Minimum Genetic Distance Research Articles

Taxonomic resolution of the hillstream suck-loach Beaufortia pingi species group (Cypriniformes, Gastromyzontidae) and two new species from Southwest China– Beaufortia granulopinna and Beaufortia viridis

Two new species, Beaufortia granulopinna and Beaufortia viridis, are described from the upper Pearl River system in southwest China. Both species share the characteristics of the Beaufortia pingi species group, including prominent vertical stripes on the lateral body and pinnate-type lower lips, distinguishing them from other Beaufortia species. Beaufortia granulopinna is differentiated from other species in the group by possessing a unique set of characteristics: the presence of well-developed prominent tubercles on the first 6–9 pectoral fin rays in adults; and a significant proportion (54.76%) of individuals experiencing blurriness or absence of vertical stripes in the mid-section of the lateral body upon reaching adulthood. The minimum interspecific genetic distance within the genus based on mitochondrial cytb gene sequences is 10.80%. Beaufortia viridis is distinguished from other species in the group by consistently exhibiting vertical stripes of uniform length, width, and spacing across all stages of growth; the absence of tubercles on the branched rays of pectoral fins; and a body coloration of dark cyan to green. The minimum interspecific genetic distance within the genus based on mitochondrial cytb gene sequences is 4.60%. Molecular phylogenetic results confirm that the Beaufortia pingi species group forms a monophyletic clade, which is congruent with morphological classification findings. This study also addresses and resolves the taxonomic ambiguity surrounding Beaufortia pingi and Beaufortia zebroida, providing a redescription of these taxa.

Decoding the molecular phylogenetics of ornamental catfishes (siluriformes) of North East India using DNA barcoding approach.

Catfishes (order Siluriformes) are among the most diverse and widely distributed fish groups in the world. They are not only used for human consumption but are also a major part of the ornamental fish trade. Being a Biodiversity Hotspot, the North Eastern Region of India is home to a diverse population of ornamental fishes. Catfishes contain a humongous number of species; in this study, the authors have tried to elucidate the phylogenetic relationship of some important ornamental catfishes found in North East India using DNA barcodes. In this study, we have tried to explore the phylogenetic history of 13 species (41 specimens) of ornamental catfishes spanning 12 genera and 9 families of Siluriformes using DNA barcoding. Pairwise genetic distances using Kimura 2-Parameter (K2P) were calculated at intra-specific and inter-specific levels. A Neighbor-Joining tree was constructed to understand the phylogenetic relationship among the nine different catfish families. All the specimens under this study clustered with their respective species under the same family and formed three sub-clades. However, Olyra longicaudata, belonging to the Bagridae family, did not cluster with other species from the same family. In this study, the authors have suggested a revision of the classification of O. longicaudata back to its original family, Olyridae. In this study, the maximum intraspecific genetic distance of 0.03 and the minimum interspecific genetic distance of 0.14 were observed among the species. Therefore, it is evident that there is a barcoding gap among the species, which helped in the correct identification of the species. Thus, DNA barcoding helped complement the phenetic approach and also revealed a different phylogenetic relationship among the catfishes belonging to the Bagridae family.

Genetic variations among the isolates of Bipolaris Maydis based on phenotypic and molecular markers

Abstract Maydis leaf blight, caused by Bipolaris maydis, is an important disease of maize crop in Khyber Pakhtunkhwa (KP) Pakistan. Fifteen isolates of the pathogen, collected across KP, were studied for variability based on phenotypic and molecular markers. Significant variability among the isolates was observed when assessed using phenotypic traits such as radial growth, spore concentration, fungicide sensitivity and virulence. The isolates were classified into six culture groups based on colour, texture and margins of the colony. Conidial morphology was also variable. These were either straight or slightly curved and light to dark brown in colour. Fungicide test showed significant variation in the degree of sensitivity against Carbendazim. Isolate Bm8 exhibited maximum radial growth on carbendazim spiked plates. Conversely, isolate Bm15 showed the lowest radial growth. Variations in virulence pattern of the isolates were evident when a susceptible maize variety Azam was inoculated with spores of B. maydis. Genetic variability amongst the isolates was also estimated by RAPD as well as sequencing of ITS region. The RAPD dendrogram grouped all the isolates into two major clusters. Average genetic distance ranged from 0.6% to 100%, indicating a diverse genetic gap among the isolates. Maximum genetic distance was found between isolates Bm9 and Bm10 as well as Bm2 and Bm8. Conversely, isolates Bm13 and Bm15 were at minimum genetic distance. Phylogenetic dendrogram based on sequencing of ITS region grouped all the isolates into a single major cluster. The clusters in both the dendrogram neither correlate to the geographical distribution nor to the morphological characteristics.

Influence of biotic and abiotic factors on the virulence of Puccinia triticina population in southern Russia

AbstractWheat leaf rust, caused by Puccinia triticina, is reported annually in southern Russia, the main wheat production region in Russia. The effect of biotic (types of cultivar resistance) and abiotic (northern, central and southern agro‐ecological zones) factors on virulence variability of the pathogen was analysed with 43 Lr differentials. Virulence frequencies to Lr genes 1, 2c, 3, 3bg, 11, 14a, 14b, 16, 17, 18, 23, 25, 26, 33, 34, 40 and Kanr exceeded 50% in all populations. A total of 81 virulence phenotypes (based on the standard set of 20 differentials) were identified among 108 isolates. The most common phenotypes were PHSTQ, THTTR, PHTTR and TKTTR. The minimum genetic distance (the highest similarity) was established between the P. triticina populations from susceptible cv. Krasnodarskaya 99 and cv. Brigada with race‐specific resistance. P. triticina populations from the susceptible cultivar in the three agro‐ecological zones were less variable and more similar than the cultivar‐specific and natural pathogen populations. Resistance types of host cultivars seem to have a greater effect on the pathogen population than abiotic factors. Nevertheless, abiotic factors need to be considered when making decisions about deployment of wheat varieties. Our results support the paradigm of a shift in the population of an obligate parasite towards increased virulence in response to the selection pressure of cultivars with race‐specific resistance.

Multivariate analysis for yield and yield-related traits of oat (Avena sativa L.) genotypes in Ethiopia

The study aimed to generate information on agro-morphological variability among the 120 oat genotypes in the central highlands of Ethiopia. The result showed that the hierarchical clustering grouped the genotypes into four clusters. The highest number of genotypes grouped into the first cluster (38) followed by the second cluster (35) and the fourth cluster (33) while the lowest genotypes (14) were recorded in the third cluster. High forage yield-producing genotypes were grouped into the second cluster while high grain-producing genotypes were grouped into the third cluster. The intra-cluster genetic distance values ranged from 4.3 (C3) to 2.3 (C1). The minimum inter-cluster genetic distance was recorded at 11.7 (between C1 and C2), while the maximum inter-cluster distance was 63.2 (between C3 and C4). Principal component analysis showed that the first four principal components with eigenvalues greater than one contributed 78.3% of the variability among genotypes. The highest contributing traits in the first component were forage yield production rate, biological yield production rate, panicle length at grain harvest, forage dry matter yield, and number of spikelets per panicle. The traits with the greatest weight on the second component were harvest index, grain yield, number of leaves at forage harvest, and plant height at grain harvest. Proper selection of best yield performing genotypes coupled with high yield contributing traits is very important to yield improvement and future oat breeding program. Therefore, selection based on the traits that had a high contribution to the first two principal components would be effective for yield improvement in oat genotypes.

Molecular Evolution of Human Parainfluenza Virus Type 2 Based on Hemagglutinin-Neuraminidase Gene.

To understand the molecular evolution of human parainfluenza virus type 2 (HPIV2), 21 Hemagglutinin-Neuraminidase (HN) gene sequences covering seven Chinese provinces in 2011 and 2017 to 2021 were combined with 90 published HN sequences worldwide for phylogenetic analysis. The result showed that global HPIV2 could be classified into two distinct clusters (I and II), five lineages (IA to IIE), and four sublineages (IB1 and 2, and IIE1 and 2). The minimum genetic distances between different clusters and lineages were 0.049 and 0.014, respectively. In the last decade, one lineage (IID) and three sublineages (IB1, IB2, and IIE1) have been cocirculating in China, with the sublineages IB2 and IIE1 dominating, while sublineages IB1 and IIE1 are dominant globally. In addition, the spread of HPIV2 had relative spatial clustering, and sublineage IB2 has only been detected in China thus far. The overall evolution rate of HPIV2 was relatively low, on the order of 10-4 substitutions/site/year, except for sublineage IB2 at 10-3 substitutions/site/year. Furthermore, human-animal transmission was observed, suggesting that the HPIV2 might have jumped out of animal reservoirs in approximately 1922, the predicted time of a common ancestor. The entire HN protein was under purifying/negative selection, and the specific amino acid changes and two novel N-glycosylation sites (N316 and N517) in sublineages IB1, IB2, and IIE1 were mostly located in the globular head region of the HN protein. In this study, preliminary evolutionary characteristics of HPIV2 based on the HN gene were obtained, increasing the recognition of the evolution and adaptation of HPIV2. IMPORTANCE The phylogenetic analysis showed that global HPIV2 could be classified into two distinct clusters (I and II) and five lineages (IA to IIE) with at least 0.049 and 0.014 genetic distances between clusters and lineages, respectively. Furthermore, lineages IB and IIE could be further divided into two sublineages (IB1-2 and IIE1-2). All China sequences belong to one lineage and three sublineages (IB1, IB2, IID, and IIE1), among which sublineages IB2 and IIE1 are predominant and cocirculating in China, while sublineages IB1 and IIE1 are dominant globally. The overall evolution rate of HPIV2 is on the order of 10-4 substitutions/site/year, with the highest rate of 2.18 × 10-3 for sublineage IB2. The entire HN protein is under purifying/negative selection, and the specific amino acid substitutions and two novel N-glycosylation sites (N316 and N517) in sublineages IB1, IB2, and IIE1 are mostly located in the globular head region of the HN protein.

Testing the effectiveness of rbcLa DNA-barcoding for species discrimination in tropical montane cloud forest vascular plants (Oaxaca, Mexico) using BLAST, genetic distance, and tree-based methods.

DNA-barcoding is a species identification tool that uses a short section of the genome that provides a genetic signature of the species. The main advantage of this novel technique is that it requires a small sample of tissue from the tested organism. In most animal groups, this technique is very effective. However, in plants, the recommended standard markers, such as rbcLa, may not always work, and their efficacy remains to be tested in many plant groups, particularly from the Neotropical region. We examined the discriminating power of rbcLa in 55 tropical cloud forest vascular plant species from 38 families (Oaxaca, Mexico). We followed the CBOL criteria using BLASTn, genetic distance, and monophyly tree-based analyses (neighbor-joining, NJ, maximum likelihood, ML, and Bayesian inference, BI). rbcLa universal primers amplified 69.0% of the samples and yielded 91.3% bi-directional sequences. Sixty-three new rbcLa sequences were established. BLAST discriminates 80.8% of the genus but only 15.4% of the species. There was nil minimum interspecific genetic distances in Quercus, Oreopanax, and Daphnopsis. Contrastingly, Ericaceae (5.6%), Euphorbiaceae (4.6%), and Asteraceae (3.3%) species displayed the highest within-family genetic distances. According to the most recent angiosperm classification, NJ and ML trees successfully resolved (100%) monophyletic species. ML trees showed the highest mean branch support value (87.3%). Only NJ and ML trees could successfully discriminate Quercus species belonging to different subsections: Quercus martinezii (white oaks) from Q. callophylla and Q. laurina (red oaks). The ML topology could distinguish species in the Solanaceae clade with similar BLAST matches. Also, the BI topology showed a polytomy in this clade, and the NJ tree displayed low-support values. We do not recommend genetic-distance approaches for species discrimination. Severe shortages of rbcLa sequences in public databases of neotropical species hindered effective BLAST comparisons. Instead, ML tree-based analysis displays the highest species discrimination among the tree-based analyses. With the ML topology in selected genera, rbcLa helped distinguish infra-generic taxonomic categories, such as subsections, grouping affine species within the same genus, and discriminating species. Since the ML phylogenetic tree could discriminate 48 species out of our 55 studied species, we recommend this approach to resolve tropical montane cloud forest species using rbcLa, as an initial step and improve DNA amplification methods.

Exploring the Genetic Diversity and Population Structure of Wheat Landrace Population Conserved at ICARDA Genebank.

Landraces are considered a valuable source of potential genetic diversity that could be used in the selection process in any plant breeding program. Here, we assembled a population of 600 bread wheat landraces collected from eight different countries, conserved at the ICARDA's genebank, and evaluated the genetic diversity and the population structure of the landraces using single nucleotide polymorphism (SNP) markers. A total of 11,830 high-quality SNPs distributed across the genomes A (40.5%), B (45.9%), and D (13.6%) were used for the final analysis. The population structure analysis was evaluated using the model-based method (STRUCTURE) and distance-based methods [discriminant analysis of principal components (DAPC) and principal component analysis (PCA)]. The STRUCTURE method grouped the landraces into two major clusters, with the landraces from Syria and Turkey forming two clusters with high proportions of admixture, whereas the DAPC and PCA analysis grouped the population into three subpopulations mostly according to the geographical information of the landraces, i.e., Syria, Iran, and Turkey with admixture. The analysis of molecular variance revealed that the majority of the variation was due to genetic differences within the populations as compared with between subpopulations, and it was the same for both the cluster-based and distance-based methods. Genetic distance analysis was also studied to estimate the differences between the landraces from different countries, and it was observed that the maximum genetic distance (0.389) was between the landraces from Spain and Palestine, whereas the minimum genetic distance (0.013) was observed between the landraces from Syria and Turkey. It was concluded from the study that the model-based methods (DAPC and PCA) could dissect the population structure more precisely when compared with the STRUCTURE method. The population structure and genetic diversity analysis of the bread wheat landraces presented here highlight the complex genetic architecture of the landraces native to the Fertile Crescent region. The results of this study provide useful information for the genetic improvement of hexaploid wheat and facilitate the use of landraces in wheat breeding programs.

Exploring Large-Scale Patterns of Genetic Variation in the COI Gene among Insecta: Implications for DNA Barcoding and Threshold-Based Species Delimitation Studies.

Simple SummaryInsecta is the most diverse group in the kingdom Animalia, and it accounts for approximately two-thirds of all animals. The most commonly used gene for species delimitation in animals is cytochrome c oxidase subunit 1 (COI). We calculated the genetic distance of 64,414 insect species, downloaded from BOLD, and found that approximately one-quarter of the species of Insecta showed high intraspecific genetic variation (>3%). Owing to the high intraspecific genetic variation in insects, false positives may easily occur in threshold-based species delimitation based on the COI gene. Compared to the fixed thresholds, the thresholds that were calculated from the “threshOpt” and “localMinima” algorithms that are embedded in the Spider package are recommended in threshold-based species delimitation studies.The genetic variation in the COI gene has had a great effect on the final results of species delimitation studies. However, little research has comprehensively investigated the genetic divergence in COI among Insecta. The fast-growing COI data in BOLD provide an opportunity for the comprehensive appraisal of the genetic variation in COI among Insecta. We calculated the K2P distance of 64,414 insect species downloaded from BOLD. The match ratios of the clustering analysis, based on different thresholds, were also compared among 4288 genera (35,068 species). The results indicate that approximately one-quarter of the species of Insecta showed high intraspecific genetic variation (>3%), and a conservative estimate of this proportion ranges from 12.05% to 22.58%. The application of empirical thresholds (e.g., 2% and 3%) in the clustering analysis may result in the overestimation of the species diversity. If the minimum interspecific genetic distance of the congeneric species is greater than or equal to 2%, it is possible to avoid overestimating the species diversity on the basis of the empirical thresholds. In comparison to the fixed thresholds, the “threshOpt” and “localMinima” algorithms are recommended for the provision of a reference threshold for threshold-based species delimitation studies.

The real Devario browni from the Irrawaddy River basin, and the new Devario ahlanderi from the Salween River basin in Myanmar (Teleostei: Cyprinidae: Danioninae).

Specimens of Devario from a tributary to the Salween River in Myanmar initially identified as Devario browni but with a different colour pattern, were subjected to a comparative morphological analysis with syntypes and other specimens of D. browni from near its putative type locality. The Salween sample was recognised as representing a distinct species, here named Devario ahlanderi. No significant morphometric differences were found between D. ahlanderi and D. browni. The type series of Devario ahlanderi differed from D. browni and most other species of Devario in the presence of 14 vs 12 circumpeduncular scale rows. Devario ahlanderi, D. browni, and D. fangae shared subadult colour pattern. Adult D. ahlanderi differed from adult D. browni in the trunk colour pattern, consisting of rows of dark blotches or short vertical bars. In D. browni, the flank colour pattern consisted of horizontal dark stripes, the middle of which (the P stripe) frequently diverged anteriorly, enclosing a small light blotch. Specimens previously reported as D. browni from the upper Salween River basin in Yunnan differed slightly in colour pattern, and may represent a distinct species. Devario ahlanderi shared spotted colour pattern with that of one ontogenetic state in D. kysonensis, except that a row of spots marking the P-1 stripe in D. kysonensis was absent in D. ahlanderi. The minimum genetic distance between D. ahlanderi and congeneric species varied from 2.1 to 5% in the mt-coI gene.

DNA polymorphism and relationships among the three different riverine populations of spotted snakehead (Channa punctata)

The current study was aimed to investigate the DNA polymorphism of C. punctata from three different rivers of northern region of India. For this, C. punctata of river Ganga and its tributaries (river Gomti and river Ken) was carried out using RAPD-PCR (Random amplified polymorphic DNA-polymerase chain reaction). A total of 54 loci were amplified by five selected primers out of 20 having GC content of 60% to 70%. The fish population of river Ganga showed highest genetic polymorphism with 33 (61.11%) polymorphic loci out of 54 loci whereas a total of 55.56% and 46.30% DNA polymorphism were recorded in the fish populations of Ken and Gomti respectively. Maximum genetic identity and minimum genetic distance was recorded between the fish populations of Ganga and Ken showing that these two populations are more similar to each other than to Gomti population. Dendogram based on genetic distance using UPGMA also confirmed that Ganga and Ken population are closer to each other.

Determination of Genetic Diversity Based on RAPD molecular Marker and ParARF3 Gene Expressions in some Apricot Genotypes in Iraq

Employing DNA markers allowed determining genetic diversity and relationships amongst five apricot genotypes. In this study, two relative gene expressions pertaining to ParARF3 gene, which could be distinguished from the genotypes that were exposed to various concentrations of marine alga treatments. As per our results, screening of seven primers with the DNA of 5 apricot genotypes was done, and six primers were generated while the primer OPN–16 gave negative results. The total quantity of fragments generated by 6 primers was 80 at an average of 13.33 fragments ̸primer. The highest unique percentage band depicted in U-17 touched 23%, and the total number of polymorphic bands touched 17 fragments with the average reaching 2.83 fragments ̸primer. The number of monomorphic lied in the range of 5 to 10, with a total of 47 monomorphic. Primer M 32 yielded the highest number of monomorphic bands reaching 10. Between Zaghenia and Zinni, a maximum genetic distance value of 0.8 was reached with less similarity value of 20%. A minimum genetic distance value of 0.44721 was noted between Kaisy and Baia while the high similarity value touched 55.3%. According to the cluster tree analysis, the genotypes were generally split into two key groups: A and B. The Zinni group, which included one apricot genotype, showed genetic similarity of 20% with the other genotypes present in B group. The B group was split into two sub-clusters B1 and B2 and the genetic similarity reached 44%. The ParARF3 relative gene expression pertaining to Zinni genotypes was second as well as convergent with that of gene expression for Zaghenia genotype results. Baia and Kaisy genotypes lied in between the lowest and highest ParARF3 value gene expression exposed to Marine Alga. These outcomes showed that RAPD markers offer an effectual alternative for the plant species genetic characterisation.

Estimation of Genetic Diversity among Canola Accessions using Simple Sequence Repeat Markers

Genetic studies through molecular markers proved important to find out the genetic diversity of canola. In this study, 50 lines of canola were used to find the polymorphism using 15 SSR primers and investigated the genetic diversity, PIC values, frequency-based genetic distance, and allelic frequencies. Mean gene diversity, frequency-based genetic distance, and PIC values were 0.8777, 0.233 and 0.8666, respectively for the canola lines. A good range of genetic diversity was found among studied canola lines with value 85.91% polymorphism. Maximum and minimum genetic distances among 50 lines were 1 and 0.26, respectively. Accessions ACC-26068, ACC-24241, ACC-24244, ACC-24233, ACC-24423 and ACC-24224 have maximum genetic distance. Accessions ACC-24879 and ACC-24169 had minimum genetic distance i.e., 0.26. Dendrogram based on genetic distances showed four main clusters that were further dividing into several sub-clusters. The primers utilized in the present study, were valuable to identify different accessions of canola to find the variability present. This variability will be helpful to initiate the breeding program with their molecular genetic basis.

Agro-morphological and genetic diversity studies in Rice (Oryza sativa L.) germplasm using microsatellite markers.

Knowledge of the genetic diversity and population structure of germplasm collections is an important foundation for crop improvement. Rice production across a broad range of rice-growing environments results in a diverse array of local rice varieties. Many rice varieties have been lost as a result of biodiversity loss and are now grown in Pakistan. To protect the biodiversity of rice varieties, an experiment was carried out to check the genetic and morphological variations between 8 exotic and 7 local rice genotypes, using 5 different SSR markers, i.e., RM3, RM259, RM341, RM520, and RM11943. The analysis of morphological and quality traits of rice observed significant variation across genotypes. The results revealed that genotype Irri-Pak attained the highest plant height and primary branch plant-1, while genotype Mushkan produced a higher number of productive tillers and obtained a higher fertility factor (%). Similarly, the highest value for panicle length was observed for genotype Faker-e-Malakand, 1000-grains weight in genotype Calmochi, and maximum days to maturity was noticed in genotype Swati-2014. Moreover, the genotype Brio attained the highest value of stem diameter, while maximum seed length was noted in the genotype Sug Dasi. The highest number of primary branches plant-1 in genotype Ibge-I and secondary branches plant-1 in genotype Calmochi were noticed. A higher concentration of sodium and potassium was observed for the genotype Marte, while the genotype Muskan attained the maximum content of copper. Moreover, the highest concentration of iron in genotype Originario, zinc in genotype JP-5, and cadmium content were noticed in genotype Ibge. Similarly, the dendrogram analysis for quantitative parameters showed three clusters at 74.13% similarities. Whereas all the genotypes of European origin formed a separate cluster. A set of 5 simple sequence repeat primers, covering four chromosomes, amplified a total of 14 alleles and showed 100% polymorphism with an average PIC value ranging from 0.39 to 0.91. The UPGMA cluster analysis separated the 15 rice genotypes into 3 main groups based on 32.5% similarities and the highest genetic distance (45.1%) was observed between two genotypes (Fakher-e-malakand and Musa), having different geographical origins. There was no genetic distance between the genotypes Marte and Brio, irrespective of having the same origin. The maximum genetic distances were noted for genotype, Fakhre-e-Malakand and Musa having a different origin, while the minimum genetic distance was shown by genotypes, Marte and Onice, from the same origin.

Patterns of reproductive isolation in a haplodiploid mite, Amphitetranychus viennensis: prezygotic isolation, hybrid inviability and hybrid sterility

BackgroundEvolution of reproductive isolation is an important process, generating biodiversity and driving speciation. To better understand this process, it is necessary to investigate factors underlying reproductive isolation through various approaches but also in various taxa. Previous studies, mainly focusing on diploid animals, supported the prevalent view that reproductive barriers evolve gradually as a by-product of genetic changes accumulated by natural selection by showing a positive relationship between the degree of reproductive isolation and genetic distance. Haplodiploid animals are expected to generate additional insight into speciation, but few studies investigated the prevalent view in haplodiploid animals. In this study, we investigate whether the relationship also holds in a haplodiploid spider mite, Amphitetranychus viennensis (Zacher).ResultsWe sampled seven populations of the mite in the Palaearctic region, measured their genetic distance (mtDNA) and carried out cross experiments with all combinations. We analyzed how lack of fertilization rate (as measure of prezygotic isolation) as well as hybrid inviability and hybrid sterility (as measures of postzygotic isolation) varies with genetic distance. We found that the degree of reproductive isolation varies among cross combinations, and that all three measures of reproductive isolation have a positive relationship with genetic distance. Based on the mtDNA marker, lack of fertilization rate, hybrid female inviability and hybrid female sterility were estimated to be nearly complete (99.0–99.9% barrier) at genetic distances of 0.475–0.657, 0.150–0.209 and 0.145–0.210, respectively. Besides, we found asymmetries in reproductive isolation.ConclusionsThe prevalent view on the evolution of reproductive barriers is supported in the haplodiploid spider mite we studied here. According to the estimated minimum genetic distance for total reproductive isolation in parent population crosses in this study and previous work, a genetic distance of 0.15–0.21 in mtDNA (COI) appears required for speciation in spider mites. Variations and asymmetries in the degree of reproductive isolation highlight the importance of reinforcement of prezygotic reproductive isolation through incompatibility and the importance of cytonuclear interactions for reproductive isolation in haplodiploid spider mites.

Genetic Characterization of Swamp Eel of Bangladesh Through Dna Barcoding and Rapd Techniques

The freshwater air-breathing swamp eel Monopterus spp. are native to the freshwater of Bangladesh and throughout the Indian subcontinent. To identify the different swamp eel species and to check the genetic diversity among them, a total of twelve swamp eel specimens were collected from four districts (Tangail, Bogura, Bagerhat and Sylhet) representing the four division of Bangladesh. The extracted DNA from twelve fish samples was amplified by the PCR technique for DNA barcoding and RAPD analysis. Among 12 specimens, 8 specimens showed a 95-100% similarity with M. cuchia species published in the NCBI GenBank database and BOLD system. The studied mct3 (collected from Tangail region), mcs1, mcs2 and mcs3 (collected from Sylhet region) specimens showed about 83% homology with Ophisternon sp. MFIV306-10 as per BLAST search; whereas BOLD private database showed 99% similarity with Ophisternon bengalense (Bengal eel). From the phylogenetic tree analysis, 8 samples were clustered with M. cuchia and 4 samples showed similarity with Ophisternon sp. MFIV306-10 and Ophisternon bengalense _ANGBF45828-19. In RAPD-PCR based analysis, it was found that the maximum genetic distance (1.6094) was observed between mcba2 and mcs3, while between mct1 and mct2, the minimum genetic distance was 0.000. A total of 192 bands, of which 35 were polymorphic with 17.88% polymorphisms among swamp eel species and the size of the amplified DNA fragments ranged from 250 to 1800 bp. The information on DNA barcoding and RAPD analysis help measure the genetic diversity among swamp eel species, ensure the reliability of the published taxonomic information, and initiate proper management programs to conserve these vulnerable species to meet future export demand.
 Asiat. Soc. Bangladesh, Sci. 46(2): 117-131, December 2020

A new species of crayfish of the genus Cambarellus (Decapoda: Cambaridae) from central Mexico

Previous studies suggested that populations of the genus Cambarellus inhabiting La Laja river could correspond to an undescribed taxon. Morphometric analysis of the variation in 15 body traits and molecular analysis from 5 genetic markers were carried on individuals from such localities and other Cambarellus species. Principal component analyses and multivariate analyses of covariance resulted in the identification of significant differences between the newly proposed species and the rest of the analyzed Cambarellus species. Phylogenetic analyses placed populations from La Laja in a monophyletic clade with a COI minimum genetic distance of 8.4%. Based on these findings, it was concluded that this is a distinct species when compared with the rest of Cambarellus . We present the formal description of Cambarellus ( Cambarellus ) moi sp. nov. In comparison with the rest of species, the new species has a longer cephalon (0.30-0.37 times in total length), longer (0.14-0.10 times in total length) and wider rostrum (0.3-0.53 in rostrum length), and a longer antennal scale (0.60-1.0 in rostrum length). Characteristics such as size and shape of the apical processes of the first pleopod of the form I male can be used to distinguish the new species.

Identification of Cannabis Sativa L. Based on rbcL Sequence.

Objective To assess the feasibility of the rbcL sequence of chloroplast DNA as a genetic marker to identify Cannabis sativa L. Methods The rbcL sequences in 62 Cannabis sativa L. samples, 10 Humulus lupulus samples and 10 Humulus scandens DNA samples were detected, and 96 rbcL sequences of the Cannabaceae family were downloaded from Genbank. Sequence alignment was performed by MEGA X software, the intraspecific and interspecific Kimura-2-Parameter （K2P） genetic distances were calculated, and the system clustering tree was constructed. Results The rbcL sequence length acquired by sequencing of Cannabis sativa L. and Humulus scandens were 617 bp and 649 bp, respectively, and two haplotypes of Cannabis sativa L. were observed in the samples. The BLAST similarity search results showed that the highest similarity between the sequences acquired by sequencing and Cannabis sativa L. rbcL sequences available from Genbank was 100%. The genetic distance analysis showed that the maximum intraspecific genetic distance （0.004 9） of Cannabis sativa L. was less than the minimum interspecific genetic distance （0.012 9）. The results of median-joining network and system clustering tree analysis showed that Cannabis sativa L. and other members of the Cannabaceae family were located in different branches. Conclusion The rbcL sequence could be used as a DNA barcode for identifying Cannabis sativa L., and combined with comparative analysis of the rbcL sequence and system cluster analysis could be a reliable and effective detection method for Cannabis sativa L. identification in forensic investigation.

Microscopic and Molecular Description of the Microsporidian Parasite,Heterosporis sp., Infecting Lizardfish, Saurida undosquamis in the Persian Gulf

Background: The lizardfish is an economically important fish in the Persian Gulf with high rates of parasitic infections. Microsporidia species, as opportunistic parasites, cause several disorders, which in turn result in economic problems. Objectives: The main objective was to evaluate Heterosporis sp. infection in Persian Gulf lizardfish using the small subunit ribosomal RNA phylogenetics to describe and classification of the unknown microsporidia species as well as morphological characteristics. Methods: The abdominal cavities of fifty specimens of lizardfish, Saurida undosquamis, were examined using morphological and molecular techniques. Some irregular whitish cyst-like were fixed for histopathological and transmission electron observations. The small subunit ribosomal genomic DNA was studied and a 1,279 bp genomic sequence was amplified and investigated for molecular analysis. Results: Twenty-two (out of fifty) specimens were infected with irregular whitish microsporidian cysts. Light and electron microscopic findings revealed round cysts containing large numbers of monomorphic and ovoid spores with a posterior vacuole. Polar tube coiled between six and eight-times, in one row. The large xenoma (hypertrophied parasitizing host cells) was encapsulated by a host-derived thick connective tissue in pathological samples. The phylogenetic analysis showed that despite some morphological similarity of the Persian Gulf microsporidia sp. to Glugea spp., the most closely related species with minimum genetic distance to Heterosporis anguillarum isolated is Japanese eels (Anguillajaponica). Conclusions: This is the first phylogenetic report of microsporidian infections in mesenteric tissues of lizardfish S. undosquamis in Iran including morphological and molecular markers, to introduce novel species

Genetic differentiation among Himalayan and local Mahseer populations

This study of Genetic Differentiation among Himalayan & local Mahseer concerns with a conservation plan is a fundamental part of the hydro projects still in the pipeline. In-situ conservation and gene banking also serve as the best medium for the same. Despite conservation programs, re-examination and revision of these conservation areas to update the number and lists of endangered status are mandatory. Fish samples collected from 8 different waterbodies {Chambal River, Rana Pratap Sagar Dam, Bassi Dam, Kali Sindh River, Parwan River, Badi Lake, Daya Dam, and Madar Tank} representing two major drainage systems (the Bay of Bengal and the Arabian Sea) of India. For the cytochrome oxidase subunit I, a total of 32 sequences was generated, whereas, for the ATPase 6 gene, a total of 66 sequences were generated. Two mitochondrial regions COI and ATPase6 were amplified using the set (Forward & Reverse primer set) of published primers (COI-Fish F-1/Fish R-1. BOLD-IDS was used to test the efficiency of DNA barcoding as a species identification tool using a blind sampling test, the sample selected & sequenced were known only to the submitting individual. Mismatch distributions to evaluate the hypothesis of recent population growth with 99,999 permutations as implemented in ARLEQUIN 3.0.1 was used. This distribution is unimodal in populations that have passed through a recent demographic expansion and are multimodal in stable populations. A DNA sequence of Himalayan Mahseer (Tor tor) was downloaded from NCBI Gene Bank and the sequences generated in the present study were compared (Using MEGA7 Software) with the downloaded sequence. It’s derived that the stocks of Rajasthan Mahseer are quite distinct from the Himalayan stocks. The minimum genetic (116.06) distance was noticed for both Daya dam and Madar Tank and the highest (125.35) was for Bassi Dam. The evolutionary history was inferred using the Minimum Evolution method. The optimal tree with the sum of branch length 123.79668059. The significantly higher genetic distance between Rajasthan and Himalayan stocks could be due to geographic location and mainly isolated aquatic resources. Similar findings have also been reported by earlier workers.