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772 result(s) for "Haplotype networks"
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Dispersion routes of the main vectors of human malaria in the Americas: Genetic evidence from the mitochondrial COI gene
Background and objectives: In America, of the 44 species of Anopheles, nine are main vectors of malaria and, of these, genetic information exists for seven. Hence, this study sought to know the gene flow and diversity of the seven principal vectors of malaria at the Americas level. Methods: For the seven species and the sequences of the mitochondrial cytochrome c oxidase I (COI) gene obtained from the GenBank and Bold System, genetic analyzes of populations and genetic structure were performed and haplotype networks and phylogenetic trees were obtained. Results: For the seven species, 1440 sequences were analyzed and 519 haplotypes were detected. The Hd and π values were higher within a continental context than by countries. Neutrality tests indicated positive and negative values with most of these being significant (p < 0.05). Phylogenetic analyses for all the species recovered three clades with no geographic pattern among them. Interpretation & conclusion: Studies suggest that native species of Anopheles from the Americas have greater haplotype diversity and low genetic differentiation due to the lack of physical barriers to impede gene flow among these populations. Moreover, all the species are interconnected by roadways. This scenario complicates the epidemiological picture of malaria in the Americas.
From metabarcoding to metaphylogeography
Metabarcoding is by now a well-established method for biodiversity assessment in terrestrial, freshwater, and marine environments. Metabarcoding data sets are usually used for α- and β-diversity estimates, that is, interspecies (or inter-MOTU [molecular operational taxonomic unit]) patterns. However, the use of hypervariable metabarcoding markers may provide an enormous amount of intraspecies (intra-MOTU) information—mostly untapped so far. The use of cytochrome oxidase (COI) amplicons is gaining momentum in metabarcoding studies targeting eukaryote richness. COI has been for a long time the marker of choice in population genetics and phylogeographic studies. Therefore, COI metabarcoding data sets may be used to study intraspecies patterns and phylogeographic features for hundreds of species simultaneously, opening a new field that we suggest to name metaphylogeography. The main challenge for the implementation of this approach is the separation of erroneous sequences from true intra-MOTU variation. Here, we develop a cleaning protocol based on changes in entropy of the different codon positions of the COI sequence, together with co-occurrence patterns of sequences. Using a data set of community DNA from several benthic littoral communities in the Mediterranean and Atlantic seas, we first tested by simulation on a subset of sequences a two-step cleaning approach consisting of a denoising step followed by a minimal abundance filtering. The procedure was then applied to the whole data set. We obtained a total of 563 MOTUs that were usable for phylogeographic inference. We used semiquantitative rank data instead of read abundances to perform AMOVAs and haplotype networks. Genetic variability was mainly concentrated within samples, but with an important between seas component as well. There were intergroup differences in the amount of variability between and within communities in each sea. For two species, the results could be compared with traditional Sanger sequence data available for the same zones, giving similar patterns. Our study shows that metabarcoding data can be used to infer intra- and interpopulation genetic variability of many species at a time, providing a new method with great potential for basic biogeography, connectivity and dispersal studies, and for the more applied fields of conservation genetics, invasion genetics, and design of protected areas.
Evaluating Signatures of Glacial Refugia for North Atlantic Benthic Marine Taxa
A goal of phylogeography is to relate patterns of genetic differentiation to potential historical geographic isolating events. Quaternary glaciations, particularly the one culminating in the Last Glacial Maximum ~21 ka (thousands of years ago), greatly affected the distributions and population sizes of temperate marine species as their ranges retreated southward to escape ice sheets. Traditional genetic models of glacial refugia and routes of recolonization include these predictions: low genetic deversity in formerly glaciated areas, with a small number of alleles/haplotypes dominating disproportionately large areas, and high diversity including \"private\" alleles in glacial refugia. In the Northern Hemisphere, low diversity in the north and high diversity in the south are expected. This simple model does not account for the possibility of populations surviving in relatively small northern periglacial refugia. If these periglacial populations experienced extreme bottlenecks, they could have the low genetic diversity expected in recolonized areas with no refugia, but should have more endemic diversity (private alleles) than recently recolonized areas. This review examines evidence of putative glacial refugia for eight benthic marine taxa in the temperate North Atlantic. All data sets were reanalyzed to allow direct comparisons between geographic patterns of genetic diversity and distribution of particular clades and haplotypes including private alleles. We contend that for marine organisms the genetic signatures of northern periglacial and southern refugia can be distinguished from one another. There is evidence for several periglacial refugia in northern latitudes, giving credence to recent climatic reconstructions with less extensive glaciation.
Mitochondrial DNA: a promising tool for characterising the population of the Tiúba stingless bee, Melipona fasciculata (Apidae, Meliponini)
The Melipona fasciculata popularly known as Tiúba, is a specie of stingless bee that is distributed in the north of Brazil, over-represented in Maranhão State. This bee is of great importance to stingless bees (SLB) beekeepers, as it produces a large quantity of honey with an excellent taste. The genetic diversity of the Tiúba populations was examined with molecular approach using the mitochondrial DNA (mtDNA) marker. A total of 30 samples from cities in Maranhão State were analysed for the mtDNA intergenic region located between the cytochrome c oxidase I (COI). The molecular analyses identified 8 haplotypes, 3 of which are shared between locations, where the commercialization of beehives is very common and the commercialization of beehives is very common. The populations of Imperatriz and São Bento have the highest diversity indices, and the neutrality tests showed that the populations might be expansion. The fixation index of the study populations showed a high differentiation rate of 0.6218. These Tiúba populations exhibit a high level of genetic structuring, as well as potentially being in a population expansion phase.
Genomic Signatures Reveal New Evidences for Selection of Important Traits in Domestic Cattle
We investigated diverse genomic selections using high-density single nucleotide polymorphism data of five distinct cattle breeds. Based on allele frequency differences, we detected hundreds of candidate regions under positive selection across Holstein, Angus, Charolais, Brahman, and N'Dama. In addition to well-known genes such as KIT, MC1R, ASIP, GHR, LCORL, NCAPG, WIF1, and ABCA12, we found evidence for a variety of novel and less-known genes under selection in cattle, such as LAP3, SAR1B, LRIG3, FGF5, and NUDCD3. Selective sweeps near LAP3 were then validated by next-generation sequencing. Genome-wide association analysis involving 26,362 Holsteins confirmed that LAP3 and SAR1B were related to milk production traits, suggesting that our candidate regions were likely functional. In addition, haplotype network analyses further revealed distinct selective pressures and evolution patterns across these five cattle breeds. Our results provided a glimpse into diverse genomic selection during cattle domestication, breed formation, and recent genetic improvement. These findings will facilitate genome-assisted breeding to improve animal production and health.
Sanguina nivaloides and Sanguina aurantia gen. et spp. nov. (Chlorophyta): the taxonomy, phylogeny, biogeography and ecology of two newly recognised algae causing red and orange snow
ABSTRACT Melting snowfields in polar and alpine regions often exhibit a red and orange colouration caused by microalgae. The diversity of these organisms is still poorly understood. We applied a polyphasic approach using three molecular markers and light and electron microscopy to investigate spherical cysts sampled from alpine mountains in Europe, North America and South America as well as from both polar regions. Molecular analyses revealed the presence of a single independent lineage within the Chlamydomonadales. The genus Sanguina is described, with Sanguina nivaloides as its type. It is distinguishable from other red cysts forming alga by the number of cell wall layers, cell size, cell surface morphology and habitat preference. Sanguina nivaloides is a diverse species containing a total of 18 haplotypes according to nuclear ribosomal DNA internal transcribed spacer 2, with low nucleotide divergence (≤3.5%). Based on molecular data we demonstrate that it has a cosmopolitan distribution with an absence of geographical structuring, indicating an effective dispersal strategy with the cysts being transported all around the globe, including trans-equatorially. Additionally, Sanguina aurantia is described, with small spherical orange cysts often clustered by means of mucilaginous sheaths, and causing orange blooms in snow in subarctic and Arctic regions. Red and orange spherical cysts causing snow colouration across several continents were investigated with regards to their geographic distribution, ecology, ultrastructure and phylogeny; the cosmopolitan distribution of a new independent lineage Sanguina within the Chlamydomonadales was molecularly confirmed.
Molecular analysis of knockdown resistance (kdr) mutations in the voltage-gated sodium channel gene of Aedes aegypti populations from Saudi Arabia
Background The Aedes aegypti  mosquito is the primary vector for dengue, chikungunya, yellow fever and Zika viruses worldwide. The first record of Ae. aegypti in southwestern Saudi Arabia was in 1956. However, the first outbreak and cases of dengue fever were reported in 1994, and cases have increased in recent years. Vector control for Ae. aegypti mainly uses pyrethroid insecticides in outdoor and indoor space spraying. The constant use of pyrethroids has exerted intense selection pressure for developing target-site mutations in the voltage-gated sodium channel ( vgsc ) gene in Ae. Aegypti against pyrethroids—mutations that have led to knockdown resistance ( kdr ). Methods Aedes aegypti  field populations from five regions (Jazan, Sahil, Makkah, Jeddah and Madinah) of southwestern Saudi Arabia were genotyped for known  kdr  mutations in domains IIS6 and IIIS6 of the vgsc gene using polymerase chain reaction (PCR) amplification and sequencing. We estimated the frequency of kdr mutations and genotypes from Saudi Arabia as well as from other countries, Thailand, Myanmar (Southeast Asia) and Uganda (East Africa). We constructed haplotype networks to infer the evolutionary relationships of these gene regions. Results The three known kdr mutations, S989P, V1016G (IIS6) and F1534C (IIIS6), were detected in all five regions of Saudi Arabia. Interestingly, the triple homozygous wild genotype was reported for the first time in two individuals from the highlands of the Jazan region and one from the Al-Quoz, Sahil region. Overall, nine genotypes comprising four haplotypes were observed in southwestern Saudi Arabia. The median-joining haplotype networks of eight populations from Saudi Arabia, Southeast Asia and East Africa for both the IIS6 and IIIS6 domains revealed that haplotype diversity was highest in Uganda and in the Jazan and Sahil regions of Saudi Arabia, whereas haplotype diversity was low in the Jeddah, Makkah and Madinah regions. Median-joining haplotype networks of both domains indicated selection acting on the kdr -mutation containing haplotypes in Saudi Arabia. Conclusions The presence of wild type haplotypes without any of the three kdr mutations, i.e. that are fully susceptible, in Saudi Arabia indicates that further consideration should be given to insecticide resistance management strategies that could restore pyrethroid sensitivity to the populations of Ae. aegypti in Saudi Arabia as part of an integrative vector control strategy. Graphical Abstract
Molecular detection and characterisation of Mycoplasma species in community owned dogs of Kerala, a South Indian State
Haemotropic mycoplasmas (haemoplasmas) are obligate epierythrocytic bacteria that infect a wide range of vertebrate hosts. The molecular characterisation of  organisms in dogs has not previously been attempted from India. Hence, in the present study, the molecular characterisation of  spp. in dogs of different zones of Kerala was attempted using gene. An overall prevalence of 18% for was detected. The NCBI-BLAST analysis of all the selected sequences revealed > 99% identity with the sequences of  The phylogenetic analysis revealed clustering of  and in a single clade indicating low genetic variability. It was further supported by the genetic distance data and haplotype analysis.
HapNetworkView: a tool for haplotype network exploration and visualization
Background Haplotype networks are useful for investigating the genealogical relationships among haplotypes and have been extensively used in molecular evolution and population genetic studies. However, existing tools for visualizing haplotype networks lack comprehensive functionalities for data exploration and layout adjustments. Therefore, there is a need for a useful tool capable of constructing and visualizing haplotype networks, facilitating the exploration of data, particularly with datasets with large sample sizes. Results We present HapNetworkView, a user-friendly tool that facilitates the construction and interactive visualization of haplotype networks, enabling users to explore haplotypes and mutation information effectively. HapNetworkView offers both automatic optimization and manual adjustment for haplotype network layouts. Additionally, HapNetworkView supports various input and output formats, as well as color customization. Conclusions These comprehensive functionalities collectively satisfy various needs of users in haplotype network analysis, making HapNetworkView a valuable tool.