scholarly journals Extensive genetic diversity among populations of the malaria mosquito Anopheles moucheti revealed by population genomics

2016 ◽  
Author(s):  
Caroline Fouet ◽  
Colince Kamdem ◽  
Stephanie Gamez ◽  
Bradley J. White

AbstractMalaria vectors are exposed to intense selective pressures due to large-scale intervention programs that are underway in most African countries. One of the current priorities is therefore to clearly assess the adaptive potential of Anopheline populations, which is critical to understand and anticipate the response mosquitoes can elicit against such adaptive challenges. The development of genomic resources that will empower robust examinations of evolutionary changes in all vectors including currently understudied species is an inevitable step toward this goal. Here we constructed double-digest Restriction Associated DNA (ddRAD) libraries and generated 6461 Single Nucleotide Polymorphisms (SNPs) that we used to explore the population structure and demographic history of wild-caught Anopheles moucheti from Cameroon. The genome-wide distribution of allelic frequencies among samples best fitted that of an old population at equilibrium, characterized by a weak genetic structure and extensive genetic diversity, presumably due to a large long term effective population size. Estimates of FST and Linkage Disequilibrium (LD) across SNPs reveal a very low genetic differentiation throughout the genome and the absence of segregating LD blocks among populations, suggesting an overall lack of local adaptation. Our study provides the first investigation of the genetic structure and diversity in An. moucheti at the genomic scale. We conclude that, despite a weak genetic structure, this species has the potential to challenge current vector control measures and other rapid anthropogenic and environmental changes thanks to its great genetic diversity.

Author(s):  
Yibo Hu ◽  
Dunwu Qi ◽  
Fuwen Wei

The red panda is listed on the 2016 IUCN red list as Endangered. It is now distributed only in China, Myanmar, India, Bhutan and Nepal. Human activities such as poaching and large-scale deforestation have caused serious declines in this forest-dwelling species. Although its ecological research has made much progress in the past decades, only recently witnessed the population genetic research advances of this species. This chapter reviews the advances in wild red panda conservation genetics from non-invasive genetics, genetic diversity, phylogeographic structure, population genetic structure, demographic history, subspecies differentiation, to its conservation and management. It presents detailed estimates of genetic diversity, assesses the role of paleo-climate changes, human activities and landscape features in shaping the genetic structure and demographic history of red pandas, and discusses the implications of conservation genetics findings for effective genetic monitoring and conservation management.


2017 ◽  
Vol 2017 ◽  
pp. 1-7 ◽  
Author(s):  
Surapon Yodsiri ◽  
Komgrit Wongpakam ◽  
Adisak Ardharn ◽  
Chadaporn Senakun ◽  
Sutthira Khumkratok

The Mekong River and its tributaries possess the second highest diversity in fish species in the world. However, the fish biodiversity in this river is threatened by several human activities, such as hydropower plant construction. Understanding the genetic diversity and genetic structure of the species is important for natural resource management. Belodontichthys truncatus Kottelat & Ng is endemic to the Mekong River basin and is an important food source for people in this area. In this study, the genetic diversity, genetic structure, and demographic history of the twisted-jaw fish, B. truncatus, were investigated using mitochondrial cytochrome b gene sequences. A total of 124 fish specimens were collected from 10 locations in the Mekong and its tributaries. Relatively high genetic diversity was found in populations of B. truncatus compared to other catfish species in the Mekong River. The genetic structure analysis revealed that a population from the Chi River in Thailand was genetically significantly different from other populations, which is possibly due to the effect of genetic drift. Demographic history analysis indicated that B. truncatus has undergone recent demographic expansion dating back to the end of the Pleistocene glaciation.


Forests ◽  
2021 ◽  
Vol 13 (1) ◽  
pp. 24
Author(s):  
Seung-Beom Chae ◽  
Hyo-In Lim ◽  
Yong-Yul Kim

The restoration of damaged or disrupted forests with genetically appropriate restoration planting material that can adapt to future environmental conditions will ensure the conservation of forest genetic resources. Abies koreana is endemic to the Republic of Korea, with declining populations under current environmental changes. In this study, we examined the genetic diversity of its largest population growing on Mt. Hallasan to determine the sampling size of planting material from the population that will ensure 95% coverage of alleles in the population. We evaluated the genetic diversity and spatial genetic structure of three subpopulations of A. koreana on Mt. Hallasan. A total of 456 samples were evaluated using 10 microsatellites. The observed heterozygosity and expected heterozygosity were 0.538 and 0.614 at the population level, respectively. The differences among the subpopulations accounted for 4% of the total variance. Intervals between individuals of the sample to be extracted were based on the two-target distance (5 and 10 m) inferred from the spatial genetic structure. Through random sampling methods considering the target distance, we showed that genetic diversity can be captured by obtaining at least 35 individuals in the population of A. koreana on Mt. Hallasan.


2021 ◽  
Author(s):  
◽  
Alexander Halliwell

<p>Nemadactylus macropterus, commonly known as tarakihi in New Zealand is highly regarded by commercial and recreational fishers and considered a taonga by iwi and customary fisheries. For many years N. macropterus was New Zealand’s second most important commercial catch and is currently the third most valuable inshore commercial finfish fishery in which 90% is consumed by the domestic market. However, despite the apparent importance, relatively little is known about the population structure of the N. macropterus. In 2017 the first fully quantitative stock assessment was conducted on the east coast N. macropterus fisheries as one stock. Alarmingly, the east coast fishery was estimated to be 15.9% of the unexploited spawning biomass and predicted to have been declining for the past thirty years. In an effort to rebuild the fishery, several rebuild plans have been purposed and commercial catch limits have been reduced. In order to rebuild and successfully manage a viable future N. macropterus fishery, an understanding of demographic connectivity and genetic connectivity among N. macropterus populations is essential.  The overall goal of this thesis research was to investigate the population genetic structure, genetic diversity and demographic history of N. macropterus using fish sampled from around New Zealand. This was achieved by analysing hyper variable region one of mitochondrial DNA for 370 N. macropterus collected from 14 locations. No genetic differentiation was observed among the 14 locations, an indication that N. macropterus have a panmictic genetic structure. Furthermore, N. macropterus display a relatively high level of genetic diversity and appear to have a large stable population with a long evolutionary history. The Bayesian skyline analysis indicates the N. macropterus historic population has gone through two expansions. The mostly likely cause of this is an expansion before and after the last glacial maximum.  The genetic diversity and demographic history of N. sp was also studied using samples collected from around the Three Kings Islands of New Zealand. The complete mitochondrial genome of N. macropterus was reconstructed from bulk DNA sequencing data and a set of specific mtDNA primers were developed to amplify hyper variable region one. The DNA sequencing data provided by these primers with the addition of published control region sequences was used to reconstruct the Nemadactylus phylogeny.</p>


2021 ◽  
Vol 12 ◽  
Author(s):  
Shumiao Zhang ◽  
Chao Li ◽  
Yiping Li ◽  
Qi Chen ◽  
Defu Hu ◽  
...  

The reintroduction is an important conservation tool to restore a species in its historically distribution area, but the rate of reintroduction success varies across species or regions due to different reasons. Genetic evaluation is important to the conservation management of reintroduced species. Conservation concerns relate to genetic threats for species with a small population size or severely historically bottle-necked species, such as negative consequences associated with loss of genetic diversity and inbreeding. The last 40years have seen a rapid increasing of population size for Père David’s deer (Elaphurus davidianus), which originated from a limited founder population. However, the genetic structure of reintroduced Père David’s deer has not been investigated in terms of population genomics, and it is still not clear about the evolutionary history of Père David’s deer and to what extent the inbreeding level is. Conservation genomics methods were used to reconstruct the demographic history of Père David’s deer, evaluate genetic diversity, and characterize genetic structure among 18 individuals from the captive, free-ranging and wild populations. The results showed that 1,456,457 single nucleotide polymorphisms (SNPs) were obtained for Père David’s deer, and low levels of genome-wide genetic diversity were observed in Père David’s deer compared with Red deer (Cervus elaphus) and Sika deer (Cervus nippon). A moderate population genetic differentiation was detected among three populations of Père David’s deer, especially between the captive population in Beijing Père David’s deer park and the free-ranging population in Jiangsu Dafeng National Nature Reserve. The effective population size of Père David’s deer started to decline ~25.8ka, and the similar levels of three populations’ LD reflected the genetic impacts of long-term population bottlenecks in the Père David’s deer. The findings of this study could highlight the necessity of individual exchange between different facilities, and genetic management should generally be integrated into conservation planning with other management considerations.


2020 ◽  
Author(s):  
HaiXia Zhan ◽  
ZhongPing Hao ◽  
Rui Tang ◽  
LiNi Zhu ◽  
JingJiang Zhou ◽  
...  

Abstract Background: Strongyllodes variegatus (Fairmaire) is a major insect pest of oilseed rape in China. Despite its economic importance, the contribution of its population genetics in the development of any suitable protection control strategy for the management of oilseed rape crops is poorly studied. It is a much urgent need to prevent its spread to the rest of the world. Results: Using the sequences of mitochondrial DNA cytochrome c oxidase subunit I (COI) and cytochrome b (Cytb) as genetic markers, we analyzed the population genetic diversity and structure of 437 individuals collected from 15 S. variegates populations located in different oilseed rape production areas in China. In addition, we estimated the demographic history using neutrality test and mismatch distribution analysis. The high level of genetic diversity was detected among the COI and Cytb sequences of S. variegates. The population structure analyses strongly suggested three distinct genetic and geographical regions in China with limited gene flow. The Mantel test showed that the genetic distance was greatly influenced by the geographical distance. The demographic analyses showed that S. variegates had experienced population fluctuation during the Pleistocene Epoch, which was likely to be related to the climatic changes.Conclusion: Overall, these results demonstrate that the strong genetic structure of S. variegates populations in China, which is attributed by the isolation through the geographical distance among populations, their weak flight capacity and subsequent adaptation to the regional ecological conditions.


2019 ◽  
Author(s):  
Guia Giovannelli ◽  
Caroline Scotti-Saintagne ◽  
Ivan Scotti ◽  
Anne Roig ◽  
Ilaria Spanu ◽  
...  

AbstractFragmentation acting over geological times confers wide, biogeographical scale, genetic diversity patterns to species, through demographic and natural selection processes. To test the effects of historical fragmentation on the genetic diversity and differentiation of a major European forest tree and to resolve its demographic history, we describe and model its spatial genetic structure and gene genealogy. We then test which Pleistocene event, whether recent or ancient, could explain its widespread but patchy geographic distribution using population genetic data, environmental data and realistic demographic timed scenarios.The taxon of interest is a conifer forest tree, Pinus nigra (Arnold), the European black pine, whose populations are located in the mountains of southern Europe and North Africa, most frequently at mid-elevation. We used a set of different genetic markers, both neutral and potentially adaptive, and either bi-parentally or paternally inherited, and we sampled natural populations across the entire range of the species. We analysed the data using frequentist population genetic methods as well as Bayesian inference methods to calibrate realistic, demographic timed scenarios.Species with geographically fragmented distribution areas are expected to display strong among-population genetic differentiation and low within-population genetic diversity. Contrary to these expectations, we show that the current diversity of Pinus nigra and its weak genetic spatial structure are best explained as resulting from late Pleistocene or early Holocene fragmentation of one ancestral population into seven genetic lineages, which we found to be the main biogeographical contributors of the natural black pine forests of today. Gene flow among the different lineages is strong across forests and many current populations are admixed between lineages. We propose to modify the currently accepted international nomenclature made of five subspecies and name these seven lineages using regionally accepted subspecies-level names.HighlightsThe European black pine, Pinus nigra (Arnold), has a weak spatial genetic structure.Gene flow among populations is frequent and populations are often of admixed origin.Current genealogies result from recent, late Pleistocene or Holocene events.Seven modern genetic lineages emerged from divergence and demographic contractions.These seven lineages warrant a revision of subspecies taxonomic nomenclature.


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