Genetic Subdivision of Chemosynthetic Endosymbionts of Solemya velum along the Southern New England Coast

ABSTRACT Population-level genetic diversity in the obligate symbiosis between the bivalve Solemya velum and its thioautotrophic bacterial endosymbiont was examined. Distinct populations along the New England coast shared a single mitochondrial genotype but were fixed for unique symbiont genotypes, indicating high levels of symbiont genetic structuring and potential symbiont-host decoupling.

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Pollen-mediated gene flow ensures connectivity among spatially discrete sub-populations of Phalaenopsis pulcherrima, a tropical food-deceptive orchid

BMC Plant Biology ◽

10.1186/s12870-019-2179-y ◽

2019 ◽

Vol 19 (1) ◽

Cited By ~ 2

Author(s):

Zhe Zhang ◽

Stephan W. Gale ◽

Ji-Hong Li ◽

Gunter A. Fischer ◽

Ming-Xun Ren ◽

...

Keyword(s):

Genetic Diversity ◽

Gene Flow ◽

Polynomial Regression ◽

Genetic Erosion ◽

Population Level ◽

Hainan Island ◽

Paternity Analysis ◽

Genetic Structuring ◽

Long Distance ◽

High Genetic Diversity

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.

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Novel Microsatellite Markers Used for Determining Genetic Diversity and Tracing of Wild and Farmed Populations of the Amazonian Giant Fish Arapaima gigas

Genes ◽

10.3390/genes12091324 ◽

2021 ◽

Vol 12 (9) ◽

pp. 1324

Author(s):

Paola Fabiana Fazzi-Gomes ◽

Jonas da Paz Aguiar ◽

Diego Marques ◽

Gleyce Fonseca Cabral ◽

Fabiano Cordeiro Moreira ◽

...

Keyword(s):

Genetic Diversity ◽

Microsatellite Markers ◽

Amazon Basin ◽

Population Level ◽

Legal Aspects ◽

Genetic Management ◽

Genetic Structuring ◽

Environmental Pressures ◽

National Regulation ◽

Arapaima Gigas

The Amazonian symbol fish Arapaima gigas is the only living representative of the Arapamidae family. Environmental pressures and illegal fishing threaten the species’ survival. To protect wild populations, a national regulation must be developed for the management of A. gigas throughout the Amazon basin. Moreover, the reproductive genetic management and recruitment of additional founders by aquaculture farms are needed to mitigate the damage caused by domestication. To contribute to the sustainable development, we investigated the genetic diversity of wild and cultivated populations of A. gigas and developed a panel composed by 12 microsatellite markers for individual and population genetic tracing. We analyzed 368 samples from three wild and four farmed populations. The results revealed low rates of genetic diversity in all populations, loss of genetic diversity and high inbreeding rates in farmed populations, and genetic structuring among wild and farmed populations. Genetic tracing using the 12 microsatellite markers was effective, and presented a better performance in identifying samples at the population level. The 12-microsatellite panel is appliable to the legal aspects of the trade of the A. gigas, such as origin discrimination, reproductive genetic management by DNA profiling, and evaluation and monitoring of genetic diversity.

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SARS-CoV-2 attack rate and population immunity in southern New England, March 2020 - May 2021

10.1101/2021.12.06.21267375 ◽

2021 ◽

Author(s):

Thu Nguyen-Anh Tran ◽

Nathan B Wikle ◽

Fuhan Yang ◽

Haider Inam ◽

Scott Leighow ◽

...

Keyword(s):

New England ◽

Rhode Island ◽

Attack Rate ◽

Vaccine Coverage ◽

Population Level ◽

Emergency Setting ◽

Population Immunity ◽

Southern New England ◽

Disease Attack ◽

Vaccine Distribution

AbstractEstimating an infectious disease attack rate requires inference on the number of reported symptomatic cases of a disease, the number of unreported symptomatic cases, and the number of asymptomatic infections. Population-level immunity can then be estimated as the attack rate plus the number of vaccine recipients who had not been previously infected; this requires an estimate of the fraction of vaccines that were distributed to seropositive individuals. To estimate attack rates and population immunity in southern New England, we fit a validated dynamic epidemiological model to case, clinical, and death data streams reported by Rhode Island, Massachusetts, and Connecticut for the first 15 months of the COVID-19 pandemic, from March 1 2020 to May 31 2021. This period includes the initial spring 2020 wave, the major winter wave of 2020-2021, and the lagging wave of lineage B.1.1.7(Alpha) infections during March-April 2021. In autumn 2020, SARS-CoV-2 population immunity (equal to the attack rate at that point) in southern New England was still below 15%, setting the stage for a large winter wave. After the roll-out of vaccines in early 2021, population immunity in many states was expected to approach 70% by spring 2021, with more than half of this immune population coming from vaccinations. Our population immunity estimates for May 31 2021 are 73.4% (95% CrI: 72.9% - 74.1%) for Rhode Island, 64.1% (95% CrI: 64.0% - 64.4%) for Connecticut, and 66.3% (95% CrI: 65.9% - 66.9%) for Massachusetts, indicating that >33% of southern Englanders were still susceptible to infection when the Delta variant began spreading in July 2021. Despite high vaccine coverage in these states, population immunity in summer 2021 was lower than planned due to 34% (Rhode Island), 25% (Connecticut), and 28% (Massachusetts) of vaccine distribution going to seropositive individuals. Future emergency-setting vaccination planning will likely have to consider over-vaccination as a strategy to ensure that high levels of population immunity are reached during the course of an ongoing epidemic.

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Contrasting effects of local environment and grazing pressure on the genetic diversity and structure of Artemisia frigida

Conservation Genetics ◽

10.1007/s10592-021-01375-w ◽

2021 ◽

Author(s):

Khurelpurev Oyundelger ◽

Veit Herklotz ◽

Dörte Harpke ◽

Batlai Oyuntsetseg ◽

Karsten Wesche ◽

...

Keyword(s):

Genetic Diversity ◽

Isolation By Distance ◽

Grazing Intensity ◽

Population Level ◽

Local Environment ◽

Grazing Pressure ◽

Climatic Gradient ◽

Genetic Structuring ◽

Artemisia Frigida ◽

Genetic Diversity And Structure

AbstractDrylands count among the most globally extensive biomes, and while many desert and dry rangeland ecosystems are under threat, genetic structures of dryland species are still rarely studied. Artemisia frigida is one of the most widely distributed plant species in the temperate rangelands of Eurasia and North America, and it also dominates in many habitats of Mongolia due to its tolerance to low temperatures, drought and disturbance. Local environmental conditions and grazing pressure can influence species performance and affect spatial patterns of genetic diversity in contrasting ways, and our study set out to evaluate such effects on the genetic diversity and structure of A. frigida. We first developed new species-specific Simple Sequence Repeats (SSRs) markers using whole genome sequencing. We then analysed 11 populations of A. frigida that had been sampled along a large climatic gradient in Mongolia, which were sub-structured according to three levels of grazing intensity. Estimates of genetic diversity at the population level were high (HO = 0.56, HE = 0.73) and tended to increase with higher precipitation and soil nutrient availability. Grazing had no effect on genetic diversity, however, a high number of grazing-specific indicator alleles was found at grazed sites. Genetic differentiation among populations was extremely low (global GST = 0.034). Analysis of Molecular Variance revealed 5% variance between populations along the climatic gradient, with 3% of the variance being partitioned among different grazing intensity levels. We found no relationship between geographic and genetic distances, and thus no isolation by distance in this widely distributed species. The relatively low genetic structuring suggests that considerable gene flow exists among A. frigida populations across the rangelands of Mongolia, in spite of the pervasive grazing in the region.

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