Population Genetic Characteristics Research Articles

Differences in Albizia odoratissima genetic diversity between Hainan Island and mainland populations in China.

This study aimed at exploring unique population genetic characteristics of Albizia odoratissima (Linn. f) Benth on Hainan Island to provide a scientific basis for its rational utilization and protection. It analyzed the genetic diversity and structure of 280 individuals from 10 subpopulations of A. odoratissima from Hainan Island and Baise City using 16 expression sequence markers - simple sequence repeat markers. The genetic diversity of Hainan population (I = 0.7290, He = 0.4483) was lower than that of the Baise population (I = 0.8722, He = 0.5121). Compared with the Baise population (Nm = 2.0709, FST = 0.1077), the Hainan Island population (Nm = 1.7519, FST = 0.1249) exhibited lower gene flow and higher degree of genetic differentiation. Molecular variance and genetic differentiation analyses showed that the main variation originated from individuals within the subpopulation. There were significant differences in the genetic structure between Hainan and Baise populations. It grouped according to geographical distance, consistent with the Mantel test results (R2 = 0.77, p = 0.001). In conclusion, the genetic diversity of the island A. odoratissima population was lower than that distributed on land, the two populations exhibited obvious genetic structure differences. Both the degrees of inbreeding and genetic differentiation were higher in the island population than in the land population.

Population Genomics of Commercial Fish Sebastes schlegelii of the Bohai and Yellow Seas (China) Using a Large SNP Panel from GBS.

Sebastes schlegelii is one of the most commercially important marine fish in the northwestern Pacific. However, little information about the genome-wide genetic characteristics is available for S. schlegelii individuals from the Bohai and Yellow Seas. In this study, a total of 157,778, 174,480, and 188,756 single-nucleotide polymorphisms from Dalian (DL), Yantai (YT), and Qingdao (QD) coastal waters of China were, respectively, identified. Sixty samples (twenty samples per population) were clustered together, indicating shallow structures and close relationships with each other. The observed heterozygosity, expected heterozygosity, polymorphism information content, and nucleotide diversity ranged from 0.14316 to 0.17684, from 0.14035 to 0.17145, from 0.20672 to 0.24678, and from 7.63 × 10-6 to 8.77 × 10-6, respectively, indicating the slight difference in genetic diversity among S. schlegelii populations, and their general genetic diversity was lower compared to other marine fishes. The population divergence showed relatively low levels (from 0.01356 to 0.01678) between S. schlegelii populations. Dispersing along drifting seaweeds, as well as the ocean current that flows along the western and northern coasts of the Yellow Sea and southward along the eastern coast of China might be the major reasons for the weak genetic differentiation. These results form the basis of the population genetic characteristics of S. schlegelii based on GBS (Genotyping by Sequencing). In addition to basic population genetic information, our results provid a theoretical basis for further studies aimed at protecting and utilizing S. schlegelii resources.

Prospects for use of genetic tagging technology in animal husbandry

The efficiency of DNA extraction with using different extraction methods: from the cartilage tissue of the outer ear and the leukocyte fraction of whole blood of cattle, followed by an assessment of the possible prospects for the use of “genetic tagging” technology in animal husbandry has been compared in the work. It was established that according to the results of the research the highest concentration of DNA (146,26±13,180 ng/μl at p < 0,001) was obtained in samples from ear tissues when using the method of precipitation with reagents compared to isolating DNA from the leukocyte fraction of whole blood using highly eff ective methods extraction of genomic deoxyribonucleic acid on magnetic particles (22,80±3,138 ng/μl) and on columns (39,46±8,941 ng/μl). It was found when assessing DNA contamination with polypeptides that despite the fact that when using diff erent extraction methods, the ratio of optical densities at the corresponding absorption wavelengths A260/A280 was close to the optimal ~1,8. The smallest scatter of measurement values was obtained in DNA samples from earmarks tissue 1,89±0,008. In a subsequent comparison of available technologies for taking ear pluck tissue samples used for genetic research (population genetic characterization, genomic analysis, etc.), the FlexoPlusGeno “genetic tagging” system turned out to be the most preferable. In this case, the resulting ear pluck tissue sample is correlated with corresponding ear visual or RFID tags, which creates a “link” of the biomaterial to a specific animal with the ability to track it throughout its life. The technology under consideration is applicable for collecting and storing samples of cartilage tissue obtained by ear plucking from cattle, small ruminants, pigs and deer.

Genomic characteristics of clinical non-toxigenic Vibrio cholerae isolates in Switzerland: a cross-sectional study.

Although non-toxigenicVibrio choleraelack thectxABgenes encoding cholera toxin, they can cause diarrhoeal disease and outbreaks in humans. In Switzerland,V. choleraeis a notifiable pathogen and all clinical isolates are analysed at the National Reference Laboratory for Enteropathogenic Bacteria and Listeria. Up to 20 infections are reported annually. In this study, we investigated the population structure and genetic characteristics of non-toxigenicV. choleraeisolates collected over five years. V. choleraeisolates were serotyped and non-toxigenic isolates identified using actxA-specific PCR. Following Illumina whole-genome sequencing, genome assemblies were screened for virulence and antibiotic resistance genes. Phylogenetic analyses were performed in the context of 965 publicly availableV. choleraegenomes. Out of 33V. choleraeinfections reported between January 2017 and January 2022 in Switzerland, 31 were caused byctxA-negative isolates. These non-toxigenic isolates originated from gastrointestinal (n = 29) or extraintestinal (n = 2) sites. They were phylogenetically diverse and belonged to 29 distinct sequence types. Two isolates were allocated to the lineage L3b, actxAB-negative buttcpA-positive clade previously associated with regional outbreaks. The remaining 29 isolates were placed in lineage L4, which is associated with environmental strains. Genes or mutations associated with reduced susceptibility to the first-line antibiotics fluoroquinolones and tetracyclines were identified in 11 and 3 isolates, respectively. One isolate was predicted to be multidrug resistant. V. choleraeinfections in Switzerland are rare and predominantly caused by lowly virulentctxAB-negative andtcpA-negative strains. AsV. choleraeis not endemic in Switzerland, cases are assumed to be acquired predominantly during travel. This assumption was supported by the phylogenetic diversity of the analysed isolates.

Copy number variations within fibroblast growth factor 13 gene influence growth traits and alternative splicing in cattle

Previous researches revealed a copy number variation (CNV) region in the bovine fibroblast growth factor 13 (FGF13) gene. However, its effects remain unknown. This study detected the various copy number types in seven Chinese cattle breeds and analysed their population genetic characteristics and effects on growth traits and transcription levels. Copy number Loss was more frequent in Caoyuan Red cattle and Xianan cattle than in the other breeds. Association analysis between CNV and growth traits of Qinchuan indicated that the CNV was significantly related to chest depth, hip width and hucklebone width (P < 0.05). Additionally, the growth traits of individuals with copy number Loss were significantly inferior to those with copy number Gain or Median (P < 0.05). Besides, we found two splicing isoforms, AS1 and AS2, in FGF13 gene, which resulted from alternative 5′ splicing sites of intron 1. These isoforms showed varied expression levels in various tissues. Moreover, CNV was significantly and negatively associated with the mRNA expression of AS1 (r = −0.525, P < 0.05). The CNVs in bovine FGF13 gene negatively regulated growth traits and gene transcription. These observations provide new insights into bovine FGF13 gene, delivering potentially useful information for future Chinese cattle breeding programs.

Hereditary Thoracic Aortic Diseases.

Advances in both imaging techniques and genetics have led to the recognition of a wide variety of aortic anomalies that can be grouped under the term 'hereditary thoracic aortic diseases'. The present review aims to summarize this very heterogeneous population's clinical, genetic, and imaging characteristics and to discuss the implications of the diagnosis for clinical counselling (on sports activity or pregnancy), medical therapies and surgical management.

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.

Population genetic characteristics of free-living domestic cats, Felis catus L., 1758, of Russky Island (Peter the Great Bay, Primorsky Krai)

The enormous infl uence of free-living populations of the domestic cat (Felis catus L., 1758) on the wild fauna of small animals throughout the world provides the basis for a careful multilateral study of such populations with a view to their subsequent control, including their genetic structure. A description of the genetic profi le of the free-living population of domestic cats of Russky Island is given. It has been shown that the island population is genetically almost identical to the mainland population of Vladivostok. The exception is a statistically signifi cantly lower proportion of piebald cats on Russky Island (51.8 ± 4.8% versus 63.8 ± 2.0%, p &lt; 0.02). This indicates a common origin for these populations. Due to their recent emergence (probably no more than 160 years ago) and low level of isolation, the populations experienced little genetic shift relative to each other. Similar data were obtained earlier for other pairs of settlements (urban- rural) in Primorsky Krai. A comparative analysis of the available data on the genetic diff erentiation of adjacent urban and rural populations of free-living domestic cats was carried out. The possible connection of genetic variability with the advantage in hunting activity of cats is discussed.

Genomic Dissection through Whole-Genome Resequencing of Five Local Pig Breeds from Shanghai, China

China has rich genetic resources of local pig breeds. In this study, whole-genome resequencing was performed on five Shanghai local pig breeds, aiming to analyze their population genetic structure and unique genomic characteristics. Tens of millions of single nucleotide variants were obtained through the resequencing of a total of 150 individual pigs from five local pig breeds (Meishan, Fengjing, Shawutou, Pudong White, and Shanghai White) after mapping them with the pig reference genome of Sus scrofa 11.1. The results of admixture structure analysis also clearly demonstrated the genetic differences between the Shanghai local pig breeds and the three commercial pig breeds (Duroc, Landrace, and Yorkshire). The genetic infiltration of Landrace and Yorkshire pig breeds in the SHW breed was detected, which is consistent with the early history of crossbreeding in this breed. Selective sweep analysis between four indigenous Shanghai pig breed populations and three commercial pig breed populations identified 270 and 224 genes with selective signatures in the commercial and indigenous Shanghai pig populations, respectively. Six genes (TGS1, PLAG1, CHCHD7, LCORL, TMEM68, and TMEM8B) were found to be associated with animal growth in the commercial pig population through gene enrichment and protein–protein interaction analysis. In contrast, the MSRB3 gene in the indigenous Shanghai pig population was significantly under selection, which correlated with the long pendulous ear phenotype of the indigenous Shanghai pig population. In conclusion, this study is the first genomic profiling of five representative local pig breeds in Shanghai, which provides molecular genetic data and foundations for better conservation and utilization of local pig breed resources in Shanghai, China.

Population genomics provides insights into the genetic diversity and adaptation of the Pieris rapae in China.

The cabbage white butterfly (Pieris rapae), a major agricultural pest, has become one of the most abundant and destructive butterflies in the world. It is widely distributed in a large variety of climates and terrains of China due to its strong adaptability. To gain insight into the population genetic characteristics of P. rapae in China, we resequenced the genome of 51 individuals from 19 areas throughout China. Using population genomics approaches, a dense variant map of P. rapae was observed, indicating a high level of polymorphism that could result in adaptation to a changing environment. The feature of the genetic structure suggested considerable genetic admixture in different geographical groups. Additionally, our analyses suggest that physical barriers may have played a more important role than geographic distance in driving genetic differentiation. Population history showed the effective population size of P. rapae was greatly affected by global temperature changes, with mild periods (i.e., temperatures warmer than those during glaciation but not excessively hot) leading to an increase in population size. Furthermore, by comparing populations from south and north China, we have identified selected genes related to sensing temperature, growth, neuromodulation and immune response, which may reveal the genetic basis of adaptation to different environments. Our study is the first to illustrate the genetic signatures of P. rapae in China at the population genomic level, providing fundamental knowledge of the genetic diversity and adaptation of P. rapae.

Genomic evolution of island birds from the view of the Swinhoe's pheasant (Lophura swinhoii).

Island endemic birds account for the majority of extinct vertebrates in the past few centuries. To date, the evolutionary characteristics of island endemic bird's is poorly known. In this research, we de novo assembled a high-quality chromosome-level reference genome for the Swinhoe's pheasant, which is a typical endemic island bird. Results of collinearity tests suggest rapid ancient chromosome rearrangement that may have contributed to the initial species radiation within Phasianidae, and a role for the insertions of CR1 transposable elements in rearranging chromosomes in Phasianidae. During the evolution of the Swinhoe's pheasant, natural selection positively selected genes involved in fecundity and body size functions, at both the species and population levels, which reflect genetic variation associated with island adaptation. We further tested for variation in population genomic traits between the Swinhoe's pheasant and its phylogenetically closely related mainland relative the silver pheasant, and found higher levels of genetic drift and inbreeding in the Swinhoe's pheasant genome. Divergent demographic histories of insular and mainland bird species during the last glacial period may reflect the differing impact of insular and continental climates on the evolution of species. Our research interprets the natural history and population genetic characteristics of the insular endemic bird the Swinhoe's pheasant, at a genome-wide scale, provides a broader perspective on insular speciation, and adaptive evolution and contributes to the genetic conservation of island endemic birds.

Population genetics of Artemia urmiana species complex (Crustacea, Anostraca): A group with asymmetrical dispersal and gene flow mediated by migratory waterfowl

Bird-mediated dispersal of resting eggs is the main mechanism for Artemia dispersal among catchments. The bisexual populations of Artemia urmiana species complex, which is here considered to be a collection of Artemia genetically close to the so-called “Western Asian Lineage”, are mostly distributed in central and western Asia (i.e., in regions falling into the Central Asian Flyway of migratory birds) and live in diversified habitats. Little is known about the genetic relationships among these populations. Aiming to understand the population genetic characteristics and the roles of migratory birds on the dispersal and gene flow of this Artemia group, we evaluated the genetic diversity, genetic differentiation, and gene flow among 14 populations, with their altitudes ranging from 540 to 4870 m above sea level, using 13 microsatellite markers. Almost all populations exhibited high genetic diversity and heterozygote excess, which may be a consequence of combined effects of dispersal and hybridization. The global genetic differentiation (FST) value was 0.092, the pairwise FST values were 0.003–0.246. Discriminant analysis of principal components identified three genetic clusters, consisting of Urmia Lake (Iran), Zhundong (Xinjiang, China), and 12 Qinghai-Tibet Plateau populations, respectively. The among-population genetic differentiation seems to be a consequence of isolation by distance and adaptation to diversified habitats induced by altitudinal gradient. Historical gene flows are asymmetrical, and show an evolutionary source-sink dynamics, with Jingyu Lake (Xinjiang, China) population being the major source. These results support our hypothesis that in Qinghai-Tibet Plateau and surrounding areas the bird-mediated dispersal of Artemia may be biased towards from north to south and/or from higher altitude to lower altitude.

Population Genetic Characterization of the Pear Pest, Cacopsylla jukyungi (Kwon, 1983) (Hemiptera: Psyllidae), Using Novel Microsatellite Markers

The pear pest, Cacopsylla jukyungi (Hemiptera: Psyllidae), is the most damaging insect to commercial pears in South Korea. An assessment of the population genetic characteristics of the species will raise the potential of effective control. In the present study, we developed eight microsatellite markers specific to C. jukyungi and genotyped 132 individuals collected from 11 localities throughout South Korea. Populations showed lower observed heterozygosity than expected heterozygosity and slightly or highly positive values of inbreeding coefficients, suggesting that C. jukyungi is subjected to inbreeding. A strong dependence on commercial pear trees throughout the whole life cycle, even during overwintering, and a nationwide targeting of the overwintered adults are likely contributors to such heterozygosity deficiency. On the other hand, population analyses consistently indicated strong gene flow among populations, implying the presence of persistent factors that have facilitated this process. The nationwide expansion of pear orchards and the replacement with a popular new cultivar during the last 50 years, which may have accompanied the spread of C. jukyungi-bearing pear grafts and scions, are likely causes of such facilitated dispersal. Thus, a management strategy against unintended anthropogenic dispersal of the pear psyllid will be required for better control of C. jukyungi.

Population genetic characterization of (Aedes albopictus) mosquitoes (Diptera: Culicidae) from the Yangtze River Basin of China based on rDNA-ITS2.

Aedes albopictus is an important vector of many mosquito-borne viral diseases, including dengue fever and Zika. In recent years, it has spread and colonized tropical, subtropical and temperate regions worldwide. Monitoring of Ae. albopictus population dynamics is an important tool for early warning of mosquito-borne infections. Because the genetic diversity and genetic structure of natural populations are the genetic bases of population dynamics, studies of population genetics can reveal the origin, differentiation and dispersal characteristics of Ae. albopictus populations. Then, their evolutionary potential and environmental adaptability can be analyzed, providing a theoretical basis for the formulation of accurate Ae. albopictus surveillance and integrated control programs. In 2018, 552 Ae. albopictus larvae were collected during an invasive mosquito species surveillance project in China's Yangtze River Basin. Morphological analysis was performed to assign the adult mosquitoes to species, and then the genetic marker ITS2 was amplified and sequenced. There were 179 haplotypes among 552 ITS2 sequences. In total, 155/179 (86.59%) haplotypes were specific to individual populations, and 24/179 (13.41%) haplotypes were shared by populations. Hap4 (126), Hap7 (43), and Hap16 (34) were the most numerous haplotypes and the most widely distributed. The overall Hd was 0.928, π was 0.031, the mean nucleotide difference number (K) was 7.255, and the number of segregating sites was 169. TCS network maps mainly showed a single star-like scattered distribution. According to geographical location, there were no obvious haplotype groups, and the haplotypes were intricately connected. The genetic diversity of Ae. albopictus populations in the Yangtze River Basin was high. The molecular variance observed in the populations of Ae. albopictus mainly occurred among individuals within populations, accounting for 98.79% of the total, while that among populations accounted for only 1.21% of the total. Only the populations of Ae. albopictus in the Chongqing and Sichuan regions showed a moderate degree of population genetic differentiation, while genetic differentiation between the other regions were small, gene exchange was very common, and genetic differentiation within populations was minimal. According to this study, the genetic diversity of Ae. albopictus populations in the Yangtze River Basin is high, the genetic differentiation among populations is small, and gene exchange is common. In addition, frequent interregional exchange exacerbates the abnormal spread of vectors. This study highlighted the potential spread route of the vector Ae. albopictus in the Yangtze River Basin. There are three potential dispersal routes for Ae. albopictus populations in the Yangtze River Basin. The findings could be helpful for effective surveillance and early warning of Ae. albopictus vectors.

Insecticide resistance of Anopheles sinensis after elimination of malaria in Henan Province, China

BackgroundHistorically, malaria due to Plasmodium vivax has been epidemic in Henan Province, China, with Anopheles sinensis as the main vector. The most effective measures to prevent malaria transmission are based on vector control through the use of insecticides. However, insecticides exert a strong selective pressure on mosquito populations for insecticide resistance. The aim of this study was to investigate the susceptibility profile and population genetic characteristics of An. sinensis to provide basic data and scientific guidance for the study of resistance mechanisms and the control of An. sinensis in Henan Province.MethodsAdult Anopheles mosquitoes were collected at sites near local farmers' sheepfolds, pigsties and/or cowsheds located in Pingqiao, Xiangfu, Xiangcheng and Tanghe counties/districts of Henan Province during July–September 2021 for insecticide susceptibility testing. Molecular identification of collected mosquitoes as belonging to genus Anopheles was by PCR, and the frequencies of mutations in the knockdown resistance gene (kdr) and acetylcholinesterase-1 gene (ace-1) were detected using gene amplification. The mitochondrial DNA cytochrome oxidase subunit I (COI) gene was amplified in deltamethrin-resistant and deltamethrin-sensitive mosquitoes to analyze the genetic evolutionary relationship.ResultsA total of 1409 Anopheles mosquitoes were identified by molecular identification, of which 1334 (94.68%) were An. sinensis, 28 (1.99%) were An. yatsushiroensis, 43 (3.05%) were An. anthropophagus and four (0.28%) were An. belenrae. The 24-h mortality rates of An. sinensis in Pingqiao, Tanghe, Xiangcheng and Xiangfu counties/districts exposed to deltamethrin were 85.85%, 25.38%, 29.73% and 7.66%, respectively; to beta-cyfluthrin, 36.24%, 70.91%, 34.33% and 3.28%, respectively; to propoxur, 68.39%, 80.60%, 37.62% and 9.29%, respectively; and to malathion, 97.43%, 97.67%, 99.21% and 64.23%, respectively. One mutation, G119S, was detected in the ace-1 gene. The frequencies of the main genotypes were 84.21% of specimens collected in Xiangfu (G/S), 90.63% of speciments collected in Xiangcheng (G/G) and 2.44% of speciments collected in Tanghe (S/S). Significantly higher G119S allele frequencies were observed in both propoxur- and malathion-resistant mosquitoes than in their sensitive counterparts in the Tanghe population (P < 0.05). Three mutations, L1014F (41.38%), L1014C (9.15%) and L1014W (0.12%), were detected in the kdr gene. The genotypes with the highest frequency in the populations of An. sinensis in Xiangfu and Tanghe were the mutant TTT (F/F) and wild-type TTG (L/L), at 67.86% (57/84) and 74.29% (52/70), respectively. In Pingqiao and Xiangfu, higher frequencies of the L1014F allele and lower frequencies of the L1014C allele were observed in mosquitoes resistant for beta-cyfluthrin than in those which were sensitive for this insecticide (P < 0.05). The results of Tajima's D and of Fu and Li's D and F were not significantly negative (P > 0.10), and each haplotype was interlaced and did not form two distinct branches.ConclusionsHigh resistance to pyrethroids and propoxur was observed at four sites, but the resistance to malathion varied according to the location. Anopheles belenrae and the L1014W (TGG) mutation in An. sinensis were first discovered in Henan Province. The deltamethrin-resistant and deltamethrin-sensitive mosquito populations showed no genetic differentiation. The generation of resistance might be the result of the combination of multiple factors.Graphical

Evaluation of the evolutionary genetics and population structure of Culex pipiens pallens in Shandong province, China based on knockdown resistance (kdr) mutations and the mtDNA-COI gene

BackgroundMosquitoes are important vectors for a range of diseases, contributing to high rates of morbidity and mortality in the human population. Culex pipiens pallens is dominant species of Culex mosquito in northern China and a major vector for both West Nile virus and Bancroftian filariasis. Insecticide application were largely applied to control the mosquito-mediated spread of these diseases, contributing to increasing rates of resistance in the mosquito population. The voltage-gated sodium channel (Vgsc) gene is the target site of pyrethroids, and mutations in this gene cause knockdown resistance (kdr). While these kdr mutations are known to be critical to pyrethroid resistance, their evolutionary origins remain poorly understood. Clarifying the origins of these mutations is potential to guide further vector control and disease prevention efforts. Accordingly, the present study was designed to study the evolutionary genetics of kdr mutations and their association with the population structure of Cx. p. pallens in Shandong province, China.MethodsAdult Culex females were collected from Shandong province and subjected to morphological identification under a dissection microscope. Genomic DNA were extracted from the collected mosquitoes, the Vgsc gene were amplified via PCR and sequenced to assess kdr allele frequencies, intron polymorphisms, and kdr codon evolution. In addition, population genetic diversity and related population characteristics were assessed by amplifying and sequencing the mitochondrial cytochrome C oxidase I (COI) gene.ResultsTotally, 263 Cx. p. pallens specimens were used for DNA barcoding and sequencing analyses to assess kdr allele frequencies in nine Culex populations. The kdr codon L1014 in the Vgsc gene identified two non-synonymous mutations (L1014F and L1014S) in the analyzed population. These mutations were present in the eastern hilly area and west plain region of Shandong Province. However, only L1014F mutation was detected in the southern mountainous area and Dongying city of Shandong Province, where the mutation frequency was low. Compared to other cities, population in Qingdao revealed significant genetic differentiation. Spatial kdr mutation patterns are likely attributable to some combination of prolonged insecticide-mediated selection coupled with the genetic isolation of these mosquito populations.ConclusionsThese data suggest that multiple kdr alleles associated with insecticide resistance are present within the Cx. p. pallens populations of Shandong Province, China. The geographical distributions of kdr mutations in this province are likely that the result of prolonged and extensive insecticide application in agricultural contexts together with frequent mosquito population migrations. In contrast, the low-frequency kdr mutation detected in central Shandong Province populations may originate from the limited selection pressure in this area and the relative genetic isolation. Overall, the study compares the genetic patterns revealed by a functional gene with a neutral marker and demonstrates the combined impact of demographic and selection factors on population structure.

Population genetic characteristics of citrus tristeza virus from wild mandarins in the Nanling Mountains of China

Population genetic characteristics of citrus tristeza virus from wild mandarins in the Nanling Mountains of China

Population genetic characteristics of Aedes aegypti in 2019 and 2020 under the distinct circumstances of dengue outbreak and the COVID-19 pandemic in Yunnan Province, China.

Introduction: Since Aedes aegypti invaded Yunnan Province in 2002, its total population has continued to expand. Shi et al. used microsatellite and mitochondrial molecular markers to study the Ae. aegypti populations in Yunnan Province in 2015 and 2016, found that it showed high genetic diversity and genetic structure. However, there are few studies on the population genetic characteristics of Ae. aegypti in Yunnan Province under different levels of human intervention. This study mainly used two common types of molecular markers to analyze the genetic characteristics of Ae. aegypti, revealing the influence of different input, prevention and control pressures on the genetic diversity and structure of this species. Understanding the genetic characteristics of Ae. aegypti populations and clarifying the diversity, spread status, and source of invasion are essential for the prevention, control and elimination of this disease vector. Methods: We analyzed the genetic diversity and genetic structure of 22 populations sampled in Yunnan Province in 2019 and 17 populations sampled in 2020 through nine microsatellite loci and COI and ND4 fragments of mitochondrial DNA. In 2019, a total of 22 natural populations were obtained, each containing 30 samples, a total of 660 samples. In 2020, a total of 17 natural populations were obtained. Similarly, each population had 30 samples, and a total of 510 samples were obtained. Results: Analysis of Ae. aegypti populations in 2019 and 2020 based on microsatellite markers revealed 67 and 72 alleles, respectively. The average allelic richness of the populations in 2019 was 3.659, while that in 2020 was 3.965. The HWE analysis of the 22 populations sampled in 2019 revealed significant departure only in the QSH-2 population. The 17 populations sampled in 2020 were all in HWE. The average polymorphic information content (PIC) values were 0.546 and 0.545, respectively, showing high polymorphism. The average observed heterozygosity of the 2019 and 2020 populations was 0.538 and 0.514, respectively, and the expected average heterozygosity was 0.517 and 0.519, showing high genetic diversity in all mosquito populations. By analyzing the COI and ND4 fragments in the mitochondrial DNA of Ae. aegypti, the populations sampled in 2019 had a total of 10 COI haplotypes and 17 ND4 haplotypes. A total of 20 COI haplotypes were found in the populations sampled in 2020, and a total of 24 ND4 haplotypes were obtained. STRUCTURE, UPGMA and DAPC cluster analyses and a network diagram constructed based on COI and ND4 fragments showed that the populations of Ae. aegypti in Yunnan Province sampled in 2019 and 2020 could be divided into two clusters. At the beginning of 2020, due to the impact of COVID-19, the flow of goods between the port areas of Yunnan Province and neighboring countries was reduced, and the sterilization was more effective when goods enter the customs, leading to different immigration pressures on Ae. aegypti population in Yunnan Province between 2019 and 2020, the source populations of the 2019 and 2020 populations changed. Mantel test is generally used to detect the correlation between genetic distance and geographical distance, the analysis indicated that population geographic distance and genetic distance had a moderately significant correlation in 2019 and 2020 (2019: p < 0.05 R2 = 0.4807, 2020: p < 0.05 R2 = 0.4233). Conclusion: Ae. aegypti in Yunnan Province maintains a high degree of genetic diversity. Human interference is one reason for the changes in the genetic characteristics of this disease vector.

Genetic Structure Analysis of 155 Transboundary and Local Populations of Cattle (Bos taurus, Bos indicus and Bos grunniens) Based on STR Markers.

Every week, 1-2 breeds of farm animals, including local cattle, disappear in the world. As the keepers of rare allelic variants, native breeds potentially expand the range of genetic solutions to possible problems of the future, which means that the study of the genetic structure of these breeds is an urgent task. Providing nomadic herders with valuable resources necessary for life, domestic yaks have also become an important object of study. In order to determine the population genetic characteristics, and clarify the phylogenetic relationships of modern representatives of 155 cattle populations from different regions of the world, we collected a large set of STR data (10,250 individuals), including unique native cattle, 12 yak populations from Russia, Mongolia and Kyrgyzstan, as well as zebu breeds. Estimation of main population genetic parameters, phylogenetic analysis, principal component analysis and Bayesian cluster analysis allowed us to refine genetic structure and provided insights in relationships of native populations, transboundary breeds and populations of domestic yak. Our results can find practical application in conservation programs of endangered breeds, as well as become the basis for future fundamental research.

Genetic differentiation and genetic structure of mixed-ploidy Camellia hainanica populations.

Camellia hainanica, which is common in China's Hainan Province, is an important woody olive tree species. Due to many years of geographic isolation, C. hainanica has not received the attention it deserves, which limits the exploitation of germplasm resources. Therefore, it is necessary to study population genetic characteristics for further utilization and conservation of C. hainanica. In this study, 96 individuals in six wild Camellia hainanica populations were used for ploidy analysis of the chromosome number, and the genetic diversity and population structure were investigated using 12 pairs of SSR primers. The results show complex ploidy differentiation in C. hainanica species. The ploidy of wild C. hainanica includes tetraploid, pentaploid, hexaploid, heptaploid, octoploid and decaploid species. Genetic analysis shows that genetic diversity and genetic differentiation among populations are low. Populations can be divided into two clusters based on their genetic structure, which matches their geographic location. Finally, to further maintain the genetic diversity of C. hainanica, ex-situ cultivation and in-situ management measures should be considered to protect it in the future.