scholarly journals The genetic structure of the European black pine (Pinus nigra Arnold) is shaped by its recent Holocene demographic history

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.

Heredity ◽  
2020 ◽  
Vol 126 (1) ◽  
pp. 63-76
Author(s):  
Sarah M. Griffiths ◽  
Mark J. Butler ◽  
Donald C. Behringer ◽  
Thierry Pérez ◽  
Richard F. Preziosi

AbstractUnderstanding population genetic structure can help us to infer dispersal patterns, predict population resilience and design effective management strategies. For sessile species with limited dispersal, this is especially pertinent because genetic diversity and connectivity are key aspects of their resilience to environmental stressors. Here, we describe the population structure of Ircinia campana, a common Caribbean sponge subject to mass mortalities and disease. Microsatellites were used to genotype 440 individuals from 19 sites throughout the Greater Caribbean. We found strong genetic structure across the region, and significant isolation by distance across the Lesser Antilles, highlighting the influence of limited larval dispersal. We also observed spatial genetic structure patterns congruent with oceanography. This includes evidence of connectivity between sponges in the Florida Keys and the southeast coast of the United States (>700 km away) where the oceanographic environment is dominated by the strong Florida Current. Conversely, the population in southern Belize was strongly differentiated from all other sites, consistent with the presence of dispersal-limiting oceanographic features, including the Gulf of Honduras gyre. At smaller spatial scales (<100 km), sites showed heterogeneous patterns of low-level but significant genetic differentiation (chaotic genetic patchiness), indicative of temporal variability in recruitment or local selective pressures. Genetic diversity was similar across sites, but there was evidence of a genetic bottleneck at one site in Florida where past mass mortalities have occurred. These findings underscore the relationship between regional oceanography and weak larval dispersal in explaining population genetic patterns, and could inform conservation management of the species.


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.


PeerJ ◽  
2019 ◽  
Vol 7 ◽  
pp. e7953 ◽  
Author(s):  
Su-Fang Niu ◽  
Ren-Xie Wu ◽  
Yun Zhai ◽  
Hao-Ran Zhang ◽  
Zhong-Lu Li ◽  
...  

Late Pleistocene climate oscillations are believed to have greatly influenced the distribution, population dynamics, and genetic variation of many marine organisms in the western Pacific. However, the impact of the late Pleistocene climate cycles on the demographic history and population genetics of pelagic fish in the northern South China Sea (SCS) remains largely unexplored. In this study, we explored the demographic history, genetic structure, and genetic diversity of Decapterus maruadsi, a typical pelagic fish, over most of its range in the northern SCS. A 828–832 bp fragment of mitochondrial control region were sequenced in 241 individuals from 11 locations. High haplotype diversity (0.905–0.980) and low nucleotide diversity (0.00269–0.00849) was detected, revealing low levels of genetic diversity. Demographic history analysis revealed a pattern of decline and subsequent rapid growth in the effective population size during deglaciation, which showed that D. maruadsi experienced recent demographic expansion after a period of low effective population size. Genetic diversity, genetic structure, and phylogenetic relationship analysis all demonstrated that no significant genetic differentiation existed among the populations, indicating that D. maruadsi was panmictic throughout the northern SCS. Periodic sea-level changes, fluctuation of the East Asian Monsoon, and Kuroshio variability were responsible for the population decline and expansion of D. maruadsi. The demographic history was the primary reason for the low levels of genetic diversity and the lack of significant genetic structure. The life history characteristics and ocean currents also had a strong correlation with the genetic homogeneity of D. maruadsi. However, the genetic structure of the population (genetic homogeneity) is inconsistent with biological characteristics (significant difference), which is an important reminder to identify and manage the D. maruadsi population carefully.


2014 ◽  
Vol 57 (2) ◽  
pp. 1 ◽  
Author(s):  
Giullia Forti ◽  
Evandro Vagner Tambarussi ◽  
Paulo Yoshio Kageyama ◽  
Maria Andreia Moreno ◽  
Elza Martins Ferraz ◽  
...  

2014 ◽  
Vol 12 (2) ◽  
pp. 129-133 ◽  
Author(s):  
Arthur Tavares de Oliveira Melo ◽  
Alexandre Siqueira Guedes Coelho ◽  
Marlei Ferreira Pereira ◽  
Angel José Vieira Blanco ◽  
Edivani Villaron Franceschinelli

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Qiong Fu ◽  
Jie Deng ◽  
Min Chen ◽  
Yan Zhong ◽  
Guo-Hui Lu ◽  
...  

Abstract Background Rivers and streams facilitate movement of individuals and their genes across the landscape and are generally recognized as dispersal corridors for riparian plants. Nevertheless, some authors have reported directly contrasting results, which may be attributed to a complex mixture of factors, such as the mating system and dispersal mechanisms of propagules (seed and pollen), that make it difficult to predict the genetic diversity and population structure of riparian species. Here, we investigated a riparian self-fertilizing herb Caulokaempferia coenobialis, which does not use anemochory or zoochory for seed dispersal; such studies could contribute to an improved understanding of the effect of rivers or streams on population genetic diversity and structure in riparian plants. Using polymorphic ISSR and cpDNA loci, we studied the effect at a microgeographic scale of different stream systems (a linear stream, a dendritic stream, and complex transverse hydrological system) in subtropical monsoon forest on the genetic structure and connectivity of C. coenobialis populations across Dinghu Mountain (DH) and Nankun Mountain (NK). Results The results indicate that the most recent haplotypes (DH: H7, H8; NK: h6, h7, h11, h12) are not shared among local populations of C. coenobialis within each stream system. Furthermore, downstream local populations do not accumulate genetic diversity, whether in the linear streamside local populations across DH (H: 0.091 vs 0.136) or the dendritic streamside local populations across NK (H: 0.079 vs 0.112, 0.110). Our results show that the connectivity of local C. coenobialis populations across DH and NK can be attributed to historical gene flows, resulting in a lack of spatial genetic structure, despite self-fertilization. Selfing C. coenobialis can maintain high genetic diversity (H = 0.251; I = 0.382) through genetic differentiation (GST = 0.5915; FST = 0.663), which is intensified by local adaptation and neutral mutation and/or genetic drift in local populations at a microgeographic scale. Conclusion We suggest that streams are not acting as corridors for dispersal of C. coenobialis, and conservation strategies for maintaining genetic diversity of selfing species should be focused on the protection of all habitat types, especially isolated fragments in ecosystem processes.


Botany ◽  
2012 ◽  
Vol 90 (4) ◽  
pp. 293-299 ◽  
Author(s):  
Bryce A. Richardson ◽  
Susan E. Meyer

Coleogyne ramosissima Torr. (blackbrush) is a dominant xerophytic shrub species in the ecotone between the warm and cold deserts of interior western North America. Amplified fragment length polymorphisms (AFLPs) were used to survey genetic diversity and population genetic structure at 14 collection sites across the species range. Analysis revealed significant population differentiation (FST = 0.103, p < 0.0001) and reasonably high levels of genetic diversity (expected heterozygosity; HE = 0.26), a surprising result for a putative paleoendemic species. Model-based Bayesian clustering, principal coordinates analysis, and neighbor-joining analysis all produced support for the existence of two metapopulations, the first centered on the Mojave Desert and the second on the Colorado Plateau. These genetic data, coupled with information from Late Pleistocene and Holocene packrat (genus Neotoma Say and Ord, 1825) middens, illustrate a demographic history in which eastern and western distributions were disjunct during the Last Glacial Maximum and remained so through the Holocene, forming the present-day metapopulations in the Mojave Desert and Colorado Plateau. This strong regional genetic differentiation has implications for population persistence and migration in response to future climate change, as well as for shrubland restoration following anthropogenic disturbances such as annual grass invasion and wildfire.


2017 ◽  
Vol 29 (6) ◽  
pp. 499-510 ◽  
Author(s):  
Kristen B. Gorman ◽  
Sandra L. Talbot ◽  
Sarah A. Sonsthagen ◽  
George K. Sage ◽  
Meg C. Gravely ◽  
...  

AbstractAdélie penguins (Pygoscelis adeliae) are responding to ocean–climate variability throughout the marine ecosystem of the western Antarctic Peninsula (WAP) where some breeding colonies have declined by 80%. Nuclear and mitochondrial DNA (mtDNA) markers were used to understand historical population genetic structure and gene flow given relatively recent and continuing reductions in sea ice habitats and changes in numbers of breeding adults at colonies throughout the WAP. Genetic diversity, spatial genetic structure, genetic signatures of fluctuations in population demography and gene flow were assessed in four regional Adélie penguin colonies. The analyses indicated little genetic structure overall based on bi-parentally inherited microsatellite markers (FST=-0.006–0.004). No significant variance was observed in overall haplotype frequency (mtDNAΦST=0.017;P=0.112). Some comparisons with Charcot Island were significant, suggestive of female-biased philopatry. Estimates of gene flow based on a two-population coalescent model were asymmetrical from the species’ regional core to its northern range. Breeding Adélie penguins of the WAP are a panmictic population and hold adequate genetic diversity and dispersal capacity to be resilient to environmental change.


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