Genetic Distance Values Research Articles

Revealing the Genetic Differentiation of Rattus norvegicus (Berkenhout 1769) Populations by Analyzing Two Mitochondrial Markers

Rattus norvegicus (Brown rat) has a great importance for public health and economy because it lives in close association with human populations. However, molecular systematic studies on global populations of R. norvegicus are very few. In this study, sequences obtained from Europe, Asia, Africa, and America regions were analyzed using mitochondrial Cytochrome-b and Cytochrome oxidase-I gene regions and genetic differentiation levels between these populations were revealed. Accordingly, samples belonging to the studied populations did not split in Bayesian Inference trees and Median-joining networks; these samples also formed common haplotypes, and mean genetic distance and fixation index values were generally low. The results of the study showed that gene flow between these populations may be continuing due to the transportation activity by humans.

Forensic characteristics of 38 Y-STR loci in the Hui population from Shaanxi Province, Northwest China

In this study, we genotyped 939 unrelated healthy individuals to investigate the genetic polymorphisms of 38 Y chromosome short tandem repeats(Y-STRs) loci included in the Yfiler™ Platinum kit in the Hui population of Shaanxi Province. Comprehensive population comparisons were performed using analysis of molecular variance(AMOVA), multidimensional scaling(MDS), and molecular evolutionary genetics analysis(MEGA) to explore population relationships. The allele frequencies of the single-copy loci ranged from 0.001 to 0.940 (DYS645), while those of the multi-copy loci ranged from 0.001 to 0.138 (DYS527). The highest genetic diversity (GD) value was observed for DYS385 (0.9723), and the lowest for DYS645 (0.1138). A total of 849 distinct haplotypes were identified among the 939 Hui individuals, with 808 (95.2 %) being unique. Haplotype diversity (HD), haplotype match probability, and discriminatory power (DC) in the Shaanxi Hui population were 0.9996, 0.0015, and 0.9041, respectively. Interpopulation comparisons based on Rst genetic distance values, phylogenetic trees, and MDS indicated that the Shaanxi Hui population has a close genetic relationship with the Ningxia Hui, Qinghai Hui, Xinjiang Hui, and Yunnan Hui populations. The population genetic stratification largely coincides with geographic distribution and language families. Our study revealed that the 38 Y-STR loci exhibit high genetic polymorphisms in the Hui population from Shaanxi Province.

Population dynamics and genetic isolation in the Central Himalayan region: insights from Sikkim population, India.

India's rich diversity encompasses individuals from varied geographical, cultural, and ethnic backgrounds. In the field of population genetics, comprehending the genetic diversity across distinct populations plays a crucial role. This study presents significant findings from genetic data obtained from the Sikkimese population of India. Autosomal markers were crucial for evaluating forensic parameters, with a combined paternity index of 1 × 109. Notably, Penta E emerged as a distinguishing marker for individual identification in the Sikkim population. Fst genetic distance values revealed insights into genetic isolation among different groups, enhancing our understanding of population dynamics in the central Himalayan region. The NJ-based phylogenetic tree highlighted close genetic relationships, of the Sikkim population with the Nepalese population surrounding neighbouring Himalayan populations providing glimpses into common ancestry. In summary, this study contributes valuable data to population genetics and underscores the importance of genetic variation in comprehending population dynamics and forensic applications.

Genetic Diversity and Profile of Red Algae Pterocladiella capillacea (Gelidiales, Rhodophyta) along the Coast of China

Red algae Pterocladiella capillacea off the coast of China were investigated for genetic diversity. With 176 samples categorized into six populations based on concatenated rbcL and cox1 sequences, the results rang warning bells for the genetic diversity of Pterocladiella capillacea along the Chinese coastline: (1) a good diversity of haplotype (Hd > 0.5) in Naozhou and Hui’an populations situated along the southern coast of China, but highest in the former; (2) less nucleotide diversity in each of the six populations (Pi < 0.005); (3) genetic differentiation occurred between the north population in Changdao and the two southern grown populations in Nan’ao, and Naozhou. To identify molecular markers, an MP phylogenetic tree was used to illustrate genetic profiles in detail, with 161 concatenated sequences clustered into four branches: Changdao (north), Nan’ao (south), Naozhou (south), and the remaining regions (middle). The Fst value for each of Changdao, Nan’ao, and Naozhou was greater than 0.5, which denotes that these three populations are genetically different to those growing in the middle coast. Moreover, a 30-haplotype-based median-joining network corroborated this genetic differentiation, though variations between all the investigated populations were not very high due to the relatively smaller values of genetic distance between the six (Dxy < 0.01). Overall, red algae P. capillacea in Chinese coastal seawater showed a higher haplotype diversity and lower nucleotide diversity. Such a genetic profile indicates that both natural random genetic drift and interference from human activities have possibly affected the distribution of gene frequencies in red algae P. capillacea along the Chinese coastline.

Effectiveness of ISSR markers for detecting genomic variability in <I>Panicum miliaceum</I> L. accessions

Background. Millet is one of the main cereal crops with a wide area of cultivation. Over the past decade, there has been a significant increase in the consumption of millet and its processed products. As a result, the breeding of cultivars with high consumer properties is becoming relevant, requiring knowledge of the genetic diversity of germplasm accessions to identify donors of valuable agronomic traits and select parental forms using ISSR markers.Materials and methods. The analysis with 8 ISSR primers included 21 accessions of Panicum miliaceum L. of various origin from the VIR collection. The DNA of each accession was isolated by the CTAB method, and ISSR analysis was performed in a ­BioRad T100 Thermal Cycler. Statistical processing was made in the DARwin program (version 6.0.21).Results and conclusion. Eight primers were used to amplify 116 fragments, 62 (53.4%) of which turned out to be polymorphic. To assess the effectiveness of the analyzed primers and identify the polymorphism of millet, basic indicators of their informativeness were calculated and assessed by quantifying four marker parameters. Average PIC (0.27–0.36), EMR (1.38–14.5) and MI (0.12–4.87) values were obtained for most ISSR primers. Four ISSR primers had high Rp values (3.52–6.76) and were the most informative for genotyping. The selected ISSR markers were used to assess the genetic variability of the accessions and identify them. The values of genetic distances (GD) were 0.05–0.21. It was shown that four ISSR markers with the best informativeness values provided sufficient polymorphism to assess the genetic diversity of the analyzed P. miliaceum genotypes and could be recommended for identification of the variability in the genome of millet accessions.

Comparative Mitogenome Characterization of Cryptic Asian Seabass (Lates calcarifer) in Captivity within Peninsular Malaysia

Lates calcarifer is one of the most commercial species in the world. Yet, phylogenetic relationships among this cryptic species remain unclear despite its significance in the fishery sector. The first report on bifurcation of captive Lates calcarifer in Peninsular Malaysia (PM) inferred from complete mitochondrial genome was discussed in the present study. Two mitochondrial genomes (mitogenomes) of Lates species were sequenced and assembled. The mitogenome length was 16,627 bp and 16,515 bp for K4 and S15, respectively. The majority of PCGs in both species exhibited the common initiation marker ATG codon and ended with termination marker TAA codon. Also, the incomplete termination codon T/TA was found in both species. Most AT-skew and GC-skew values observed in the protein-coding genes (PCGs) across the two samples were negative. The phylogenetic analysis based on 13 protein-coding genes by Maximum-Likelihood tree displayed two lineages from different regions which were from Myanmar/Indian waters (K4) and Southeast Asia/ Australian waters (S15). The striking genetic distance values between both specimens indicated 13 PCGs were suffering purifying selection. This study offers significant information for future analyses of evolutionary relationships among the numerous and taxonomically puzzling perciform fishes.

Phylogeography of a Widely Distributed Atlantic Species: The Case of the Ghost Crab Ocypode quadrata (Fabricius, 1787) (Decapoda: Brachyura: Ocypodidae)

Ocypode Weber, 1795 (Brachyura: Ocypodidae) is popularly known as ghost crab, and encompasses 21 valid species, including Ocypode quadrata (Fabricius, 1787). This species has wide distribution along the Atlantic coast of America, from the USA (Massachusetts) to Brazil (Rio Grande do Sul), Central America, and Antilles. Such distribution, along with some biological characteristics of its life cycle and the presence of geographic barriers, could lead to genetic structuring. Herein, we evaluate the hypothesis of the presence of geographic barriers using COI and 16S partial gene fragments. The Maximum Likelihood tree suggests the monophyly of O. quadrata, while the values of intraspecific genetic distance along with the star-shaped haplotype network suggested a lack of genetic structure in Brazilian, Panama, and French Guiana populations, probably caused by larval dispersion. USA and Mexico populations may be a new lineage, but we cannot say it with few sequences and with no morphological characters.

Description of a new species of Phoxinus from the Ergene River (Aegean Sea Basin) in Türkiye (Actinopterygii, Leuciscidae)

Phoxinus radeki, a new species, is described from the Ergene River (Aegean Sea Basin). It is distinguished from Phoxinus species in Türkiye and the adjacent area by having the scales of the breast, scaled but separated unscaled area anteriorly, short dark rectangular blotches along the lateral line between the lateral line and belly yellowish in both males and females, body depth dorsal fin origin 16–21% SL, caudal peduncle depth 8–10% SL. Additionally, molecular results demonstrated that the new species differed from its closest congeners with a mean genetic distance value of 3.08% (min. 2.82–max. 3.29) and moderately support values in cytochrome b (Cyt b) gene partial sequences (1064 bp.). Further, the species delimitation analysis identified the new species as a single MOTU independent of other Phoxinus species.

Molecular diversity of Pseudoscorpiones in southern High Appalachian leaf litter.

The Pseudoscorpiones fauna of North America is diverse, but in regions like the southern Appalachian Mountains, they are still poorly documented with respect to their species diversity, distributions and ecology. Several families have been reported from these mountains and neighbouring areas. Here we analyse barcoding data of 136 specimens collected in leaf litter, most of them from high-elevation coniferous forest. We used ASAP as a species delimitation method to obtain an estimation of the number of species present in the region. For this and based on interspecific genetic distance values previously reported in Pseudoscorpions, we considered three different genetic Kimura two-parameter distance thresholds (3%/5%/8%), to produce more or less conservative estimates. These distance thresholds resulted in 64/47/27 distinct potential species representing the families Chthoniidae (33/22/12 species) and Neobisiidae (31/25/15) and at least six different genera within them. The diversity pattern seems to be affected by the Asheville Depression, a major biogeographic barrier in this area, with a higher diversity to the west of this geographic feature, particularly within the family Neobisiidae. The absence of representatives from other families amongst our studied samples may be explained by differences in their ecological requirements and occupation of different microhabitats.

Morphological and molecular data on Pseudozoogonoides ugui Shimazu, 1974 (Digenea: Microphalloidea: Zoogonidae) ex Pseudaspius hakonensis (Günther, 1877) and taxonomic problems in Zoogoninae genera.

New morphological and molecular data were generated for trematodes recovered from the intestines of the fish Pseudaspius hakonensis from two locations in the south of the Russian Far East. Morphologically, these trematodes are identical to Pseudozoogonoides ugui (Microphalloidea: Zoogonidae) from Japan. According to results of phylogenetic analysis based on 28S rDNA sequence data, P. ugui was closely related to Zoogonoides viviparus, and P. subaequiporus appears as a sister taxon to these two species. Genetic distance values, calculated based on both 28S rDNA and ITS2 rDNA, between P. ugui and Z. viviparus represents an interspecific differentiation level. Our results have an ambiguous explanation, indicating that the implication of the presence of one or two compact vitellarial aggregations for the differentiation of Zoogonoides and Pseudozoogonoides should be reconsidered or that our results open up the question of the taxonomical status of trematodes previously denoted as Z. viviparus and P. subaequiporus.

DNA Barcoding of Nematode Parasites Infecting Ompok bimaculatus and Nemacheilus anguilla From Barvi Reservoir, Maharashtra

In the present study, the DNA barcoding of the nematode parasite infecting Ompok bimaculatus and Nemacheilus anguilla fish species was carried out in Barvi Reservoir, Maharashtra. To ascertain the taxonomic status of these nematode parasites, an 18S gene marker was used. Accurate identification of fish parasites is essential to formulate preventive strategies and to study host–environment relations. The present study did barcoding of the nematode parasites of the fishes caught from the Barvi Reservoir using the nuclear 18S rDNA (SSU) sequence. The nuclear 18S rDNA (SSU) was amplified into two overlapping amplicons and sequenced to identify the species based on the sequence similarity with the NCBI GenBank database. The present study sequences (both fragments) showed 98% similarity with the species of Eustrongylides. The average genetic distance value between the present study sample and species of Eustrongylides was 0.003. In the phylogenetic tree also, the sequence was clustered with the species of Eustrongylides with significant bootstrap values. The present study identified the nematode parasite of the fish caught from the Barvi Reservoir, as species of Eustrongylides. The species‐level identification could not be possible due to the insufficient/lack of reference sequences in the database. It indicates the knowledge gap concerning the species‐specific molecular markers for nematode parasites of the fish.

Genetic Diversity of West African Honey Bee (Apis ‎mellifera adansonii Latreille, 1804) from Rural and Urban ‎Areas of ‎Kwara State, North-Central Nigeria

Over one third of the world’s crops– including fruits, vegetables, nuts, spices, and oilseed–‎require insect pollination, and human reliance on ‎pollination services by honey bees (Apis ‎mellifera) to promote these crops continues to rise due to increasing demands from growing ‎human ‎populations. Identifying the effects of urbanization on genetic diversity on this ‎pollinating insect is important in the field of bioscience. This study aimed to investigate genetic diversity of A. mellifera in Kwara State, Nigeria, using the random amplified polymorphic DNA (RAPD) marker. ‎Thirty honey bees ‎were simultaneously collected from both rural and urban regions in ‎Kwara state, Nigeria. Samples were morphologically identified using ‎standard methods, ‎genomic DNA isolated and amplified using five RAPD primers. Data collected were ‎analysed using PyElph, ‎ARLEQUIN, and GeneAlEx version 6.501 software. The results ‎showed that the DNA fragment sizes produced per primer varied from 200 to ‎‎3000 bp. Percentages of polymorphic loci amplified by each primer varied from 17.33 to 33.33%. ‎Analysis of unbiased Nei genetic ‎distance values showed that Agbede (rural) and Adewole ‎‎(urban) showed the highest value of unbiased genetic distance (0.073), while ‎Amoyo ‎‎(rural) to Idofian (urban) exhibited the lowest value (0.027). Dendrogram analysis revealed ‎genetically close relationships among the sampled ‎A. mellifera‎ populations. The low level of genetic ‎polymorphisms observed among the honey bee populations in the two ‎regions ‎indicated that there is genetic relatedness among them. This study concluded that RAPD ‎marker is a useful method for ‎understanding population genetic structure of the African honey ‎bees. These results can be used as baseline information for future genetic ‎diversity ‎assessment of honey bees in Nigeria with larger samples. It is therefore recommended that ‎there is a need to safeguard the genetic ‎diversity of A. mellifera‎ to prevent extinction or ‎gradual loss of diversity‎‎‎.

Genetic Analysis Reveals Relationships Among Populations of Puccinia striiformis f. sp. tritici from Shaanxi-Gansu-Ningxia-Xinjiang of Northwestern and Sichuan-Yunnan of Southwestern China.

Wheat stripe rust, caused by Puccinia striiformis f. sp. tritici (Pst), is one of the most destructive diseases worldwide. In China, wheat stripe rust generally occurs in the northwestern and southwestern regions; however, the genetic relationships of Pst populations between these regions are largely unclear. To determine the population structure and potential migration route in these regions, 235 isolates collected from Xinjiang (XJ), Gansu (GS), Ningxia (NX), Shaanxi (SX), Sichuan (SC), and Yunnan (YN) provinces in 2021 and 2022 were phenotyped using two sets of Pst differentials and genotyped using 20 competitive allele-specific PCR-single nucleotide polymorphism (KASP-SNP) markers. The phenotype tests indicated that CYR34, CYR32, and CYR33 were the predominant races with different occurrence frequencies in different regions and years. Genotypic analysis revealed that a total of 183 multilocus genotypes were identified, and the genetic diversity in the YN subpopulation was the highest. The genetic background in the SX subpopulation was similar to that in the GS and NX subpopulations, and the genetic background in the YN subpopulation was similar to that in the SC and SX subpopulations. A high level of gene flow (Nm) was found between the SX and GS, SX and NX, GS and NX, and SC and YN subpopulations, suggesting the migration of Pst among these regions, while a small amount of Nm existed between the SX and SC subpopulations. SC may serve as a bridge connecting Pst subpopulations between the northwestern provinces (SX, GS, and NX) and the southwestern provinces (SC and YN). With a relatively high genetic distance and low Nm values compared with other Pst subpopulations, XJ is considered a relatively independent epidemiological region in China. These results improved our current understanding of the wheat stripe rust epidemic in northwestern and southwestern regions of China.

Population genetic characterization of Theileria annulata based on the cytochrome b gene, with genetic insights into buparvaquone susceptibility in Haryana (India)

The present investigation was aimed at population genetic characterization of Theileria annulata on the basis of the cytochrome b (cyt b) gene along with the evaluation of status of buparvaquone resistance in Haryana (India). The sequences originating from China, Egypt, India, Iran, Iraq, Tunisia, Turkey and Sudan were included in the analysis. The maximum likelihood tree based on the Tamura-Nei (TN93+G) model placed all the sequences of T. annulata into a single clade. The median-joining haplotype network exemplified geographical clustering between T. annulata haplotypes originating from each country. Only five haplotypes (7.81 %) were shared between any two countries, while the remaining 59 haplotypes (92.19 %) were singleton and unique to one country. The values of pairwise genetic distance (FST) between all the populations indicated huge genetic differentiation (> 0.25) between different T. annulata populations, barring the FST value between Iraq and Turkey (0.14454) which suggested a moderate differentiation. Contrary to the FST index, the values of gene flow (Nm) between T. annulata populations were very low. The neutrality indices and mismatch distributions indicated a population expansion in the Indian T. annulata population. Furthermore, the secondary structure and homology modeling of the partial cyt b protein is also reported. The molecular analysis of newly generated sequences for buparvaquone resistance revealed that all the isolates were susceptible to buparvaquone treatment. However, two novel mutations at positions V203I and V219I in between the Q01 and Q02 drug-binding regions of the cyt b gene were observed for the first time.

Comparative Chemical Study For Species of The Eryngium genus

Five species of Eryngium L. (Apiaceae) native to Iraq-Eryngium glomeratumLam, Eryngium creticum Lam, Eryngium thyrosoideum Boiss, Eryngium billardieri Lam., and L. Eryngium campestre—are the focus of this comparative chemical taxonomy. Chemical analysis revealed that the five species within the genus could be distinguished by their unique chemical signatures thanks to applying the GC Mass Spectrometer (GC-MS) technique to their secondary metabolic components. Species shared specific molecules but had distinct chemical make-ups in others. The chemical properties of the species in the genus were used to calculate Euclidean genetic distance values; the highest value was found to be 5.1962 between E.creticum and E.billardieri, and the pair with the smallest value of Euclidean distance (3.70) was E. campestre and E. billardieri. The clustering analysis was displayed in the phylogenetic tree. The species can be classified into three broad categories along a single Euclidean axis, as indicated by chemical evidence that corroborated the result of Principal Component Analysis (4.9). (PCA). The studies also demonstrated the ability to differentiate and identify evolutionary links across species by showing the independence of species in specific isolated chemicals. Keywords: Eryngium; genus; Chemical taxonomic; Lam Eryngium, (GC-MS) technique.

Genetska analiza gradskih golubova (Columba livia) kroz markere povezane s bojom perja u općini Montería, Córdoba, Kolumbija

The species known as the domestic pigeon, scientifically Columba livia, has managed to establish itself successfully in urban environments of numerous cities around the world. This expansion has become so significant that it has triggered concerns related to its tendency to nest in human-built structures. This nesting behaviour has contributed to the deterioration of these buildings. The distinctive presence of these birds in neighbourhoods and plazas has generated a growing interest in better understanding the genetic patterns that encode their varied coloration and plumage designs. The aim of this study was to investigate the genetic variability of the population of domestic pigeons (Columba livia) in Montería, Colombia, using phenotypic markers of plumage. Random sampling was conducted between March and April 2023 on 21 flocks of pigeons within the municipality of Montería. Through urban excursions, direct observation, and photographic records, 1570 individuals were phenotypically classified. Autosomal markers encoding coloration and plumage design were studied: Checker (C), Grizzle (G), Spread (S), and Ash-Red (B). The genetic profiles of subpopulations of domestic pigeons were established using the following genetic population indices: expected heterozygosity (He), total genetic diversity (HT), diversity within populations (HS), diversity between populations (DST), coefficient of genetic diversity (GST), gene flow (Nm), and genetic distance between populations. It was found that the most common allele in the studied populations is Checker, allelic frequencies ranged from 0.315 for the Checker gene to 0.005 for the Spread marker. Total genetic diversity was moderate, and genetic differentiation between populations was low, accompanied by a high gene flow. An excess of heterozygotes was also observed, and low genetic distance values were found between populations. The results indicate limited genetic differentiation among populations, leading to the conclusion that pigeon populations in Montería are highly related.

Characterization of the genetic diversity, structure, and admixture of 7 Chilean chicken breeds

The Mapuche fowl is an autochthonous breed raised in Chile and represents an important zoogenetic resource for the local economy. This study aimed at investigating the genetic diversity, relationship and population structure of 96 local Chilean chickens derived from 3 ecotype of Mapuche fowl (Kollonka, Ketro, and Kollonka de aretes), 2 ecotype Chilean (Trintre, Cogote pelado) and 2 breeds (Light Brahma and Barred Plymouth Rock) using 12 microsatellite markers. In total, 113 alleles were detected in all populations, with a mean of 7.6 alleles per population. In all population chicken breeds, the observed and expected heterozygosity ranged from 0.91 to 0.98 and from 0.69 to 0.79. Furthermore, all populations showed significant deviations from Hardy-Weinberg expectations. Across each population, the global heterozygosity deficit (FIT) was -0.174, population differentiation index (FST) was 0.073, and the global inbreeding of individuals within breed (FIS) was -0.267. The phylogenetic relationships of chickens were examined using neighbor-joining trees constructed at the level of population. The highest Nei's standard genetic distance value of 0.559 was observed between Barred Plymouth Rock and Light Brahma, whereas the minimum value (0.099) was found between Kollonka and Trintre. The neighbor-joining tree constructed at population level revealed 2 main clusters, with Light Brahma, Barred Plymouth Rock, Ketro and Kollonka de aretes in 1 cluster, and Kollonka, Trintre and Cogote pelado breeds in the second cluster. Based on the results of the STRUCTURE analysis, the most likely number of clustering of the population evaluated was at K=3, with Light Brahma and Barred Plymouth Rock breeds forming their own distinct clusters, while Kollonka, Ketro, Kollonka de aretes, Trintre and Cogote pelado breeds clustered together. This study represents the first report of genetic diversity in these populations in Chile. These results can be used as baseline genetic information for genetic conservation program, for instance, to control inbreeding and to implement further genetic studies in local Chilean chickens.

Phylogeographic inference for Bichromomyia flaviscutellata sensu stricto (Diptera: Psychodidae: Phebotominae) from the Brazilian Amazon rainforest, based on the 3' region of the COI gene.

Bichromomyia flaviscutellata (Mangabeira, 1942) sensu stricto (Diptera: Psychodidae) has been recognized as the main vector of Leishmania amazonensis in the Brazilian Amazon. For this reason, it is of paramount importance to understand the distribution of genetic diversity of populations of this vector, particularly the genetic structure and gene flow, for its management and control efforts. This study investigated the phylogeographic structure of five B. flaviscutellata s.s. populations from the central Brazilian Amazon region by analyzing 1,141 bp fragment of the 3' region of the COI gene. A total of 85 specimens of B. flaviscutellata s.s. were sequenced from Manaus (14), Rio Preto da Eva (10), Pitinga (14), Novo Airão (21), and Autazes (26); all in the state of Amazonas. The dataset yielded 59 haplotypes, most of them connected to each other in the main network. There were high levels of intrapopulation genetic variability (h = 0.945 ± 0.035 - 0.978 ± 0.054). The genetic distance values among populations varied from moderate (0.0873) to very high (0.3535), and all comparisons were significant, as well as the hierarchical analysis (ΦST = 0.2145). In contrast, these comparisons revealed a high number of shared sites (Ss = 6-34) and no difference in fixed sites (Sf = 0) among populations indicating absence of historical isolation. The Mantel test indicated that 67.92% (r = 0.6792; P = 0.06) of the genetic structure observed in B. flaviscutellata s.s. cannot be explained by the isolation-by-distance (IBD) model. This genetic structure, weakly explained by the IBD, may be due mainly by the forest habitat fragmentation and the low dispersal (flight) capacity of sand flies. Both factors could lead to population fragmentation and isolation, which promote genetic differentiation. Taken together, these findings suggest that the genetic structure observed in the studied populations of B. flaviscutellata s.s. is likely generated by microevolutionary processes acting at the population level at the present time and, therefore, evolutionary lineages were not recognized among the populations analyzed.

Molecular and morphometric study of Brazilian populations of Psychodopygus davisi.

In this study, we analysed the molecular and morphometric differences of several populations of the putative sand fly vector Psychodopygus davisi (Root, 1934) (Diptera, Psychodidae, Phlebotominae) in Brazil. We amplified the 658 base pair fragments of the DNA barcoding region-cytochrome c oxidase subunit 1 (COI) gene-for 57 specimens of P. davisi and three specimens of Psychodopygus claustrei (Abonnenc, Léger & Fauran, 1979). We merged our data with public sequences of the same species available from GenBank. Then, the combined dataset-87 sequences and 20 localities-was analysed using population structure analysis and different species delimitation approaches. Geometric morphometry of wings was performed for 155 specimens of P. davisi populations from the North, Midwest and Southeast Brazilian regions, analysing the differences in centroid sizes and canonical variates. Molecular analysis indicated high intraspecific genetic distance values for P. davisi (maximum p distance = 5.52%). All algorithms identified P. davisi and P. claustrei as distinct molecular taxonomic units, despite the low interspecific distance (p distance to the nearest neighbour = 4.79%). P. davisi sequences were split into four genetic clusters by population structure analysis and at least five genetic lineages using intermediate scenarios of the species delimitation algorithms. The species validation analysis of BPP strongly supported the five-species model in our dataset. We found high genetic diversity in this taxon, which is in agreement with its wide geographic distribution in Brazil. Furthermore, the wing analysis showed that specimens from the Southeast Region of Brazil are different from those in the North and the Midwest. The evolutionary patterns of P. davisi populations in Brazil suggest the presence of candidate species, which need to be validated in future studies using a more comprehensive approach with both genomic data and morphological characters.

Unveiling the molecular identity of the diminutive cyprinid, Horadandia brittani (Teleostei: Cyprinidae), a species endemic to Southern India.

Horadandia brittani is a small cyprinid fish species initially discovered in the coastal floodplains of southern India. For almost 50 years, the genus Horadandia was monotypic with a single species confined to Sri Lanka. In 1992, a new species H. brittani was described from south-western India. Despite being described as a separate species, H. brittani was later considered a synonym of H. atukorali, but in 2013, researchers recognized it as a distinct species based on morphological differences. Despite this clarification, there was still a need to validate the identity of H. brittani and determine its evolutionary relationship with its closely related species using DNA sequences. To address the uncertainties surrounding the identity of H. brittani, the present study utilized molecular techniques to generate DNA sequences. Sample collection involved obtaining specimens of H. brittani from their natural habitats. Subsequently, DNA was extracted from the collected samples, and the mitochondrial cytochrome C oxidase (COI) gene was amplified using appropriate methods. The analysis of DNA sequences obtained from the COI gene revealed significant genetic distinctions between H. brittani and H. atukorali. The genetic distance values between these two species ranged from 3.21 to 3.63%, clearly indicating that these two species are genetically separate entities. The study successfully established the phylogenetic relationships between H. brittani and H. atukorali based on the COI gene sequences, further confirming the validity of H. brittani as a distinct and separate species. The findings of this study conclusively demonstrate that H. brittani is a valid and separate species, distinct from H. atukorali. The genetic analysis based on mitochondrial COI gene sequences provided strong evidence for the differentiation between these two species. The molecular data generated in this research can be used to identify H. brittani quickly and accurately in the future.