. concinna individuals, from Chinese populations, of both wing morphotypes and both sexes and then generated mitochondrial COI (the standard barcode region) and COII sequences from five of these individuals. These confirmed that both morphotypes of both sexes are the same species. We then dissected male genitalia and compared genital structures from macropterous and brachypterous individuals, which we showed to be identical, and present here for the first time a detailed description of H. concinna male genital structures. We also present a complete re-description of the morphological characters of this species, including both wing morphs. CONCLUSIONS/SIGNIFICANCE: This work describes a practical application of DNA barcoding to confirm that putatively polymorphic insects are conspecific and then to identify species-specific characters that can be used in the field to identify individuals and to obviate the delay and cost of returning samples to a laboratory for DNA sequencing

<i>Hebardina concinna</i> specimens collected for morphological study.

<p>Macropterous is defined as tegmen fully developed and extending well beyond the end of abdomen; brachypterous is defined as tegmen just about reaching to the hind margin of the second abdominal tergum. Note that there is no overlap in tegmen length between the two size classes. Individuals marked with an asterisk (*) were selected for DNA barcoding.</p><p><i>Hebardina concinna</i> specimens collected for morphological study.</p

Dotplots of Tegmen length vs Pronotum length and body length in <i>Hebardina concinna</i>.

<p>These correlated characters form statistically non-overlapping groups in macropterous vs. brachypterous individuals. A. Tegmen length vs pronotum length; B. Tegmen length vs body length. Remarks: Triangle for male macropterous; circle for female macropterous; box for male brachypterous; star for female brachypterous.</p

Male genital structures of <i>Hebardina concinna</i>.

<p>A. left phallomere, dorsal view. B. left phallomere, ventral view. C. right phallomere, dorsal view. D. right phallomere, ventral view. (R for right, L for left, v for ventral, d for dorsal).</p

Results of t-tests for quantitative morphology.

<p>There Are Clear and Significant Correlations between Tegmen Length (TL), Pronotum Length (PL), and Body Length (BL). M, Macropterous; B, Brachypterous; Mm, Macropterous Male; Mf, Macropterous Female; Bm, Brachypterous Male; Bf, Brachypterous Female.</p><p>Results of t-tests for quantitative morphology.</p

Distance matrix/neighbor joining phylogenetic tree based on 306 bp of aligned cockroach COII nucleotide sequences.

<p>The maximum likelihood tree was topologically identical, although with differing branch lengths. Numbers on branches represent support from 1000 non-parametric bootstrap replicates for distance matrix-NJ analysis and maximum likelihood analysis, respectively. Missing numbers indicate branches with less than 50% support. This analysis clearly supports grouping of the five <i>H. concina</i> individuals as a single species.</p