Coefficient Of Genetic Differentiation Research Articles

SSR marker-based genetic diversity and structure analyses of Camellia nitidissima var. phaeopubisperma from different populations.

Camellia nitidissima var. phaeopubisperma is a variety in the section Chrysantha of the genus Camellia of the family Theaceae which is native to Fangchenggang, Guangxi, China. To date, the genetic diversity and structure of this variety remains to be understood. In the present study, eight simple sequence repeat (SSR) molecular markers previously screened were used to analyze the genetic diversity and structure of C. nitidissima var. phaeopubisperma natural populations from 14 growing areas in China, so as to determine the influence of environmental changes on genetic variations and provide the basis for introduction and selection of suitable growing sites of that variety. Our results show that, for the eight SSR loci, the observed numbers of alleles per locus (Na) and the effective numbers of alleles per locus (Ne) were nine and 3.206, respectively on average, and the Ne was lower than the Na for all loci; the observed heterozygosity (Ho) was lower than the expected heterozygosity (He). For all the eight loci, the fixation index (F) was greater than 0, and the intra-population inbreeding coefficient (Fis) for seven loci was positive. Three loci were moderately polymorphic (0.25 < polymorphism information content (PIC) <0.5), and five loci were highly polymorphic (PIC > 0.5); all eight loci had a moderate genetic differentiation level (0.05 < genetic differentiation coefficient (Fst) <0.25). As shown by the genetic diversity analysis, the He was bigger than the Ho for 10 populations, indicating the presence of a certain degree of intra-population inbreeding. The F had a negative value for four populations, suggesting that excessive random mating was present within each of them. Results of the analysis of molecular variance show that 19% of the total variation was attributed to among-individuals and 78% of the total variation originated from within-individuals. The adjusted Fst (F'st) was 0.073, indicative of a moderate level of genetic differentiation among the populations. The value of gene flow was greater than 1 (7.367), suggesting that genetic differentiation among populations was not caused by genetic drift. Results of the STRUCTURE analysis show that all the samples tested could be clustered into five ancestor groups. Results of the Unweighted Pair Group Method using Arithmetic Averages (UPGMA) clustering analyses show that the 84 plant samples could be divided into three clusters and natural populations from the 14 growing areas could be divided into two clusters. Clustering results of the populations were not affected by geographic distances, and gene flow occurred frequently among the populations, suggesting that the genetic variation among the natural populations of C. nitidissima var. phaeopubisperma from 14 growing areas was not influenced by environmental changes of these areas but mainly derived from the genetic variation present in pre-introduction populations.

Genetic Variation for Wild Populations of the Rare and Endangered Plant Glyptostrobus pensilis Based on Double-Digest Restriction Site-Associated DNA Sequencing.

Glyptostrobus pensilis is an endangered tree species, and detecting its genetic diversity can reveal the mechanisms of endangerment, providing references for the conservation of genetic resources. Samples of 137 trees across seven populations within Fujian Province were collected and sequenced using double-digest restriction site-associated DNA (ddRAD-seq). A total of 3,687,189 single-nucleotide polymorphisms (SNPs) were identified, and 15,158 high-quality SNPs were obtained after filtering. The genetic diversity in the populations was found to be low (Ho = 0.08630, He = 0.03475, π = 0.07239), with a high genetic differentiation coefficient (Fst). When K = 4, the coefficient of variation (CV) error value was minimized, suggesting that the 137 individuals could be divided into four groups, with frequent gene flow between them. Principal component analysis (PCA) divided the seven populations into two major categories based on their north-south geographic location. The clustering was consistent with those obtained from the PCA. The main reasons for the endangerment of G. pensilis are likely to be poor natural regeneration, human disturbances, and climatic factors. It is recommended that methods such as in situ conservation, ex situ conservation, and the establishment of germplasm banks be implemented to maintain the genetic diversity of G. pensilis populations.

Genetic diversity and structure of 15 full-sib families of Litopenaeus vannamei based on SSR markers

To clarify the genetic diversity and structure of the nucleus population of F1-generation Litopenaeus vannamei, this study utilized 15 pairs of highly polymorphic microsatellite primers to analyze the simple sequence repeat (SSR) markers and genetic diversity in 15 full-sib families of L. vannamei. A total of 112 alleles (Na) and 60.453 effective alleles (Ne) were identified among the selected 15 SSR loci, with the average polymorphic information content (PIC) of 0.648. The average Ne, observed heterozygosity (Ho), and expected heterozygosity (He) in the 15 F1 families varied from 1.925 to 2.626, 0.425 to 0.783, and 0.403 to 0.572, respectively. The 15 full-sib families were primarily clustered into three categories in the phylogenetic analysis, with the genetic distance between families ranging from 0.252 to 0.574. Additionally, the genetic differentiation coefficient (Fst) among the families varied from 0.112 to 0.278, indicating substantial genetic differentiation. Overall, this study suggested that the genetic diversity of the 15 full-sib families was moderate, providing valuable genetic insights for the subsequent breeding initiatives aimed at enhancing the tolerance of L. vannamei to high levels of soybean meal.

Genetic Diversity Analysis and Core Collection Construction of Ancient Sophora japonica L. Using SSR Markers.

Sophora japonica is an important native tree species in northern China, with high ornamental, medicinal, and ecological value. In order to elucidate the genetic resources of ancient S. japonica, 16 simple sequence repeat (SSR) markers were used to evaluate its genetic diversity and population structure and build a core collection of 416 germplasms from the Shandong, Shanxi, and Hebei provinces. A total of 160 alleles were detected, the mean major allele frequency (MAF)was 0.39, and the mean effective number of alleles (Ne) was 4.08. Shannon's information index (I), the observed heterozygosity (Ho), the expected heterozygosity (He), and the polymorphism information content (PIC) were 1.58, 0.64, 0.74, and 0.70, respectively, indicating relatively high genetic diversity in ancient S. japonica germplasms. Low genetic differentiation coefficient (Fst = 0.04) and frequent gene flow (Nm = 9.74) were found in the tested S. japonica populations, and an analysis of molecular variance (AMOVA) indicated that the genetic variation mainly came from within individuals (84%). A genetic structure and cluster analysis indicated that 416 ancient S. japonica germplasms could be divided into five subgroups, and there were obvious genetic exchanges among different subgroups. A core collection consisting of 104 (25% of the original collection) germplasms was constructed using the R language package Genetic Subsetter version 0.8 based on the stepwise regression method. The retention rates of the number of alleles (Na), Ne, I, He, and PIC were 87.50%, 106.24%, 103.02%, 102.50%, and 102.74%, respectively. The t-test analysis suggested that there were no significant differences between the core collection and the original collection. The principal coordinate analysis (PCoA) showed that the core collection was uniformly distributed within the initial collection and was able to fully represent the genetic diversity of the original collection. These results provide a scientific basis for the conservation and utilization of ancient S. japonica germplasms.

Assessing population genetic structure and diversity and their driving factors in Phoebe zhennan populations

BackgroundPhoebe zhennan, commonly known as “golden-thread nanmu,” is one of the most valuable and protected tree species in China. An accurate understanding of the population genetic structure and its environmental factors is of significance for the protection and selection of new P. zhennan varieties.ResultsSixteen nSSR and six cpSSR markers were used to determine the genetic diversity and population structure of P. zhennan and the effect of environmental factors on the genetic structure. The nSSR markers identified a total of 451 number of alleles (Na), while cpSSR markers detected 20 Na. A relative high level of genetic diversity was observed in the P. zhennan population evidenced by high Shannon’s information index (I) of 0.671 and 2.294 based on cpSSR and nSSR datasets. The low value of fixation index (F) observed from the nSSR dataset indicated low breeding within the population. The genetic differentiation was mainly detected within populations (only 28% and 13% of the variance being between populations according to the nSSR and cpSSR datasets). Among them, the HNSZX (H = 0.469) and SCSZZ (I = 1.943) populations exhibited the highest level of genetic diversity, while the HNXXT (H = 0.041) and SCLJS (I = 0.943) populations exhibited the lowest level of genetic diversity. The average genetic differentiation coefficient (Fst) and gene flow (Nm) were 0.022–0.128 and 1.698–11.373, respectively, which indicated a moderate level of genetic differentiation and a high level of gene flow. STRUCTURE, neighbor-joining clustering, and principal coordinate analysis divided 543 individuals into two or three categories based on the nSSR or cpSSR datasets. Four temperature, three precipitation, five chemical, five physical, and one soil texture variable showed significant effects on the genetic structure and distribution of P. zhennan populations. Compared to nSSR, the genetic differentiation among populations based on cpSSR datasets conformed to the geographic isolation model, suggesting that geographic and genetic distances should be considered for further genetic conservation and breeding utilization. The importance of in situ conservation units, such as populations with a high level of genetic diversity, more private alleles, and haplotypes (e.g., population SCGTS, SCYFS, and YNYJX), should be emphasized. Additionally, breeding, along with artificially assisted population regeneration and restoration, should also be carefully planned, taking into account climate and soil properties at the same time.ConclusionsIn conclusion, this study provided genetic background information for the genetic conservation, management, and utilization of P. zhennan.

Genetic Diversity of Native Provenance and Plantation Populations of Pinus sylvestris var. mongolica Based on SSR Markers and Morphological Traits.

Pinus sylvestris var. mongolica plays a crucial role in the ecological restoration and industrial raw material production of arid and semiarid regions in northern China. The widespread degradation of its near-mature plantation (over 30 years) is a significant concern, having been a topic of interest in recent decades. In this study, the genetic diversity and population genetic structure were assessed using 12 simple sequence repeat (SSR) markers within 11 native provenance populations and eight plantation populations. Additionally, variations in eight morphological traits of their offspring were evaluated at three sites in northern China. The results revealed high genetic diversity and weak genetic differentiation among the native provenance populations. The mean number of alleles (N a), allelic richness (A r), expected heterozygosity (H e), and Shannon-Wiener diversity index (I) were 5.492, 4.679, 0.550, and 1.120, respectively, and the genetic differentiation coefficient (F ST) was 0.022. Significant population effects of tree height and height to live crown base (HCB), as well as interactions of population with site and block within site, were observed in tree height, HCB, stem diameter at breast height (DBH), stem volume (VOL), crown shape (CS), and disease grade (DG). The genetic diversity parameters based on SSR markers and breeding values of tree height, DBH, HCB, VOL, and stem form (SF) of plantation populations were found to be lower than those of native provenance populations. Significant positive correlations were identified between the mean effective number of alleles per locus (N e) and VOL as well as H e and crown width (CW). Furthermore, the maximum temperature of the warmest month (BIO5) and the silt content (T_SILT) were identified as significant factors influencing genetic diversity parameters and morphological variation, respectively. The findings provide scientific support for the reduction of plantation degradation, the effective restoration, and the sustainable management of forests for this species.

Genetic Diversity and Population Structure Analysis of Pinus elliottii Germplasm Resources in Jiangxi Province.

This study aimed to compare and assess the genetic diversity and trends among the introduced family provenance, first-cycle superior trees breeding provenance, and improved-generation superior trees breeding provenance of Pinus elliottii using EST-SSR markers. The goal was to provide a foundation for advanced genetic improvement and sustainable utilization of P. elliottii in Jiangxi Province. A total of 417 individuals were analyzed for their genetic diversity and population structure using 19 pairs of SSR markers. The analysis identified 103 alleles across all the samples, with an average of 5.421 alleles per locus. Compared to other coniferous species, P. elliottii exhibited a moderate to high level of genetic diversity (I = 0.862, He = 0.457). Analysis of the molecular variance (AMOVA) revealed that 97.90% of the genetic variation occurred within provenances, consistent with a low genetic differentiation coefficient (Fst = 0.016 < 0.05) and high gene flow (Nm = 15.715) among provenances. In addition, analysis using STRUCTURE v. 2.3.4 software divided the 417 germplasm samples into two distinct groups, corroborating the results of the principal coordinates analysis (PCoA) and the unweighted pair group method with arithmetic (UPGMA) clustering analysis. Overall, the germplasm resources of P. elliottii exhibited rich genetic diversity, with the majority of the genetic variation occurring within provenances. For the genetic improvement of high-resin-yielding slash pines, breeding programs should prioritize populations with high genetic diversity while carefully selecting superior individuals from within those populations. These findings provide a solid foundation for breeding high-resin-yielding varieties and for future research on the sustainable utilization of these valuable resources.

Population genetic differentiation and structure of rare plant Anemone shikokiana based on genotyping-by-sequencing (GBS)

BackgroundAnemone shikokiana (Makino) Makino is a perennial herb of the genus Anemone in the family Ranunculaceae. Endemic to the Shandong Peninsula in China and Shikoku Island in Japan, it is a rare and endangered plant with a narrow, disjunct distribution. It is threatened with extinction and is in urgent need of conservation. Evaluating the genetic diversity of species, revealing the population genetic structure and gene flow, and inferring the population history are of great importance for species conservation, especially for rare and endangered plants.ResultsIn our study, 73 samples from eight wild populations in China were sequenced by Super-GBS, yielding a total of 40.59 G clean reads and 52,231 SNPs. Based on the obtained SNP data set, we evaluated the population genetic diversity, genetic structure, and gene flow of A. shikokiana. A low level of genetic diversity was found (He = 0.1925, Ho = 0.1422). The neighbor-joining (NJ) tree, principal component analysis and ADMIXTURE analysis suggested that these 73 A. shikokiana could be considered as two groups. Pairwise genetic differentiation coefficients (Fst) indicated that genetic differentiation was lower between adjacent populations and higher between geographically separated populations. The gene flow between Kunyu Mountain and Lao Mountain was very low. However, neither of the two regions showed evidence of Isolation by Distance.ConclusionsHere, we revealed the population genetic structure and gene flow of A. shikokiana from the Shandong Peninsula, China. This research provides valuable genetic resources for A. shikokiana and contributes to the scientific and effective conservation of the species.

Geographical variation and genetic diversity of Parashorea chinensis germplasm resources.

Parashorea chinensis is a rare monodominant species in southwest China known for its production of high-quality timber, is facing decline due to its narrow distribution, human interference and habitat destruction. However, there are no reports on genetic diversity and geographical variation of phenotypic traits of P. chinensis. In this study, phenotypic characters and genetic diversity of 15 germplasms resources from five provenances in southwest China were investigated, and their relationships with geographical and environmental factors was discussed. Our results revealed a rich phenotypic diversity among the germplasms, with variation coefficients ranging from 3.63% to 45.49%. Among the studied germplasms, NP03 from Napo and ML02 from Mengla region exhibited superior phenotypic traits. Notably, NP03 also demonstrated the highest genetic diversity. Genetic differentiation analyses including genetic differentiation coefficient (0.6264) and gene flow (0.3736) illustrated that genetic variation was most prevalent among populations. Furthermore, redundancy analysis showed that temperature related factors (maximum air temperature, annual mean temperature and minimum air temperature) significantly affected phenotypic variation. Similarly, altitude, longitude, latitude, annual mean precipitation and the minimum air temperature significantly impacted the level of genetic diversity. The molecular variation of the natural population of P. chinensis followed a certain geographical pattern. Our finding indicated abundant phenotypic variation among P. chinensis germplasms. However, populations exhibited low levels of genetic diversity alongside high genetic differentiation, potentially contributing to the species' rarity. Based on our results, NP03 and ML02 germplasm could be used as the parents for breeding superior germplasm of P. chinensis. Overall, this study provides valuable insights into germplasm diversity and conservation, genetic improvement, and utilization of P. chinensis.

Establishment and population genetic analysis of SNP fingerprinting of Chinese soft-shelled turtle (Pelodiscus sinensis)

Chinese soft-shelled turtle (Pelodiscus sinensis) is an important aquaculture species in China. However, with the continuous development of P. sinensis cultures, problems related to germplasm degradation and population mixing have become increasingly prominent. This has seriously affected the protection and utilization of germplasm resources by P. sinensis. To broaden the understanding of the germplasm resources of P. sinensis and improve the efficiency of germplasm identification, Super-GBS sequencing technology was used to conduct population genetic analysis of P. sinensis samples from six different populations distributed in five provinces. As a result, 1464,488 SNPs were identified. Genetic structure analysis revealed that the six P. sinensis populations could be divided into three sub-populations. The genetic differentiation coefficient of the DT and CY populations was very low (Fst=0.0088), indicating that differentiation had not yet occurred. Additionally, 15 KASP core markers for the identification of P. sinensis populations were developed using KASP typing technique for the first time. Genetic information can lay a foundation for the protection and utilization of germplasm resources by P. sinensis, and the fingerprinting database developed in this study provides a practical tool for authenticating P. sinensis.

Application effectiveness of "Youxin-1" in genetic diversity and structure analysis of local chickens.

China's local chicken breeds are rich in resources, and have formed different germplasm characteristics in the process of long-term selection and evolution. Scientific assessment of population genetic diversity and identification of inter-breed genetic structure are of great value to the protection and innovative utilization of local chicken breed resource. In order to evaluate the application effectiveness of 23K SNP chip "Youxin-1" in the analysis of genetic diversity and genetic structure of local chickens, we used RADseq to identify genomic genetic variation of 21 local chicken breeds and developed 23K chip "Youxin-1". The genetic statistics of each variety were calculated based on two sets of SNP data, and correlation, fitting and phylogenetic analysis were carried out to evaluate the application effectiveness of the chip. The results showed that the observed heterozygosity (Ho), polymorphism information content (PIC), inbred coefficient (FROH) and genetic differentiation coefficient (Fst) calculated based on the two SNP data sets were basically consistent in the 21 local chicken breeds. The genetic diversity of Langya chicken (LA), Piao chicken (PJ) and Wenchang chicken (WC) was relatively rich. The genetic diversity of Bian chickens (BJ), Langshan chickens (LS), Gushi chickens (GS), Dongxiang blue-eggshell chickens (DX) and Beijing fatty chickens (BY) was relatively poor, and the correlation coefficients of Ho, PIC, FROH and average Fst in the two groups were 0.794, 0.901, 0.926 and 0.984, respectively, all reaching extremely significant levels (P<0.01) with a high degree of fit (P<0.001) and R2 were 0.644, 0.827, 0.916 and 0.927. For the two sets of SNP data, the evolutionary tree constructed by neighbor-joining (NJ) method and maximum likelihood (ML) method was reasonable, and the 21 local chicken breeds were generally divided into six categories, which was consistent with the formation history and geographical distribution of the varieties. The 23K chip also realized reasonable clustering of the five new varieties without individual deviation. There are some differences in the estimation of genetic statistics using SNP with different densities, and data standardization is needed. 23K chip has good efficacy in the analysis of genetic diversity and structure of local chickens.

Genetic diversity and population structure of wild and artificially selected populations of the ridgetail white prawn (Exopalaemon carinicauda) using consolidated mitochondrial cytochrome b and microsatellite markers

The ridgetail white prawn (Exopalaemon carinicauda) belongs to the family Palaemonidae and genus Exopalaemon. Owing to its significant economic value and excellent nutritional properties, it is an important species for the development of saltwater aquaculture models in China. In this study, 160 individuals were collected from four wild populations and one artificially selected population using consolidated mitochondrial cytochrome b (mt-cyt b), and microsatellite molecular markers. The results showed that the hatcheries had lower genetic diversity than the wild samples, both at the levels of mt-cyt b (haplotype diversity: 0.123 VS 0.572; nucleotide diversity: 0.0003 VS 0.0014) and microsatellite (expected heterozygosity: 0.672 VS 0.752). Among the four wild populations, the Ningbo population sampled from the East China Sea showed higher genetic diversity in both mt-cyt b and microsatellites. A pairwise comparison of genetic differentiation coefficients revealed that the artificially selected population had not genetically diverged from the Cangzhou and Rizhao populations. However, the Ningbo population exhibited moderate to high genetic differentiation (compared to other populations), whereas the Zhanjiang population showed a high level of genetic differentiation, indicating a distinct geographical distribution pattern. Structural analysis revealed the presence of three lineage clusters in all current populations, and the artificially selected population predominantly consisted of lineage 3, accounting for 71.68 % of the population. Currently, the effective population size of hatcheries was <50, rendering them susceptible to the genetic threat of inbreeding depression. These findings provide a scientific basis for the conservation of wild germplasm resources of E. carinicauda and inform future breeding and management strategies for improved varieties.

Microsatellite analysis of genetic diversity and population differentiation of Acanthopagrus schlegelii in China

The study utilized 9 self-selected polymorphic microsatellite loci to amplify and investigate the genetic diversity and differentiation of Acanthopagrus schlegelii populations in 10 wild populations along the Chinese coast. The values of Polymorphic Information Content (PIC) ranged from 0.4433 to 0.5804, with an average value of 0.5143. The average number of alleles per locus (A) ranged from 3.0000 to 3.4444, with a mean value of 3.2333 and an overall value of 3.6667. The average number of effective alleles per locus (Ae) ranged from 2.0130 to 2.6014, with a mean value of 2.2994 and an overall value of 2.8013. The observed heterozygosity (Ho) ranged from 0.4607 to 0.5789, with an average value of 0.5278 and an overall value of 0.5261. The expected heterozygosity (He) ranged from 0.4657 to 0.5967, with an average value of 0.5183 and an overall value of 0.6224. The results of genetic differentiation showed the genetic differentiation coefficient (Fst) was 0.1806, and the gene flow (Nm) was 1.1342. The UPGMA cluster analysis indicated significant genetic differentiation among A. schlegelii populations along the Chinese coast, with the populations being divided into two groups, namely the northern and southern populations. The genetic differentiation structure of the southern population was inconsistent with its geographical distribution. This study utilized microsatellite molecular markers to investigate the genetic diversity and genetic differentiation of 10 wild A. schlegelii populations along the coast of China. The research results indicate that the genetic diversity of the 10 wild A. schlegelii populations is at a moderate level, with evidence of north-south differentiation. This provides a scientific basis for the conservation, germplasm improvement, and aquaculture of A. schlegelii resources in China. It also offers background information for recent stock enhancement and release projects and their impact on the genetic resources of A. schlegelii.

Genetic diversity and population structure of threeline grunt Parapristipoma trilineatum (Perciformes: Haemulidae) in China and Japan based on mtDNA control region

Parapristipoma trilineatum is an edible and economically important marine fish with high farming potential; however, this fish has not been widely investigated. To understand the germplasm resources of this marine fish, we investigated the range of P. trilineatum from Maizuru, Japan, to Hainan, China. Using the mitochondrial control region as a molecular marker, we analyzed the population structure, genetic diversity, and population history dynamics of P. trilineatum. The control region exhibited high haplotype diversity and nucleotide diversity of 0.996 and 0.016, respectively. The genetic differentiation coefficients indicated low differentiation between Japanese and other populations. Additionally, based on the results of SAMOVA, AMOVA, and genetic differentiation coefficients, P. trilineatum can be divided into two management units in fishery resources management: China and Japan. Populations with high genetic diversity are useful as genetic breeding materials. This study provides a basis for the selection and breeding of P. trilineatum.

The Phylogeography of Deciduous Tree Ulmus macrocarpa (Ulmaceae) in Northern China

Disentangling how climate oscillations and geographical events significantly influence plants’ genetic architecture and demographic history is a central topic in phytogeography. The deciduous ancient tree species Ulmus macrocarpa is primarily distributed throughout Northern China and has timber and horticultural value. In the current study, we studied the phylogenic architecture and demographical history of U. macrocarpa using chloroplast DNA with ecological niche modeling. The results indicated that the populations’ genetic differentiation coefficient (NST) value was significantly greater than the haplotype frequency (GST) (p &lt; 0.05), suggesting that U. macrocarpa had a clear phylogeographical structure. Phylogenetic inference showed that the putative chloroplast haplotypes could be divided into three groups, in which the group Ⅰ was considered to be ancestral. Despite significant genetic differentiation among these groups, gene flow was detected. The common ancestor of all haplotypes was inferred to originate in the middle–late Miocene, followed by the haplotype overwhelming diversification that occurred in the Quaternary. Combined with demography pattern and ecological niche modeling, we speculated that the surrounding areas of Shanxi and Inner Mongolia were potential refugia for U. macrocarpa during the glacial period in Northern China. Our results illuminated the demography pattern of U. macrocarpa and provided clues and references for further population genetics investigations of precious tree species distributed in Northern China.

Whole-genome resequencing revealed the population structure and selection signal of 4 indigenous Chinese laying ducks

The assessment of animal genetic structure had significant importance for the preservation and breeding of animal germplasm resources. Selection signals are genotype markers generated during the process of biological evolution, and the detection of selection signals could reveal the direction of species evolution. The aim of this study was to generate a whole-genome resequencing data from Jinding duck, Shanma duck, Youxian Partridge duck, and Taiwan Brown tsaiya duck to reveal their population structure and selection signals. The population structure analysis revealed significant genetic differences among the 4 indigenous laying ducks, indicating their independent lineage. Specifically, Shanma duck and Youxian partridge duck were closely and likely originated from a common ancestor. In addition, selection sweep analysis was performed using the population genetic differentiation coefficient (Fst) and nucleotide diversity ratio (π ratio). The top 5% was used as the threshold for the Fst and π ratio, and the 2 thresholds were combined to identify selected genomic regions. In the selected regions of the 3 comparison groups, 136, 143, and 268 candidate genes were detected. Further screening of all candidate genes revealed that 35 candidate genes appeared simultaneously in 3 comparative groups, with 16 genes annotated. The 16 genes were analyzed by Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses. The results revealed 5 functional genes (AQP3, PIK3C3, NOL6, RPP25, and DCTN3) that may be related to important economic traits in laying ducks and involved mainly invasopressin-regulated water reabsorption, ribosome biogenesis, and the PI3K signaling pathway. The results provide insights into the protection and exploitation of genetic resources of Chinese indigenous laying ducks.

Microsatellite marker-based analysis of the genetic diversity and population structure of three Arnebiae Radix in western China

Arnebiae Radix is an important medicinal and perennial herb found in Western China, particularly in the Xinjiang region. However, the assessment, utilization and conservation of Arnebiae Radix resources are still unexplored. In this study, we evaluated the genetic diversity of three Arnebiae Radix populations across 47 regions (Ae = 16, Ag = 16, Ad = 15) in Xinjiang, China, using inter-simple sequence repeat (ISSR) molecular markers. In total, 48 alleles were amplified by six pairs of primers screened with ISSR markers. The average number of effective alleles (Ne) was 1.5770. The percentage of interspecific genetic polymorphisms in A. guttata (Ag = 89.58 %) was greater than that in A. euchroma. and A. decumbens (Ae = Ad = 87.50 %). Intraspecific genetic polymorphisms, Bo Le (BL) population of A. euchroma exhibited the highest percentage of polymorphic bands (PPB% =58.33 %, Na = 1.313, Ne = 1.467, I = 0.0.366, H = 0.255), which indicated high genetic diversity. In contrast, the Tuo Li (TL) population of A. guttata had the lowest values for these parameters (PPB% =0.00 %, Na = 0.313, Ne = 1,000, I = 0.000, H = 0.000). The Arnebiae Radix germplasms were classified into two major groups (I and II) based on UPGMA cluster analysis (Fig. 8a) and principal coordinate analysis (PCOA). In addition, A. decumbens is placed in a separate category due to its high differentiation coefficient. The AMOVA and genetic differentiation coefficient results indicated that the genetic variation in Arnebiae Radix was predominantly due to intrapopulation differences (78 %). Additionally, the gene flow index (Nm) between populations was 2.4128, which further indicated that the genetic diversity of Arnebiae Radix was greater at the intrapopulation level. The destruction of the ecological environment leads to the continuous reduction and degradation of the genetic diversity of Arnebiae Radix germplasm resources. In this study, we used ISSR molecular markers to analyze the genetic diversity and relatedness of Arnebiae Radix, which revealed the genetic relationship of Arnebiae Radix germplasm resources at the molecular level and provided a scientific basis for future research on selecting and breeding good varieties, evaluating the quality of Arnebiae Radix, and conserving and utilizing its resources.

Genetic diversity of the common carp black strain population based on mtDNA (D-loop and cytb)

The common strain black carp (Cyprinus carpio var. baisenensis) is a culturally important carp strain that is raised and cultured in Guangxi Province, China. Its color reflects the interactions between the Burau people and their surrounding environment. The population of the common carp black strain was isolated and cultured in a rice-fish integration system. To explore the genetic diversity and protection of germplasm resources, we analyzed mitochondrial DNA (mtDNA) sequences, specifically the displacement loop (D-loop) and cytochrome b (Cytb), using single-nucleotide polymorphisms (SNP). We compared these sequences with those from four other local common carp populations. The study included a total of 136 adult common carps from five strain populations: the common black carp strain (HJ = 31), Jian (F = 30), Heilongjiang (H = 10), Songpu (S = 31), and Saijiang (SJ = 34). The results of the Cytb and D-loop analyses showed that the Heilongjiang carp (H) and Saijiang (SJ) populations had the highest levels of haplotype diversity (0.867 ± 0.034785) and nucleotide diversity (π = 0.0063 ± 0.000137 and 0.0093 ± 0.000411), respectively. On the other hand, the Common carp black strain population (HJ) exhibited the lowest haplotype diversity in both Cytb and D-loop, with haplotype 2 being the most commonly observed among the populations. Private haplotypes dominated the five common carp populations, which were significantly different at P<0.001. Furthermore, analyzing the coefficient of genetic differentiation (Fst), the highest genetic difference was observed between Saijiang (SJ) and Heilongjiang (H) (Fst = 0.963), whereas the lowest was observed between Songpu (S) and the Common carp black strain population (HJ) (Fst = 0.019) for the Cytb gene sequences. For the D-loop, the Common carp black strain population (HJ) and Songpu (S) (Fst = 0.7) had the highest values, and Heilongjiang (H) and Common black carp strain (HJ) had an Fst of 0.125. Additionally, the AMOVA analysis revealed a higher level of variance for the Cytb and D-loop genes, indicating lower genetic diversity within the local carp community. On the other hand, the phylogenetic tree analysis showed that the five carp populations were closely related and formed a distinct cluster. The distinct cluster of populations suggests a common ancestor or recent gene flow, possibly due to geographic proximity or migration history, and unique genetic characteristics, possibly due to adaptations or selective pressures. The results of this study provide valuable insights into the genetic diversity of the common strain black carp, which can have implications for conservation, breeding programs, evolutionary studies, and fisheries management.

Population Variation and Phylogeography of Cherry Blossom (Prunus conradinae) in China.

Prunus conradinae (subgenus Cerasus, Rosaceae) is a significant germplasm resource of wild cherry blossom in China. To ensure the comprehensiveness of this study, we used a large sample size (12 populations comprising 244 individuals) which involved the fresh leaves of P. conradinae in Eastern, Central, and Southwestern China. We combined morphological and molecular evidence (three chloroplast DNA (cpDNA) sequences and one nuclear DNA (nr DNA) sequence) to examine the population of P. conradinae variation and differentiation. Our results revealed that Central, East, and Southwest China are important regions for the conservation of P. conradinae to ensure adequate germplasm resources in the future. We also found support for a new variant, P. conradinae var. rubrum. We observed high genetic diversity within P. conradinae (haplotype diversity [Hd] = 0.830; ribotype diversity [Rd] = 0.798), with novel genetic variation and a distinct genealogical structure among populations. There was genetic variation among populations and phylogeographic structure among populations and three geographical groups (Central, East, and Southwest China). The genetic differentiation coefficient was the lowest in the Southwest region and the gene exchange was obvious, while the differentiation was obvious in Central China. In the three geographic groups, we identified two distinct lineages: an East China lineage (Central China and East China) and a Southwest China lineage ((Central China and Southwest China) and East China). These two lineages originated approximately 4.38 million years ago (Mya) in the early Pliocene due to geographic isolation. P. conradinae expanded from Central China to East China at 3.32 Mya (95% HPD: 1.12-5.17 Mya) in the Pliocene. The population of P. conradinae spread from East China to Southwest China, and the differentiation time was 2.17 Mya (95% (HPD: 0.47-4.54 Mya), suggesting that the population of P. conradinae differentiated first in Central and East China. The population of P. conradinae experienced differentiation from Central China to Southwest China around 1.10 Mya (95% HPD: 0.11-2.85 Mya) during the early Pleistocene of the Quaternary period. The southeastern region of East China, near Mount Wuyi, likely serves as a refuge for P. conradinae. This study establishes a theoretical foundation for the classification, identification, conservation, and exploitation of germplasm resources of P. conradinae.

Evidence for the Use of Karst Tiankengs as Shelters: The Effect of Karst Tiankengs on Genetic Diversity and Population Differentiation in Manglietia aromatica

Karst tiankengs in China are globally significant locations for studying ecological environments and plant diversity. However, there are few reports on how the unique geographical environment of tiankengs affects plant genetic diversity and genetic structure. This study used Hyper-seq gene sequencing technology to develop large-scale genomic SNPs of Manglietia aromatica, both within and outside the tiankengs. Its aim was to investigate the impact of tiankengs on the genetic diversity and genetic structure of the M. aromatica population. The analysis results indicate that the genetic diversity of the populations within the tiankeng (π = 0.2044) is higher than that of the populations outside of it (π = 0.1671), indicating that the tiankengs have a positive impact on species diversity. The genetic differentiation coefficient (FST) between the populations inside and outside the tiankeng was 0.0534 and the FST values of populations within the tiankeng were 0.077, 0.082, and 0.141, meaning that the genetic variation in the tiankengs is very high. The genetic similarity outside the tiankengs is also very high, indicating that the tiankengs are effectively preserving the genetic diversity of M. aromatica. Furthermore, the gene introgression analysis results gave no proof of gene flow between the three tiankeng populations. This suggests that the tiankengs not only protect species diversity, but also hinder gene flow between populations to some extent. However, this hindrance may gradually subside with the evolution of the tiankengs. The genetic structure analysis revealed that the M. aromatica population in Guangxi, China, can be classified into three subpopulations. The first is the tiankeng subpopulation, including all the populations in tiankengs. The second subpopulation consists of populations surrounding the tiankengs. These two subpopulations are distributed in Leye County in northwestern Guangxi, China, and are very close to each other. The third is the Huanjiang subpopulation, which is located far away from the tiankengs. Considering the direction of gene flow and genetic structure, it is speculated that the populations in the tiankengs evolved from the populations near the pit mouth. This study confirms that the tiankengs are shelters and provide a suitable habitat for the endangered plant M. aromatica, because its genetic diversity is well conserved and the species is well adapted to the habitat within the tiankengs.