Interspecific Genetic Variation Research Articles

New species, redescriptions and new records of deep-sea brittle stars (Echinodermata: Ophiuroidea) from the South China Sea, an integrated morphological and molecular approach

Deep-sea ophiuroids were collected by the manned submersible ‘Shenhaiyongshi’ from the South China Sea at depths of 500–3550 m, in 2017 to 2020. A total of 18 species were identified, including three new species and eight new records, increasing the total number of species known from the South China Sea to 304. Most of the ophiuroids recorded from the South China Sea were found in shallow waters (77.9%) and a few of them occurred only in deep water (20.4%). Three new species are described as Ophiacantha aster sp. nov., Ophiomoeris petalis sp. nov. and Ophiopristis shenhaiyongshii sp. nov. We provide comprehensive descriptions of morphological features, including characteristics of the arm skeletons, and a phylogenetic analysis based on COI and 16S sequences. Overall intraspecific and interspecific genetic distance variations among the families found in this study were 0.5% to 2.47% and 1.16% to 44.16%, respectively, along the South Pacific region to the South China Sea. Our phylogenetic analysis suggested that COI partial genes resolved the interspecies complexity in the class Ophiuroidea better than 16S partial genes. The order Euryalida had low interspecies genetic distance variation within the class Ophiuroidea. The present study suggests a high probability that species of Asteroschema and Gorgonocephalus are more widely spread around the Indo-Pacific region than previously expected.

Local ecological divergence of two closely related stag beetles based on genetic, morphological, and environmental analyses.

The process of phenotypic adaptation to the environments is widely recognized. However, comprehensive studies integrating phylogenetic, phenotypic, and ecological approaches to assess this process are scarce. Our study aims to assess whether local adaptation may explain intraspecific differentiation by quantifying multidimensional differences among populations in closely related lucanid species, Platycerus delicatulus and Platycerus kawadai, which are endemic saproxylic beetles in Japan. First, we determined intraspecific analysis units based on nuclear and mitochondrial gene analyses of Platycerus delicatulus and Platycerus kawadai under sympatric and allopatric conditions. Then, we compared differences in morphology and environmental niche between populations (analysis units) within species. We examined the relationship between morphology and environmental niche via geographic distance. P. kawadai was subdivided into the “No introgression” and “Introgression” populations based on mitochondrial COI gene – nuclear ITS region discordance. P. delicatulus was subdivided into “Allopatric” and “Sympatric” populations. Body length differed significantly among the populations of each species. For P. delicatulus, character displacement was suggested. For P. kawadai, the morphological difference was likely caused by geographic distance or genetic divergence rather than environmental differences. The finding showed that the observed mitochondrial–nuclear discordance is likely due to historical mitochondrial introgression following a range of expansion. Our results show that morphological variation among populations of P. delicatulus and P. kawadai reflects an ecological adaptation process based on interspecific interactions, geographic distance, or genetic divergence. Our results will deepen understanding of ecological specialization processes across the distribution and adaptation of species in natural systems.

The relevance of genetic structure in ecotype designation and conservation management.

The concept of ecotypes is complex, partly because of its interdisciplinary nature, but the idea is intrinsically valuable for evolutionary biology and applied conservation. The complex nature of ecotypes has spurred some confusion and inconsistencies in the literature, thereby limiting broader theoretical development and practical application. We provide suggestions for how incorporating genetic analyses can ease confusion and help define ecotypes. We approach this by systematically reviewing 112 publications across taxa that simultaneously mention the terms ecotype, conservation and management, to examine the current use of the term in the context of conservation and management. We found that most ecotype studies involve fish, mammals and plants with a focus on habitat use, which at 60% was the most common criterion used for categorization of ecotypes. Only 53% of the studies incorporated genetic analyses, and major discrepancies in available genomic resources among taxa could have contributed to confusion about the role of genetic structure in delineating ecotypes. Our results show that the rapid advances in genetic methods, also for nonmodel organisms, can help clarify the spatiotemporal distribution of adaptive and neutral genetic variation and their relevance to ecotype designations. Genetic analyses can offer empirical support for the ecotype concept and provide a timely measure of evolutionary potential, especially in changing environmental conditions. Genetic variation that is often difficult to detect, including polygenic traits influenced by small contributions from several genes, can be vital for adaptation to rapidly changing environments. Emerging ecotypes may signal speciation in progress, and findings from genome‐enabled organisms can help clarify important selective factors driving ecotype development and persistence, and thereby improve preservation of interspecific genetic diversity. Incorporation of genetic analyses in ecotype studies will help connect evolutionary biology and applied conservation, including that of problematic groups such as natural hybrid organisms and urban or anthropogenic ecotypes.

Identification and Distribution of Wedge Clams (Donacidae: Bivalvia) in Thailand by Geometric Morphometric and Molecular Analysis.

The phylogenetic relationship of living Thai Donacidae was herein studied. Two methodologies, geometric morphometrics (GM) and genetic analysis of COI sequences, were combined and applied to identify the valid taxa and explain biodiversity and the distribution pattern in this family. A total of 587 living specimens were tested to analyze the shape and size patterns by Elliptic Fourier Analysis (EFA). Shell identification and GenBank sequences were added to construct the phylogenetic relationship and haplotype network. Centroid size was used to identify the specimens to the subgenus level. Donax (Hecuba) scortum, was easily distinguished from other species by Principal Component analysis (PCA) of shell size and shape. Donax (Dentilatona) incarnatus and Donax (Deltachion) semisulcatus semisulcatus were identified using Canonical Variates Analysis (CVA). Pairwise comparison of EFA was used for species level recognition, particularly shape overlap was observed for medium and small shell size. Based on genetic distance and haplotype network of COI sequences, Donax (Latona) faba and D. (Latona) solidus could be grouped in the same clade. Intraspecific and interspecific genetic data variation of some common species in different geographical localities of Thailand was observed. Three distribution patterns of Donax species were observed along the two-marine system of Thailand.

التعرف على الفربيون الصباري "Euphorbia Royleana" المدرج ضمن اتفاقية الاتجار الدولي بأنواع النباتات والحيوانات البرية المهددة بالانقراض "CITES" من خلال استخدام تقنية الترميز الشريطي للحمض النووي: وجه جديد لعلوم الأدلة الجنائية للحياة البرية

Disorganized and chaotic collection of the Euphorbia plant species from the wild is one of the major reasons for its endangered status. According to CITES, the trade in Euphorbia royleana species is prohibited under Appendix II. However, the trade continues unabated as current identification methods do not discriminate between closely related species. In the present study, a DNA barcoding method has been used to establish inter- and intra-specific divergences of both matK and rbcL regions by using pairwise genetic distance measurement methods for evaluating the maximum barcoding gap. The matk and rbcL yielded a 100% amplification and sequencing success rate to distinguish closely related species of Euphorbia royleana unambiguously. The matk and rbcL showed average interspecific genetic distance divergence values of 0.031and 0.015, respectively. The maximum number of species-specific SNPs was observed in matK sequences at seven consecutive sites, which could distinguish Euphorbia royleana from closely related species. The best candidate barcoding region to identify Euphorbia royleana was found to be matK with a single-locus barcoding approach. Furthermore, the species discrimination method was developed with the help of species-specific SNPs derived from the matK barcoding region to accurately authenticate Euphorbia royleana, and it provided 100% species resolution

The Strait of Gibraltar is an ineffective palaeogeographic barrier for some flightless darkling beetles (Coleoptera: Tenebrionidae:Pimelia)

AbstractThe geographic distribution of a species is shaped by its biology and by environmental and palaeogeographic factors that interact at different spatial-temporal scales, which leads to distributions and diversification patterns observed between and within lineages. The darkling beetle genus Pimelia has been diversifying for more than 31.2 Mya showing different colonization patterns after the opening of the Gibraltar Strait 5 Mya. Three of the 14 subgenera of Pimelia have populations on both sides of the Strait. Through extensive sampling and the analysis of three molecular markers, we determine levels of intra- and interspecific genetic variation, identify evolutionary lineages in subgenera, estimate their temporal origin and distribution ranges and discuss the historical basis for the geographic and diversification patterns of Pimelia around the Strait. This single geographical feature acted both as a barrier and as a dispersal route for different Pimelia species. The Strait has represented a strong barrier for the subgenus Magrebmelia since the Middle Miocene. However, the subgenera Amblyptera and Amblypteraca share repetitive signatures of post-Messinian colonization across the Strait, possibly driven by stochastic or ‘catastrophic’ events such as tsunamis. Our demographic analyses support Wallace’s hypothesis on insect dispersal stochasticity. Some taxonomic changes, including the designation of a lectotype for Pimelia maura, are also proposed.

Molecular epidemiology of Paracoccidiodes spp. recovered from patients with paracoccidioidomycosis in a teaching hospital from Minas Gerais State of Brazil.

IntroductionParacoccidioidomycosis (PCM) is caused by several species of the Paracoccidioides genus which can be differentiated by interspecific genetic variations, morphology and geographic distribution. Intraspecific variability correlation with clinical and epidemiological aspects of these species still remains unclear. This study aimed to sequence the loci GP43, exon 2 and ARF of 23 clinical isolates of Paracoccidioides spp. from patients in the Southeast Region of Brazil.Methodology and main findingsGenBank was used to compare the present (23) with previous described sequences (151) that included ARF and GP43. It was identified a high polymorphism rate among the 23 isolates in comparison to the other 151. Among the isolates, 22 (95.66%) were S1/P. brasiliensis and 1 (4.34%) was identified as PS2/P. americana. A total of 45 haplotypes were found as follows: 19 from S1/P. brasiliensis (13 from the present study), 15 from P. lutzii, 6 from PS2/P. americana (1 from the present study), 3 from PS3/P. restrepiensis and 2 from PS4/P. venezuelensis. Moreover, exclusive haplotypes according to clinical origin and geographical area were found. S1/P. brasiliensis (HD = 0.655 and K = 4.613) and P. lutzii (HD = 0.649 and K = 2.906) presented the highest rate of polymorphism among all species, from which 12 isolates of the present study were clustered within S1b/P. brasiliensis. The GP43 locus showed a higher variability and was found to be the main reason for the species differentiation.ConclusionsThe results herein decribed show a high intraspecific genetic variability among S1/P. brasiliensis isolates and confirm the predominance of this species in the Southeast region of Brazil. The finding of exclusive haplotypes according to clinical origin and geographical area would suggest correlation between the molecular profile with the clinical form and geographic origin of patients with PCM.

Spatial and host related genomic variation in partially sympatric cactophagous moth species.

Surveys of patterns of genetic variation in natural sympatric and allopatric populations of recently diverged species are necessary to understand the processes driving intra- and interspecific diversification. The South American moths Cactoblastis cactorum, Cactoblastis doddi and Cactoblastis bucyrus are specialized in the use of cacti as host plants. These species have partially different geographic ranges and differ in patterns of host plant use. However, there are areas that overlap, particularly, in northwestern Argentina, where they are sympatric. Using a combination of genome-wide SNPs and mitochondrial data we assessed intra and interspecific genetic variation and investigated the relative roles of geography and host plants on genetic divergence. We also searched for genetic footprints of hybridization between species. We identified three well delimited species and detected signs of hybridization in the area of sympatry. Our results supported a hypothetical scenario of allopatric speciation in the generalist C.cactorum and genetic interchange during secondary geographic contact with the pair of specialists C.bucyrus and C.doddi that probably speciated sympatrically. In both cases, adaptation to new host plants probably played an important role in speciation. The results also suggested the interplay of geography and host plant use as drivers of divergence and limiting gene flow at intra and interspecific levels.

Stable climate corridors promote gene flow in the Cape sand snake species complex (Psammophiidae)

AbstractClimate shifts during the Quaternary Period have driven changes in regional range dynamics for many species, influencing population structure of species and in some cases promoting speciation. Within southern Africa, the psammophine snakes Psammophis trinasalis and P. namibensis were historically considered subspecies of P. leightoni but were elevated to species rank based on ecological differences. Preliminary phylogenetic analyses suggested intraspecific, not interspecific genetic variation between these taxa, but this finding was based on very limited data and could not be confirmed. To assess the level of genetic differentiation within the P. leightoni species complex, we explored the evolutionary history of these snakes by combining phylogenetic analyses, species distribution modelling and an examination of morphology. We generated a comprehensive, multi‐gene phylogeny for Psammophis that included wider geographic sampling of the three species in the complex. Using this phylogeny, Bayesian and distance‐based species delimitation analyses showed intraspecific, not interspecific divergences between taxa in the complex, suggesting that they collectively represent a single taxon. Furthermore, non‐metric multidimensional scaling analysis of scalation characters showed no differences between the species. Moreover, palaeo‐modelling at three time periods since the last interglacial period suggest that there have been varying levels of connectivity between these taxa, which has likely facilitated gene flow between them. Given the evidence, we propose that the P. leightoni complex represents a single species and therefore formally synonymise the three species.

Barcoding of South African forest‐dwelling snails (Mollusca: Gastropoda) reveals widespread cryptic diversity

AbstractSouth Africa harbors a rich and diverse terrestrial snail fauna. Despite their importance in ecosystem functioning and structure, their alpha taxonomic diversity is poorly understood, and most groups have not been the subject of molecular systematic scrutiny. During the present study, we used the mitochondrial cytochrome c oxidase subunit I (COI) locus to start a DNA barcode reference library, to examine intra‐ and interspecific genetic divergence, and to explore the presence of cryptic diversity among terrestrial gastropods from forested regions in the country. We generated 399 COI barcodes comprising 70 morphospecies in 26 genera and 15 families, representing nearly 10% of the described gastropod diversity in South Africa. Our results showed a substantial overlap between mean intraspecific and interspecific genetic variation and no barcoding gap. Three species delimitation methods—Poisson Tree Processes (PTP), Refined Single Linkage (RESL) algorithm in Barcode of Life Data Systems, and the Automatic Barcode Gap Discovery (ABGD)—applied to selected widespread species retrieved incongruent operational taxonomic units (OTUs). These results, coupled with high intraspecific variation, suggested cryptic diversity among several terrestrial gastropod genera in the country. We further demonstrated that DNA barcoding analysis holds the potential for highlighting cryptic lineages in snails and for revealing taxa in need of taxonomic revision. We recommend that future taxonomic studies of South African terrestrial snails incorporate multiple sources of information for species delimitation.

DNA barcoding evaluation of geophytes: Comparative efficiency of three barcode loci for Anemone (Ranunculaceae) and Gladiolus (Iridaceae)

Anemone and Gladiolus are economically important geophyte genera due to their usage as ornamental plants. However, species identification is still under debate. Recently, DNA barcoding has become an efficient alternative tool for species identification. Here, candidate DNA barcode regions, rbcL, rpoB, and trnH-psbA were analyzed as potential DNA barcodes in 248 accessions of these geophyte genera using pair-wise distance-based, sequence similarity (best match and best close match) and tree-based (neighbor joining, maximum likelihood, and Bayesian tree) methods. Among all barcoding single or combination loci, trnH-psbA had the highest interspecific genetic variation in Anemone, and the region was the most promising candidate for barcoding gap analysis. However, none of the barcode regions showed a clear barcode gap for identification. The internal spacer, trnH-psbA, also showed the highest correct identification rate in Anemone, while rbcL showed the best performance in Gladiolus using the sequence similarity method. In the single barcode approach, rpoB had the best discrimination rate for both genera when using tree-based methods. Therefore, we recommend a tree-based method because it was clear that all tested loci had specific performance degrees depending on the methods. This is the first application of rpoB in terms of DNA barcoding criteria in geophyte taxa.

Species Diversity and Phylogenetic Relationships of Olive Lace Bugs (Hemiptera: Tingidae) Found in South Africa.

Simple SummaryOlive lace bugs feed on wild and cultivated Olea europaea, causing a negative impact on plant vitality and development. These insects are known to affect olive orchards in South Africa, the country where most of the olive and olive products on the continent are produced. However, the diversity of species of these pests is not clear. Morphological analysis and DNA barcoding showed the presence of Cysteochila lineata, Plerochila australis, Neoplerochila paliatseasi and Neoplerochila sp. Further analyses of genetic divergence and phylogenetic clustering in 30 species in 18 genera of Tingidae using new and publicly available DNA barcodes showed that the majority of sequences deposited on BOLD Systems were correctly assigned to species. The complete mitochondrial genomes of the four species found in South Africa were sequenced to assess their phylogenetic position within Tingidae. The four olive lace bugs formed one cluster of species, and the genus Cysteochila was not monophyletic as C. lineata grouped with the other three olive lace bugs but C. chiniana was placed in a different cluster. This result suggests that lace bug species that feed on olive trees may have a common ancestor and calls for further research on potential adaptations to O. europaea.Olive lace bugs (Hemiptera: Tingidae) are small sap-sucking insects that feed on wild and cultivated Olea europaea. The diversity of olive lace bug species in South Africa, the most important olive producer on the continent, has been incompletely surveyed. Adult specimens were collected in the Western Cape province for morphological and DNA-based species identification, and sequencing of complete mitogenomes. Cysteochila lineata, Plerochila australis, Neoplerochila paliatseasi and Neoplerochila sp. were found at 12 sites. Intra- and interspecific genetic divergences and phylogenetic clustering in 30 species in 18 genera of Tingidae using new and publicly available DNA barcodes showed high levels of congruity between taxonomic and genetic data. The phylogenetic position of the four species found in South Africa was inferred using new and available mitogenomes of Tingidae. Notably, olive lace bugs formed a cluster of closely related species. However, Cysteochila was non-monophyletic as C. lineata was recovered as a sister species to P. australis whereas Cysteochila chiniana, the other representative of the genus, was grouped with Trachypeplus jacobsoni and Tingis cardui in a different cluster. This result suggests that feeding on O. europaea may have a common origin in Tingidae and warrants future research on potential evolutionary adaptations of olive lace bugs to this plant host.

Retrotransposons and multilocus sequence analysis reveals diversity and genetic variability in endophytic fungi-associated with Serjania laruotteana Cambess.

The composition of endophytic communities is dynamic and demonstrates host specificity; besides, they have great intra- and interspecific genetic variability. In this work, we isolated leaf endophytic fungi from Serjania laruotteana, identify them using multilocus analysis, and evaluate the genetic variability using IRAP (inter-retrotransposon amplified polymorphism) and REMAP (retrotransposon-microssatellite amplified polymorphism). A total of 261 fungi were isolated and 58 were identified. Multilocus phylogenetic analysis using the partial sequences from the ITS1-5.8S-ITS2 regions, elongation factor 1-alpha, β-tubulin, actin, glyceraldehyde-3-phosphate dehydrogenase, and calmodulin genes identify that most strains belonged to the Colletotrichum and Diaporthe genera, other isolated genera were Xylaria, Phyllosticta, Muyocopron, Fusarium, Nemania, Plectosphaerella, Corynespora, Bipolaris, and Curvularia. The IRAP and REMAP analyzes were performed with Colletotrichum and Diaporthe genera and showed 100% of polymorphism and high intra- and interspecific variability. This is the first report of the diversity of endophytic fungi from S. laruotteana. In addition, it demonstrated that the IRAP and REMAP can be used to distinguish morphologically similar lineages, revealing differences even strains of the same species.

Molecular taxonomy of Korean Cafius Stephens, 1829 (Coleoptera: Staphylinidae: Staphylininae) with description of a new species

A species delimitation study of Korean CafiusStephens, 1829 using molecular characters (COI and 28S) is presented. Six coastal species are recognized, one of which is described as Cafius calculosus Lee & Ahn sp. nov. in the intertidal zone of the southern part of the Korean peninsula based on morphological and molecular characters. The new species is closely related and very similar to C. mimulus (Sharp, 1874). Interspecific genetic divergence of COI using uncorrected p-distance ranged from 10.77% to 18.78%, while intraspecific divergence ranged from 0.00% to 2.51% among six Korean Cafius species. All six species were each strongly supported as a single lineage using COI and 28S on both neighbor-joining and parsimony trees. A description, habitus photograph and diagnostic characters of the new species and a key to the species of Korean Cafius are provided to facilitate identification.

The hidden diversity of the genus Lyurella Derzhavin, 1939 (Crustacea: Amphipoda: Crangonyctidae): four new species from the subterranean habitats of the northwestern Caucasus, Russia.

Four new species of the Palaearctic crangonyctid amphipod genus Lyurella Derzhavin, 1939 (Crustacea: Amphipoda: Crangonyctidae), L. mikhailovi sp. n., L. fanagorica sp. n., L. fontinalis sp. n. and L. asheensis sp. n., are described based on an integrative approach from the subterranean habitats of the southwestern foothills of the Greater Caucasian Ridge (the north-eastern Black Sea coast). Despite the relative proximity of the habitats, the interspecific genetic divergence (by COI mtDNA gene marker) between the newly outlined Caucasian species of the genus varied from 11 to 21%, demonstrating a long-term isolation and lack of gene flow for at least 37Mya, starting from the Pliocene. The lowest genetic divergence between L. shepsiensis Sidorov, 2015 and L. asheensis sp. n., estimated as 4%, is also considered species-specific due to the presence of distinct morphological differences. We discuss the phylogeny, morphology, and distribution and provide a key for all known species of Lyurella. DNA barcoding data for all species, including the type species of the genus, Lyurella hyrcana Derzhavin, 1939, are presented for the first time.

Description of the growth hormone gene of the Australasian snapper, Chrysophrys auratus, and associated intra- and interspecific genetic variation.

The growth hormone (GH) gene of the marine teleost, the Australasian snapper (Chrysophrys auratus), was identified and characterized from the reference genome showing it was approximately 5577 bp in length and consisted of six exons and five introns. Large polymorphic repeat regions were found in the first and third introns, and putative transcription factor binding sites were identified. Phylogenetic analysis of the GH genes of perciform fish showed largely conserved coding regions and highly variable noncoding regions among species. Despite some exon sequence variation and an amino acid deletion identified between C. auratus and its sister species Chrysophrys/Pagrus major, the amino acid sequences and putative secondary structures were largely conserved across the Sparidae. A population-level assessment of 99 samples caught at five separate coastal locations in New Zealand revealed six variable alleles at the intron 1 site of the C. auratus GH gene. A population genetic analysis suggested that C. auratus from the five sample locations were largely panmictic, with no evidence for departure from the Hardy-Weinberg equilibrium, and have a high level of heterozygosity. Overall these results suggest that the GH gene is largely conserved across the coding regions, but some variability could be detected.

Molecular Characterization of Copy’s Frog Hydrophylax Leptoglossa Based on 16s rRNA Gene

Copy’s frog, commonly observed in Bangladesh, is ecologically important for evergreen forest. Sample was collected from Satchari National park, Hobigonj, Sylhet. Attempts were made to combine morphological and molecular techniques for identification and analysis of evolutionary relation of Copy’s frog with anuran species. Morphological identification of Hydrophylax sp. was conducted based on distinguishing characteristics of the body and different body measurement parameter. The species was identified morphologically as Hydrophylax leptoglossa based on the taxonomic key of finger toes and formula was 3>1>4>2. Simultaneously genomic DNA was isolated using CTAB extraction method. The 16S rRNA gene was amplified from the genomic DNA by polymerase chain reaction method using the pair of universal primers. Amplified product was a 308 bp fragment that generated AT/GC ratio of 1.08% once sequenced. In the present study comparative analysis of intraspecific and interspecific variation was conducted based on nucleotide sequence of 16S rRNA gene collected from GenBank. The intraspecific variation compares between Southeast Asia and Bangladesh was 1.29% for 16S rRNA gene. The interspecific genetic divergence was studied between H. leptoglossa and H. tytleri was observed 14.29%. The nucleotide sequence of the present study will be used as DNA barcode for that particular individual collected from Sylhet, Bangladesh. Furthermore, a molecular phylogenetic tree was constructed, where all the anuran species from a monophyletic group. Four species of Hydrophylax form monophyletic group and is consistent with relation based on morphology. Bangladesh J. Zool. 49(1): 105-115, 2021

Assessment of genetic diversity of Musa species accessions with variable genomes using ISSR and SCoT markers

Assessing the effectiveness of different molecular markers is essential for identification of appropriate ones for crop improvement and conservation, hence, inter-simple sequence repeat (ISSR) and start codon targeted (SCoT) markers were used for this study. Sixty-six accessions with different genomes obtained from International Transit Center, Belgium, were used for DNA extraction, amplification with ISSR and SCoT markers and agarose gel electrophoresis. The reproducible bands were scored for analyses. We identified high allelic richness of 299 (ISSR) and 326 (SCoT). Polymorphic information contents (ISSR: 0.9225; SCoT: 0.9421) were high but SCoT exhibited higher level of informativeness. The two markers demonstrated high percentage polymorphic loci (ISSR: 91.21–100%; SCoT: 96.97–100%). Other genetic indicators including effective number of alleles, Nei’s genetic diversity, and Shannon information index were higher in SCoT and further elucidated the usefulness of the markers. Intraspecific genetic diversity, interspecific genetic diversity, coefficient of gene differentiation and level of gene flow revealed extensive gene flow and larger variability within the accessions. Both ISSR and SCoT grouped the accessions via dendrogram, biplot and structure analyses. Though the two marker systems varied in their informativeness, they demonstrated high effectiveness in resolving genetic diversity (GD) of the different accessions, with higher efficiency in SCoT markers. Due to higher GD indices exhibited by SCoT, AS is the most genetically endowed one. Our study showed that SCoT markers are more informative than ISSR for GD exploration, assessment and cluster resolution of Musa species, thereby revealing the potential of SCoT markers for improved breeding and conservation.

Integrative taxonomy uncovers a new Culicoides (Diptera: Ceratopogonidae) biting midge species from Thailand

Fully understanding biodiversity often requires an integrated approach especially for small insects because species diagnostic morphological characters are limited. In this study, morphological characters and DNA barcodes were used to examine previously recognized genetically divergent lineages detected in the biting midge, Culicoides arakawae (Arakawa), from Thailand. Morphological examinations revealed that specimens belonging to one lineage are morphologically different from C. arakawae in shape of the paramere in males, and in the leg color pattern of both sexes. Therefore, a formal description is provided for this new species, Culicoides mahasarakhamense sp. nov. Based on morphological characters including a large and shallow palpal pit, one sac like spermatheca and male with parameres bent at base with large basal knob, the new species was assigned into the subgenus Meijerehelea Wirth and Hubert. Morphological differentiation including wing pattern and shape of spermatheca of the new species are discussed and compared with other members of this subgenus. Mitochondrial cytochrome c oxidase I sequence analysis indicated that this new species is different from other members of the subgenus Meijerehelea with minimum interspecific genetic divergence of 3.92%. Automatic Barcode Gap Discovery species delimitation analysis also supported the recognition of a new species. Phylogenetic analyses revealed that the new species is closely related to C. arakawae, consistent with morphological similarity of these species. Results of this study highlight the necessity of using integrated approach for Culicoides taxonomy.

Role of Geographical Gaps in the Western Ghats in Shaping Intra- and Interspecific Genetic Diversity

Role of Geographical Gaps in the Western Ghats in Shaping Intra- and Interspecific Genetic Diversity