scholarly journals Cytotype distribution and chloroplast phylogeography of the Actinidia chinensis complex

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Zhi Wang ◽  
Caihong Zhong ◽  
Dawei Li ◽  
Chunlin Yan ◽  
Xiaohong Yao ◽  
...  
Keyword(s):  
Environmental Changes ◽  
Demographic History ◽  
Wide Distribution ◽  
Historical Demography ◽  
Actinidia Chinensis ◽  
Ecological Niche Models ◽  
Subtropical China ◽  
Modeling Tools ◽  
Climatic Fluctuations ◽  
Ploidy Levels

Abstract Background Plant phylogeographic studies of species in subtropical China have mainly focused on rare and endangered species, whereas few studies have been conducted on taxa with relatively wide distribution, especially polyploid species. We investigated the cytotype and haplotype distribution pattern of the Actinidia chinensis complex, a widespread geographically woody liana with variable ploidy in subtropical China comprising two varieties, with three chloroplast fragments DNA (ndhF-rpl132, rps16-trnQ and trnE-trnT). Macroevolutionary, microevolutionary and niche modeling tools were also combined to disentangle the origin and the demographic history of the species or cytotypes. Results The ploidy levels of 3338 individuals from 128 populations sampled throughout the species distribution range were estimated with flow cytometry. The widespread cytotypes were diploids followed by tetraploids and hexaploids, whereas triploids and octoploids occurred in a few populations. Thirty-one chloroplast haplotypes were detected. The genetic diversity and genetic structure were found to be high between varieties (or ploidy races) chinensis and deliciosa. Our results revealed that these two varieties inhabit significantly different climatic niche spaces. Ecological niche models (ENMs) indicate that all varieties’ ranges contracted during the Last Inter Glacial (LIG), and expanded eastward or northward during the Last Glacial Maximum (LGM). Conclusions Pliocene and Plio-Pleistocene climatic fluctuations and vicariance appear to have played key roles in shaping current population structure and historical demography in the A. chinensis complex. The polyploidization process also appears to have played an important role in the historical demography of the complex through improving their adaptability to environmental changes.

scholarly journals Cytotype Distribution and Chloroplast Phylogeography of Actinidia Chinensis Complex

2020 ◽  
Author(s):  
Zhi Wang ◽  
Caihong Zhong ◽  
Dawei Li ◽  
Chunlin Yan ◽  
Xiaohong Yao ◽  
...  
Keyword(s):  
Environmental Changes ◽  
Demographic History ◽  
Historical Demography ◽  
Actinidia Chinensis ◽  
Ecological Niche Models ◽  
Last Interglacial ◽  
Subtropical China ◽  
Modeling Tools ◽  
Climatic Fluctuations ◽  
Ploidy Levels

Abstract Background: Previous plant phylogeography in subtropical China mostly focused on rare and endangered species, whereas few studies conducted on the taxa with relatively wide distribution, especially for polyploid species. We used Actinidia chinensis complex, a widespread geographically woody liana of variable ploidy in subtropical China, to investigate its cytotype and haplotype distribution pattern based on three chloroplast fragments (ndhF-rpl132, ps16-trnQ and trnE-trnT). Macroevolutionary, microevolutionary and niche modeling tools were also combined to disentangle the origin and the demographic history of the species or cytotypes. Results: The ploidy levels of 3569 individuals from 128 populations sampled throughout the species distribution range were estimated using flow cytometry. The widespread cytotypes were diploids followed by tetraploids and hexaploids, while triploids and octaploids occasionally occurred in a few populations. Thirty-one chloroplast haplotypes were detected and the genetic diversity and genetic structure were great differences between the var. chinensis and var. deliciosa. Our results also revealed these two varieties (or ploidy races) inhabit significantly different climatic niche spaces. Ecological niche models (ENMs) indicate that all varieties’ ranges contracted during the Last Interglacial (LIG), and expanded eastward or northward during the Last Glacial Maximum (LGM). Conclusions: Pliocene and Plio-Pleistocene climatic fluctuations and vicariance may have played key roles in shaping the current population structure and historical demography in the A. chinensis complex. The polyploidization process also played an important role in the historical demography of the A. chinensis complex through improving their adaptability to environmental changes.

scholarly journals Demographic history and genomic response to environmental changes in a rapid radiation of wild rats

2021 ◽  
Author(s):  
Deyan Ge ◽  
Anderson Feijó ◽  
Zhixin Wen ◽  
Alexei V Abramov ◽  
Liang Lu ◽  
...  
Keyword(s):  
Environmental Changes ◽  
Demographic History ◽  
Terrestrial Ecosystems ◽  
Tibet Plateau ◽  
Global Changes ◽  
Rapid Radiation ◽  
Protein Functions ◽  
Wild Rats ◽  
Qinghai Tibet Plateau ◽  
Genomic Response

Abstract For organisms to survive and prosper in a harsh environment, particularly under rapid climate change, poses tremendous challenges. Recent studies have highlighted the continued loss of megafauna in terrestrial ecosystems and the subsequent surge of small mammals, such as rodents, bats, lagomorphs, and insectivores. However, the ecological partitioning of these animals will likely lead to large variation in their responses to environmental change. In the present study, we investigated the evolutionary history and genetic adaptations of white-bellied rats (Niviventer Marshall, 1976), which are widespread in the natural terrestrial ecosystems in Asia but also known as important zoonotic pathogen vectors and transmitters. The southeastern Qinghai-Tibet Plateau (QHTP) was inferred as the origin center of this genus, with parallel diversification in temperate and tropical niches. Demographic history analyses from mitochondrial and nuclear sequences of Niviventer demonstrated population size increases and range expansion for species in Southeast Asia, and habitat generalists elsewhere. Unexpectedly, population increases were seen in N. eha, which inhabits the highest elevation among Niviventer species. Genome scans of nuclear exons revealed that among the congeneric species, N. eha has the largest number of positively selected genes. Protein functions of these genes are mainly related to olfaction, taste and tumor suppression. Extensive genetic modification presents a major strategy in response to global changes in these alpine species.

scholarly journals Ecological opportunities and specializations shaped genetic divergence in a highly mobile marine top predator

2014 ◽  
Vol 281 (1795) ◽  
pp. 20141558 ◽  
Author(s):  
Marie Louis ◽  
Michael C. Fontaine ◽  
Jérôme Spitz ◽  
Erika Schlund ◽  
Willy Dabin ◽  
...  
Keyword(s):  
Population Structure ◽  
Mediterranean Sea ◽  
Environmental Changes ◽  
Demographic History ◽  
World Ocean ◽  
Ecological Niches ◽  
Morphological Divergence ◽  
Evolutionary Diversification ◽  
The Mediterranean ◽  
Population Demographic

Environmental conditions can shape genetic and morphological divergence. Release of new habitats during historical environmental changes was a major driver of evolutionary diversification. Here, forces shaping population structure and ecotype differentiation (‘pelagic’ and ‘coastal’) of bottlenose dolphins in the North-east Atlantic were investigated using complementary evolutionary and ecological approaches. Inference of population demographic history using approximate Bayesian computation indicated that coastal populations were likely founded by the Atlantic pelagic population after the Last Glacial Maxima probably as a result of newly available coastal ecological niches. Pelagic dolphins from the Atlantic and the Mediterranean Sea likely diverged during a period of high productivity in the Mediterranean Sea. Genetic differentiation between coastal and pelagic ecotypes may be maintained by niche specializations, as indicated by stable isotope and stomach content analyses, and social behaviour. The two ecotypes were only weakly morphologically segregated in contrast to other parts of the World Ocean. This may be linked to weak contrasts between coastal and pelagic habitats and/or a relatively recent divergence. We suggest that ecological opportunity to specialize is a major driver of genetic and morphological divergence. Combining genetic, ecological and morphological approaches is essential to understanding the population structure of mobile and cryptic species.

scholarly journals Reef development and Sea level changes drive Acanthaster Population Expansion in the Indo-Pacific region

2020 ◽  
Author(s):  
P.C. Pretorius ◽  
T.B. Hoareau
Keyword(s):  
Population Size ◽  
Sea Level ◽  
Environmental Changes ◽  
Sequence Data ◽  
Demographic History ◽  
Population Expansion ◽  
Population Level ◽  
Sea Level Changes ◽  
Reef Development ◽  
Curve Fitting Method

AbstractMolecular clock calibration is central in population genetics as it provides an accurate inference of demographic history, whereby helping with the identification of driving factors of population changes in an ecosystem. This is particularly important for coral reef species that are seriously threatened globally and in need of conservation. Biogeographic events and fossils are the main source of calibration, but these are known to overestimate timing and parameters at population level, which leads to a disconnection between environmental changes and inferred reconstructions. Here, we propose the Last Glacial Maximum (LGM) calibration that is based on the assumptions that reef species went through a bottleneck during the LGM, which was followed by an early yet marginal increase in population size. We validated the LGM calibration using simulations and genetic inferences based on Extended Bayesian Skyline Plots. Applying it to mitochondrial sequence data of crown-of-thorns starfish Acanthaster spp., we obtained mutation rates that were higher than phylogenetically based calibrations and varied among populations. The timing of the greatest increase in population size differed slightly among populations, but all started between 10 and 20 kya. Using a curve-fitting method, we showed that Acanthaster populations were more influenced by sea-level changes in the Indian Ocean and by reef development in the Pacific Ocean. Our results illustrate that the LGM calibration is robust and can probably provide accurate demographic inferences in many reef species. Application of this calibration has the potential to help identify population drivers that are central for the conservation and management of these threatened ecosystems.

scholarly journals Population Dynamics in Pre-Modern China

2013 ◽  
Author(s):  
Zhongwei Zhao
Keyword(s):  
Economic Development ◽  
Population Growth ◽  
Chinese Population ◽  
Environmental Changes ◽  
Demographic History ◽  
Social Institutions ◽  
Population History ◽  
Chinese History ◽  
Population Changes ◽  
The Past

China constituted one of the earliest civilizations in the world. During most of the past two millennia, China was also one of the most advanced economies and the home of around a quarter of the world’s population. By the start of the first millennium, the Chinese population was already about sixty million. In the next two thousand years, China’s population growth and economic development significantly influenced the world’s population changes and history. Partly for these reasons, in the study of population and social history, China’s historical population growth, demographic regimes, marriage patterns, and household formation systems are frequently used as examples in the discussion of population changes, microsocial structure, and their relationships with natural resources and economic development in past times. Population changes were one of the key components of Chinese history. The size and density of the population, the rise and fall of fertility and mortality, and the increase and decrease of population movements were not only related to demographic factors such as age structure. They were also strongly affected by political and economic conditions, social institutions and cultural traditions, and natural and social environments. Therefore, studies of demographic history, those conducted recently in particular, often shed new light on economic, political, social, and environmental changes in the past. This bibliography, through reviewing major works published in Chinese and English, provides an introduction to China’s main historical population data sources, major research questions, and debates in the study of Chinese population history. It also introduces recent advances in Chinese historical demography and important research findings made by these developments.

DEMOGRAPHIC HISTORY OF THE USSR IN THE 1920-1930S: ON THE PROBLEM OF MODERN HISTORIOGRAPHY

2020 ◽  
Vol 65 (4) ◽  
pp. 15-21
Author(s):  
EKATERINA N. BADMAEVA ◽  
◽  
ELLARA U. OMAKAEVA ◽  
Keyword(s):  
Demographic History ◽  
Historical Demography ◽  
Historical Science ◽  
Demographic Process ◽  
Historical Factors ◽  
Scientific Papers ◽  
History Of ◽  
Key Issues

The article discusses the main trends in the formation and development of a new direction of historical science - historical demography. The purpose of the article is to review scientific papers related to the study of the stated issues. Their general characteristics are given, and key issues are highlighted. The role and significance of socio - historical factors in the demographic process of the first half of the XX century in different regions of the USSR on the example of Kalmykia, Ukraine and Kazakhstan are revealed. A historiographical assessment of losses during the demographic crisis in the USSR in the first half of the 1930s is given.

The impact of Dansgaard–Oeschger cycles on the loessic environment and malacofauna of Nussloch (Germany) during the Upper Weichselian

2008 ◽  
Vol 70 (1) ◽  
pp. 91-104 ◽  
Author(s):  
Olivier Moine ◽  
Denis-Didier Rousseau ◽  
Pierre Antoine
Keyword(s):  
Grain Size ◽  
Environmental Changes ◽  
Ice Core ◽  
Schematic Model ◽  
Climatic Fluctuations ◽  
Climatic Oscillations ◽  
The North ◽  
Size Index ◽  
The Impact ◽  
Hygrophilous Species

AbstractA loess sequence has been sampled continuously at high resolution in Nussloch (Rhine Valley, Germany) for malacological and grain-size analyses between ca. 34 and 20 ka. Molluscan abundance and richness, percentage in hygrophilous species and grain-size index show cyclical variations related to the lithological loess–gley alternation. Major molluscan abundance maxima were triggered by temperature increases through an enhancement of the reproduction cycle, whereas cyclical richness fluctuations and percentage in hygrophilous species reflect variations in local humidity and changes in the environmental mosaic. Malacological parameters allow the distinction of four environmental phases organised in cyclical successions correlated with most of the loess–gley doublets. The correlation of the grain-size index of the Nussloch loess sequence with the dust content of the GRIP ice core demonstrates the synchronicity of major molluscan abundance maxima and δ18O increases characterising temperature increases during Dansgaard–Oeschger interstades. A schematic model is proposed to link the North Atlantic Dansgaard–Oeschger climatic oscillations with local environmental changes indicated by both malacofauna and pedostratigraphy. This malacological study of the Nussloch loess sequence thus provides new information about the response of terrestrial loessic palaeoenvironments to millennial-timescale climatic fluctuations during the Upper Weichselian (∼ marine isotope stage 2 (MIS 2) and end of MIS 3).

scholarly journals Xylem anatomy needs to change, so that conductivity can stay the same: xylem adjustments across elevation and latitude in Nothofagus pumilio

2020 ◽  
Vol 125 (7) ◽  
pp. 1101-1112
Author(s):  
Ana I García-Cervigón ◽  
Alex Fajardo ◽  
Cristina Caetano-Sánchez ◽  
J Julio Camarero ◽  
José Miguel Olano
Keyword(s):  
Hydraulic Conductivity ◽  
Individual Variation ◽  
Environmental Changes ◽  
Vessel Diameter ◽  
Vessel Density ◽  
Nothofagus Pumilio ◽  
Widespread Species ◽  
Climatic Fluctuations ◽  
Wide Range ◽  
Diameter Distributions

Abstract Background and Aims Plants have the potential to adjust the configuration of their hydraulic system to maintain its function across spatial and temporal gradients. Species with wide environmental niches provide an ideal framework to assess intraspecific xylem adjustments to contrasting climates. We aimed to assess how xylem structure in the widespread species Nothofagus pumilio varies across combined gradients of temperature and moisture, and to what extent within-individual variation contributes to population responses across environmental gradients. Methods We characterized xylem configuration in branches of N. pumilio trees at five sites across an 18° latitudinal gradient in the Chilean Andes, sampling at four elevations per site. We measured vessel area, vessel density and the degree of vessel grouping. We also obtained vessel diameter distributions and estimated the xylem-specific hydraulic conductivity. Xylem traits were studied in the last five growth rings to account for within-individual variation. Key Results Xylem traits responded to changes in temperature and moisture, but also to their combination. Reductions in vessel diameter and increases in vessel density suggested increased safety levels with lower temperatures at higher elevation. Vessel grouping also increased under cold and dry conditions, but changes in vessel diameter distributions across the elevational gradient were site-specific. Interestingly, the estimated xylem-specific hydraulic conductivity remained constant across elevation and latitude, and an overwhelming proportion of the variance of xylem traits was due to within-individual responses to year-to-year climatic fluctuations, rather than to site conditions. Conclusions Despite conspicuous adjustments, xylem traits were coordinated to maintain a constant hydraulic function under a wide range of conditions. This, combined with the within-individual capacity for responding to year-to-year climatic variations, may have the potential to increase forest resilience against future environmental changes.

scholarly journals Genome resequencing reveals demographic history and genetic architecture of seed salinity tolerance in Populus euphratica

2020 ◽  
Vol 71 (14) ◽  
pp. 4308-4320 ◽  
Author(s):  
Huixia Jia ◽  
Guangjian Liu ◽  
Jianbo Li ◽  
Jin Zhang ◽  
Pei Sun ◽  
...  
Keyword(s):  
Single Nucleotide Polymorphisms ◽  
Salinity Tolerance ◽  
Genetic Architecture ◽  
Demographic History ◽  
Populus Euphratica ◽  
Tectonic Deformation ◽  
Nucleotide Polymorphisms ◽  
Genome Resequencing ◽  
Single Nucleotide ◽  
Climatic Fluctuations

Abstract Populus euphratica is a dominant tree species in desert riparian forests and possesses extraordinary adaptation to salinity stress. Exploration of its genomic variation and molecular underpinning of salinity tolerance is important for elucidating population evolution and identifying stress-related genes. Here, we identify approximately 3.15 million single nucleotide polymorphisms using whole-genome resequencing. The natural populations of P. euphratica in northwest China are divided into four distinct clades that exhibit strong geographical distribution patterns. Pleistocene climatic fluctuations and tectonic deformation jointly shaped the extant genetic patterns. A seed germination rate-based salinity tolerance index was used to evaluate seed salinity tolerance of P. euphratica and a genome-wide association study was implemented. A total of 38 single nucleotide polymorphisms were associated with seed salinity tolerance and were located within or near 82 genes. Expression profiles showed that most of these genes were regulated under salt stress, revealing the genetic complexity of seed salinity tolerance. Furthermore, DEAD-box ATP-dependent RNA helicase 57 and one undescribed gene (CCG029559) were demonstrated to improve the seed salinity tolerance in transgenic Arabidopsis. These results provide new insights into the demographic history and genetic architecture of seed salinity tolerance in desert poplar.

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