Genetic Structure of the Frogs Geocrinia lutea and Geocrinia rosea Reflects Extreme Population Divergence and Range Changes, Not Dispersal Barriers

Evolution ◽  
1998 ◽  
Vol 52 (4) ◽  
pp. 1147 ◽  
Author(s):  
Don A. Driscoll
Keyword(s):  
Genetic Structure ◽  
Population Divergence ◽  
Dispersal Barriers

scholarly journals Does selection occur at the intermediate zone of two insufficiently isolated populations? A whole-genome analysis along an altitudinal gradient

2021 ◽  
Author(s):  
Naofumi Yoshida ◽  
Shin-Ichi Morinaga ◽  
Takeshi Wakamiya ◽  
Yuu Ishii ◽  
Shosei Kubota ◽  
...  
Keyword(s):  
Gene Flow ◽  
Genetic Structure ◽  
Altitudinal Gradient ◽  
Intermediate Zone ◽  
Adaptive Divergence ◽  
Population Divergence ◽  
Whole Genome ◽  
Isolated Populations ◽  
Whole Genome Analysis ◽  
Single Nucleotide

Abstract Adaptive divergence would occur even between the insufficiently isolated populations when there is a great difference in the environments of their habitats. The individuals present in the intermediate zone of the two divergent populations are expected to have an admixed genetic structure due to gene flow. A selective pressure that acts on the genetically admixed individuals may limit the gene flow and promote the adaptive divergence. Here, we addressed a question whether the selection occurs in the genetically admixed individuals between the divergent populations and assessed its effects on the population divergence. We obtained the whole-genome sequences of a perennial montane plant, Arabidopsis halleri, which has clear phenotypic dimorphisms between altitudes, along an altitudinal gradient of 359–1,317 m with a high spatial resolution (mean altitudinal interval of 20 m). We found the zone where the highland and lowland genes were mixing. Using the FST approach, we found that 35 and 13 genes in the admixed zone had a high frequency of alleles that are accumulated in highland and lowland subpopulations, respectively, suggesting that these genes have been selected in the admixed zone. This selection might limit the gene flow and contribute to the adaptive divergence along the altitudes. In the single-nucleotide polymorphism (SNP)-based analysis, 3,000 out of 27,792 Altitude-Dependent SNPs had extremely high homozygosity in the admixed zone. In 84.7% of these SNPs, the frequency of homozygotes of highland alleles was comparable to that of lowland alleles, suggesting that these alleles are neutral but the heterozygotes were selectively eliminated. The distribution of highland and lowland alleles of these SNPs was not clearly separated between altitudes, implying that such selection did not impede the gene flow. We conclude that the selection occurring at the intermediate altitude affects the genetic structure in the admixed zone and adaptive divergence along the altitudes.

scholarly journals Genetic variation and cryptic lineage diversity of the Nigerian red-headed rock agama Agama agama associate with eco-geographic zones

2019 ◽  
Vol 65 (6) ◽  
pp. 713-724 ◽  
Author(s):  
Lotanna M Nneji ◽  
Adeniyi C Adeola ◽  
Fang Yan ◽  
Agboola O Okeyoyin ◽  
Ojo C Oladipo ◽  
...  
Keyword(s):  
Genetic Structure ◽  
Geographic Distance ◽  
Climatic Conditions ◽  
Population Divergence ◽  
Geographic Isolation ◽  
Genetic Structuring ◽  
Derived Savanna ◽  
Wide Range ◽  
Conservation Actions ◽  
The Impact

AbstractNigeria is an Afrotropical region with considerable ecological heterogeneity and levels of biotic endemism. Among its vertebrate fauna, reptiles have broad distributions, thus, they constitute a compelling system for assessing the impact of ecological variation and geographic isolation on species diversification. The red-headed rock agama, Agama agama, lives in a wide range of habitats and, thus, it may show genetic structuring and diversification. Herein, we tested the hypothesis that ecology affects its genetic structure and population divergence. Bayesian inference phylogenetic analysis of a mitochondrial DNA (mtDNA) gene recovered four well-supported matrilines with strong evidence of genetic structuring consistent with eco-geographic regions. Genetic differences among populations based on the mtDNA also correlated with geographic distance. The ecological niche model for the matrilines had a good fit and robust performance. Population divergence along the environmental axes was associated with climatic conditions, and temperature ranked highest among all environmental variables for forest specialists, while precipitation ranked highest for the forest/derived savanna, and savanna specialists. Our results cannot reject the hypothesis that niche conservatism promotes geographic isolation of the western populations of Nigerian A. agama. Thus, ecological gradients and geographic isolation impact the genetic structure and population divergence of the lizards. This species might be facing threats due to recent habitat fragmentation, especially in western Nigeria. Conservation actions appear necessary.

scholarly journals Genomic Adaptive Evolution of Sand Rice (Agriophyllum squarrosum) and Its Implications for Desert Ecosystem Restoration

2021 ◽  
Vol 12 ◽  
Author(s):  
Chaoju Qian ◽  
Xia Yan ◽  
Tingzhou Fang ◽  
Xiaoyue Yin ◽  
Shanshan Zhou ◽  
...  
Keyword(s):  
Genetic Structure ◽  
Balancing Selection ◽  
Desert Ecosystem ◽  
Ecological Niches ◽  
Population Divergence ◽  
Desert Plants ◽  
Agriophyllum Squarrosum ◽  
Heterogeneous Habitats ◽  
Wide Range ◽  
Sand Rice

Natural selection is a significant driver of population divergence and speciation of plants. Due to local adaptation to geographic regions with ecological gradients, plant populations harbored a wide range of adaptive genetic variation to enable them to survive the heterogeneous habitats. This is all the more necessary for desert plants, as they must tolerant more striking gradients of abiotic stresses. However, the genomic mechanism by which desert plants adapt to ecological heterogeneity remains unclear, which could help to guide the sustainability of desert ecosystems. Here, using restriction-site-associated DNA sequencing in 38 natural populations, we investigated the genomic divergence and environmental adaptation of sand rice, Agriophyllum squarrosum, an annual pioneer species that covers sand dunes in northern China. Population genetic structure analyses showed that sand rice could be divided into three geographically distinct lineages, namely, Northwest, Central, and East. Phylogeographic analyses revealed that the plant might originate locally in Bergen County and further differentiated into the East lineage and then the Central lineage. Ecological niche modeling found that different lineages occupied distinct ecological niches, suggesting that the ecological gradient would have triggered genomic differentiation among sand rice lineages. Ecological association study supported that the three SNPs under divergent selection were closely correlated with precipitation gradients, indicating that precipitation might be the most important stress trigger for lineage diversity in sand rice. These adaptive SNPs could be used to genotype suitable germplasms for the ecological restoration of specific desertified lands. Further analyses found that genetic structure could significantly overestimate the signals for balancing selection. Within the Central lineage, we still found that 175 SNPs could be subject to balancing selection, which could be the means by which sand rice maintains genetic diversity and adapts to multiple stresses across heterogeneous deserts and sandy lands. From a genomic point of view, this study highlighted the local and global adaptation patterns of a desert plant to extreme and heterogeneous habitats. Our data provide molecular guidance for the restoration of desertified lands in the arid and semi-arid regions of China and could facilitate the marker assistant breeding of this potential crop to mitigate climate change.

Is phenotypic variation reflected in habitat connectivity? A morphometric comparison of two moss species from insular and continuous habitats of the Amazon Basin

2017 ◽  
Vol 39 (1) ◽  
pp. 102 ◽  
Author(s):  
ANNA KELLY N. C. DA SILVA ◽  
CRISTIAN DE S. DAMBROS ◽  
MARTA R. PEREIRA ◽  
CHARLES E. ZARTMAN
Keyword(s):  
Genetic Structure ◽  
Phenotypic Variation ◽  
Environmental Variables ◽  
Amazon Basin ◽  
Habitat Connectivity ◽  
Population Divergence ◽  
Terra Firme ◽  
Moss Species ◽  
Continental Scale ◽  
White Sands

The influence of habitat connectivity on dispersal limitation and genetic structure in bryophytes is relatively well researched; however, little is known as to how habitat insularity may impact phenotypic divergences on a continental scale. Here we conduct a morphometric analysis of five quantitative gametophytic traits from two Amazonian Calymperaceae (Syrrhopodon helicophyllus and Calymperes lonchophyllum) from contrasting habitats (Amazonian white-sands and terra firme forests) to test whether increased habitat insularity is correlated with greater inter-population divergence in phenotypic variation. We also test how much of the phenotypic variation among the two taxa is explained by three environmental variables (altitude, mean annual temperature and mean annual precipitation). The Amazonian species endemic to continuous terra-firme forest (C. lonchophyllum) revealed greater geographic structure in phenotypic variation that that of its counterpart (S. helicophyllus) of more insular white-sands forest habitats. Furthermore, environmental variables explained more of the phenotypic variation among populations of S. helicophyllus than for those of C. lonchophyllum. We attempt to explain these patterns as a result of either historical factors, divergent adaptive reproductive strategies, phenotypic plasticity and/or differences in the spatial scales of sampling effort among the two species. Understanding the role of habitat heterogeneity on speciation processes is a priority for understanding the origin and maintenance of floristic richness in the Amazon Basin. We propose that bryophyte studies highlighting morphometric data coupled with population genetic structure would greatly contribute to our understanding of evolutionary processes in this megadiverse Biome.

Effects of dispersal barriers and geographic distance on the genetic structure of a narrowly distributed frog in a spatially structured landscape

2019 ◽  
Vol 309 (4) ◽  
pp. 295-309
Author(s):  
T. Pan ◽  
K. Zhou ◽  
S.‐L. Zhang ◽  
Y.‐L. Shu ◽  
J.‐H. Zhang ◽  
...  
Keyword(s):  
Genetic Structure ◽  
Geographic Distance ◽  
Dispersal Barriers

scholarly journals Phylogeography, genetic structure and population divergence time of cheetahs in Africa and Asia: evidence for long-term geographic isolates

2011 ◽  
Vol 20 (4) ◽  
pp. 706-724 ◽  
Author(s):  
P. CHARRUAU ◽  
C. FERNANDES ◽  
P. OROZCO-terWENGEL ◽  
J. PETERS ◽  
L. HUNTER ◽  
...  
Keyword(s):  
Genetic Structure ◽  
Divergence Time ◽  
Population Divergence

scholarly journals Genetic Structure and Hierarchical Population Divergence History of Acer mono var. mono in South and Northeast China

PLoS ONE ◽  
2014 ◽  
Vol 9 (1) ◽  
pp. e87187 ◽  
Author(s):  
Chunping Liu ◽  
Yoshiaki Tsuda ◽  
Hailong Shen ◽  
Lijiang Hu ◽  
Yoko Saito ◽  
...  
Keyword(s):  
Genetic Structure ◽  
Northeast China ◽  
Population Divergence ◽  
History Of ◽  
Acer Mono
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