scholarly journals Microsatellites reveal that genetic mixing commonly occurs between invasive fall armyworm populations in Africa

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Amy J. Withers ◽  
Jolanda de Boer ◽  
Gilson Chipabika ◽  
Lei Zhang ◽  
Judith A. Smith ◽  
...  

AbstractUnderstanding the population structure and movements of the invasive fall armyworm (FAW, Spodoptera frugiperda) is important as it can help mitigate crop damage, and highlight areas at risk of outbreaks or evolving insecticide resistance. Determining population structure in invasive FAW has been a challenge due to genetic mutations affecting the markers traditionally used for strain and haplotype identification; mitochondrial cytochrome oxidase I (COIB) and the Z-chromosome-linked Triosephosphate isomerase (Tpi). Here, we compare the results from COIB and Tpi markers with highly variable repeat regions (microsatellites) to improve our understanding of FAW population structure in Africa. There was very limited genetic diversity using the COIB marker, whereas using the TpiI4 marker there was greater diversity that showed very little evidence of genetic structuring between FAW populations across Africa. There was greater genetic diversity identified using microsatellites, and this revealed a largely panmictic population of FAW alongside some evidence of genetic structuring between countries. It is hypothesised here that FAW are using long-distance flight and prevailing winds to frequently move throughout Africa leading to population mixing. These approaches combined provide important evidence that genetic mixing between invasive FAW populations may be more common than previously reported.

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Agnieszka Sutkowska ◽  
Józef Mitka ◽  
Tomasz Warzecha ◽  
Jakub Bunk ◽  
Julia Rutkowska ◽  
...  

AbstractThe genetic diversity in 11 populations of Gladiolus imbricatus in five mountain ranges, including the Tatra, Pieniny, Gorce, Beskid Niski (Western Carpathians) and Bieszczady Mts (Eastern Carpathians), was studied with inter-simple sequence repeat (ISSR) markers. The species is a perennial plant occurring in open and semi-open sites of anthropogenic origin (meadows and forest margins). We checked a hypothesis on the microrefugial character of the plant populations in the Pieniny Mts, a small calcareous Carpathian range of complicated relief that has never been glaciated. Plant populations in the Tatra and Pieniny Mts had the highest genetic diversity indices, pointing to their long-term persistence. The refugial vs. the non-refugial mountain ranges accounted for a relatively high value of total genetic variation [analysis of molecular variance (AMOVA), 14.12%, p = 0.003]. One of the Pieniny populations was of hybridogenous origin and shared genetic stock with the Tatra population, indicating there is a local genetic melting pot. A weak genetic structuring of populations among particular regions was found (AMOVA, 4.5%, p > 0.05). This could be an effect of the frequent short-distance and sporadic long-distance gene flow. The dispersal of diaspores between the remote populations in the Western Carpathians and Eastern Carpathians could be affected by the historical transportation of flocks of sheep from the Tatra to Bieszczady Mts.


Animals ◽  
2020 ◽  
Vol 10 (8) ◽  
pp. 1309
Author(s):  
Veronika Kharzinova ◽  
Arsen Dotsev ◽  
Anastasiya Solovieva ◽  
Olga Sergeeva ◽  
Georgiy Bryzgalov ◽  
...  

To examine the genetic diversity and population structure of domestic reindeer, using the BovineHD BeadChip, we genotyped reindeer individuals belonging to the Nenets breed of the five main breeding regions, the Even breed of the Republic of Sakha, the Evenk breed of the Krasnoyarsk and Yakutia regions, and the Chukotka breed of the Chukotka region and its within-breed ecotype, namely, the Chukotka–Khargin, which is bred in Yakutia. The Chukotka reindeer was shown to have the lowest genetic diversity in terms of the allelic richness and heterozygosity indicators. The principal component analysis (PCA) results are consistent with the neighbor-net tree topology, dividing the reindeer into groups according to their habitat location and origin of the breed. Admixture analysis indicated a genetic structuring of two groups of Chukotka origin, the Even breed and most of the geographical groups of the Nenets breed, with the exception of the Murmansk reindeer, the gene pool of which was comprised of the Nenets and apparently the native Sami reindeer. The presence of a genetic component of the Nenets breed in some reindeer inhabiting the Krasnoyarsk region was detected. Our results provide a deeper insight into the current intra-breeding reindeer genetic diversity, which is an important requirement for future reindeer herding strategies and for animal adaptation to environmental changes.


2020 ◽  
Author(s):  
Yibing Zeng ◽  
Tao Xiong ◽  
Bei Liu ◽  
Elma Carstens ◽  
Xiangling Chen ◽  
...  

Phyllosticta citriasiana is the causal agent of citrus tan spot, an important pomelo disease in Asia. At present, there is little or no information on the epidemiology or population structure of P. citriasiana. Using simple sequence repeat (SSR) markers, 94 isolates obtained from three pomelo production regions in southern/southeastern China were analyzed. The analyses showed high genetic diversity in each of the three geographic populations. A STRUCTURE analysis revealed two genetic clusters among the 94 isolates, one geographic population was dominated by genotypes in one cluster while the other two geographic populations were dominated by genotypes of the second cluster. P. citriasiana has a heterothallic mating system with two idiomorphs, MAT1-1 and MAT1-2. Analyses using mating type-specific primers revealed that both mating types were present in all three geographic populations, and in all three populations the mating type ratios were in equilibrium. Although the sexual stage of the fungus has not been discovered yet, analyses of allelic associations indicated evidence for sexual and asexual reproduction within and among populations. Despite the observed genetic differentiation among the three geographic populations, evidence for long-distance gene flow was found.


2019 ◽  
Vol 19 (1) ◽  
Author(s):  
Zhe Zhang ◽  
Stephan W. Gale ◽  
Ji-Hong Li ◽  
Gunter A. Fischer ◽  
Ming-Xun Ren ◽  
...  

Abstract Background Gene flow in plants via pollen and seeds is asymmetrical at different geographic scales. Orchid seeds are adapted to long-distance wind dispersal but pollinium transfer is often influenced by pollinator behavior. We combined field studies with an analysis of genetic diversity among 155 physically mapped adults and 1105 F1 seedlings to evaluate the relative contribution of pollen and seed dispersal to overall gene flow among three sub-populations of the food-deceptive orchid Phalaenopsis pulcherrima on Hainan Island, China. Results Phalaenopsis pulcherrima is self-sterile and predominantly outcrossing, resulting in high population-level genetic diversity, but plants are clumped and exhibit fine-scale genetic structuring. Even so, we detected low differentiation among sub-populations, with polynomial regression analysis suggesting gene flow via seed to be more restricted than that via pollen. Paternity analysis confirmed capsules of P. pulcherrima to each be sired by a single pollen donor, probably in part facilitated by post-pollination stigma obfuscation, with a mean pollen flow distance of 272.7 m. Despite limited sampling, we detected no loss of genetic diversity from one generation to the next. Conclusions Outcrossing mediated by deceptive pollination and self-sterility promote high genetic diversity in P. pulcherrima. Long-range pollinia transfer ensures connectivity among sub-populations, offsetting the risk of genetic erosion at local scales.


2017 ◽  
Vol 16 (2) ◽  
pp. 156-168 ◽  
Author(s):  
S. Geethanjali ◽  
J. Anitha Rukmani ◽  
D. Rajakumar ◽  
P. Kadirvel ◽  
P.L. Viswanathan

AbstractA world-wide coconut germplasm collection (79 genotypes) was analyzed for genetic diversity and population structure based on 48 simple sequence repeat (SSR) loci. The genotypes displayed moderately high amount of genetic diversity, which was strongly structured according to geographical origins. Number of SSR alleles ranged from 2 to 7 with an average of 4.1 per locus. Gene diversity (expected heterozygosity) estimates ranged from 0.162 to 0.811 with a mean of 0.573. Polymorphism information content values ranged from 0.149 to 0.785 with an average of 0.522. Hierarchical clustering analysis grouped the genotypes into two major clusters with two sub-groups in each, which corresponded with the geographic origins. The first cluster comprised of ‘Tall’ genotypes originated from Indo-Atlantic and South Asia regions. The second cluster comprised mostly of ‘Dwarf’ genotypes and some Tall genotypes which originated from Indo-Pacific and South-East Asia regions. Model-based clustering by STRUCTURE analysis also supported the presence of clear genetic structuring in the collection with two major populations (K = 2) and four sub-populations (K = 4). The proportion of SSR locus-pairs in linkage disequilibrium was low (2.4%). Association analysis in a subset of 44 genotypes detected a single SSR locus, CnCir73 (chromosome 1) putatively associated with fruit yield component traits, which corresponded with a previously mapped quantitative trait locus in coconut.


Author(s):  
Johanna Honka ◽  
Serena Baini ◽  
Jeremy Searle ◽  
Laura Kvist ◽  
Jouni Aspi

The population numbers of taiga bean goose (Anser fabalis fabalis) have halved during recent decades. Since this subspecies is hunted throughout most of its range, the decline is of management concern. Knowledge of the genetic population structure and diversity is important for guiding management and conservation efforts. Genetically unique subpopulations might be hunted to extinction if not managed separately, and any inbreeding depression or lack of genetic diversity may affect the ability to adapt to changing environments and increase the extinction risk. We used microsatellite and mitochondrial DNA markers to study the genetic population structure and diversity among taiga bean geese breeding within the Central flyway management unit using non-invasively collected feathers. We found some genetic structuring with the maternally inherited mitochondrial DNA between four geographic regions (ɸ = 0.11-0.20) but none with the nuclear microsatellite markers (all pairwise F-values 0.002- 0.005). These results could be explained by female natal philopatry and male-biased dispersal, which completely homogenizes the nuclear genome. Therefore, the population could be managed as a single unit. Genetic diversity was still at a moderate level (average H = 0.69) and there were no signs of past population size reductions, although significantly positive inbreeding coefficients in all sampling sites (F = 0.05-0.10) and high relatedness values (r = 0.60-0.86) between some individuals could indicate inbreeding. In addition, there was evidence of either incomplete lineage sorting or introgression from the pink-footed goose (A. brachyrhynchus). The current population is not under threat by genetic impoverishment but monitoring in the future is desirable.


PLoS ONE ◽  
2020 ◽  
Vol 15 (11) ◽  
pp. e0241452
Author(s):  
Chen Wang ◽  
Xiang Ma ◽  
Mingxun Ren ◽  
Liang Tang

Hopea hainanensis Merrill & Chun (Dipterocarpaceae) is an endangered tree species restricted to Hainan Island, China and a small part of Northern Vietnam. On Hainan Island, it is an important indicator species for tropical forests. However, because of its highly valued timber, H. hainanensis has suffered from overexploitation, leading to a sharp population decline. To facilitate the conservation of this species, genetic diversity and population structure were assessed using 12 SSR markers for 10 populations sampled across Hainan Island. Compared to non-threatened Hopea species, H. hainanensis exhibited reduced overall genetic diversity and increased population differentiation (AMOVA: FST = 0.23). Bayesian model-based clustering and principal coordinate analysis consistently assigned H. hainanensis individuals into three genetic groups, which were found to be widespread and overlapping geographically. A Mantel test found no correlation between genetic and geographical distances (r = 0.040, p = 0.418). The observed genetic structure suggests that long-distance gene flow occurred among H. hainanensis populations prior to habitat fragmentation. A recent population bottleneck was revealed, which may cause rapid loss of genetic diversity and increased differentiation across populations. Based on these findings, appropriate strategies for the long-term conservation of the endangered species H. hainanensis are proposed.


ZooKeys ◽  
2020 ◽  
Vol 911 ◽  
pp. 139-160 ◽  
Author(s):  
Shyama Sundari Devi Chanthran ◽  
Phaik-Eem Lim ◽  
Yuan Li ◽  
Te-Yu Liao ◽  
Sze-Wan Poong ◽  
...  

A background study is important for the conservation and stock management of a species. Terapon jarbua is a coastal Indo-Pacific species, sourced for human consumption. This study examined 134 samples from the central west and east coasts of Peninsular (West) Malaysia and East Malaysia. A 1446-bp concatenated dataset of mtDNA COI and Cyt b sequences was used in this study and 83 haplotypes were identified, of which 79 are unique haplotypes and four are shared haplotypes. Populations of T. jarbua in Malaysia are genetically heterogenous as shown by the high level of haplotype diversity ranging from 0.9167–0.9952, low nucleotide diversity ranging from 0.0288–0.3434, and high FST values (within population genetic variation). Population genetic structuring is not distinct as shown by the shared haplotypes between geographic populations and mixtures of haplotypes from different populations within the same genetic cluster. The gene flow patterns and population structuring observed among these regions are likely attributed to geographical distance, past historical events, allopatric speciation, dispersal ability and water currents. For instance, the mixture of haplotypes revealed an extraordinary migration ability of T. jarbua (>1200 km) via ancient river connectivity. The negative overall value of the neutrality test and a non-significant mismatch distribution are consistent with demographic expansion(s) in the past. The median-joining network concurred with the maximum likelihood haplotype tree with three major clades resolved. The scarcity of information on this species is an obstacle for future management and conservation purposes. Hence, this study aims to contribute information on the population structure, genetic diversity, and historical demography of T. jarbua in Malaysia.


2020 ◽  
Vol 21 (5) ◽  
pp. 927-939
Author(s):  
M. Crotti ◽  
C. E. Adams ◽  
E. C. Etheridge ◽  
C. W. Bean ◽  
A. R. D. Gowans ◽  
...  

Abstract The European whitefish Coregonus lavaretus complex represents one of the most diverse radiations within salmonids, with extreme morphological and genetic differentiation across its range. Such variation has led to the assignment of many populations to separate species. In Great Britain, the seven native populations of C. lavaretus (two in Scotland, four in England, one in Wales) were previously classified into three species, and recent taxonomic revision resurrected the previous nomenclature. Here we used a dataset of 15 microsatellites to: (1) investigate the genetic diversity of British populations, (2) assess the level of population structure and the relationships between British populations. Genetic diversity was highest in Welsh (HO = 0.50, AR = 5.29), intermediate in English (HO = 0.41–0.50, AR = 2.83–3.88), and lowest in Scottish populations (HO = 0.28–0.35, AR = 2.56–3.04). Population structure analyses indicated high genetic differentiation (global FST = 0.388) between all populations but for the two Scottish populations (FST = 0.063) and two English populations (FST = 0.038). Principal component analysis and molecular ANOVA revealed separation between Scottish, English, and Welsh populations, with the Scottish populations being the most diverged. We argue that the data presented here are not sufficient to support a separation of the British European whitefish populations into three separate species, but support the delineation of different ESUs for these populations.


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