نتایج جستجو برای: geographical populations

تعداد نتایج: 283132  

Journal: :Molecular ecology 2017
Francisco Morinha José A Dávila Estela Bastos João A Cabral Óscar Frías José L González Paulo Travassos Diogo Carvalho Borja Milá Guillermo Blanco

Social barriers have been shown to reduce gene flow and contribute to genetic structure among populations in species with high cognitive capacity and complex societies, such as cetaceans, apes and humans. In birds, high dispersal capacity is thought to prevent population divergence unless major geographical or habitat barriers induce isolation patterns by dispersal, colonization or adaptation l...

2002
H KING D E CONLONG A MITCHELL

The sugarcane stemborer Eldana saccharina is an indigenous African moth found throughout much of subsaharan Africa. Previous research has revealed ecological differences among geographical populations, raising the possibility that E. saccharina may consist of different biotypes. As a first step towards evaluating this hypothesis, E. saccharina populations from across Africa were surveyed for mi...

2015
Scott Bennett Thomas Wernberg Bijo Arackal Joy Thibaut de Bettignies Alexandra H Campbell

Rear (warm) edge populations are often considered more susceptible to warming than central (cool) populations because of the warmer ambient temperatures they experience, but this overlooks the potential for local variation in thermal tolerances. Here we provide conceptual models illustrating how sensitivity to warming is affected throughout a species' geographical range for locally adapted and ...

Journal: :Journal of evolutionary biology 2011
C D Cadena Z A Cheviron W C Funk

Understanding the mechanisms accounting for the evolution of phenotypic diversity is central to evolutionary biology. We use molecular and phenotypic data to test hypotheses for 'leapfrog' patterns of geographical variation, in which phenotypically similar, disjunct populations are separated by distinct populations of the same species. Phylogenetic reconstructions revealed independent evolution...

Journal: :Proceedings. Biological sciences 2013
Robert M Ross Simon J Greenhill Quentin D Atkinson

Despite a burgeoning science of cultural evolution, relatively little work has focused on the population structure of human cultural variation. By contrast, studies in human population genetics use a suite of tools to quantify and analyse spatial and temporal patterns of genetic variation within and between populations. Human genetic diversity can be explained largely as a result of migration a...

2016
Błażej Wójkiewicz Monika Litkowiec Witold Wachowiak

Gene flow tends to have a homogenising effect on a species' background genetic variation over large geographical areas. However, it is usually unknown to what extent the genetic structure of populations is influenced by gene exchange between core and peripheral populations that may represent stands of different evolutionary and demographic history. In this study, we looked at the patterns of po...

2005
V. Schwammle A. O. Sousa S. M. de Oliveira

Parapatric speciation is studied using an individual–based model with sexual reproduction. We combine the theory of mutation accumulation for biological ageing with an environmental selection pressure that varies according to the individuals geographical positions and phenotypic traits. Fluctuations and genetic diversity of large populations are crucial ingredients to model the features of evol...

Journal: :Molecular ecology 2011
Ron J Etter Elizabeth E Boyle Amanda Glazier Robert M Jennings Ediane Dutra Mike R Chase

The deep sea is a vast and essentially continuous environment with few obvious barriers to gene flow. How populations diverge and new species form in this remote ecosystem is poorly understood. Phylogeographical analyses have begun to provide some insight into evolutionary processes at bathyal depths (<3000 m), but much less is known about evolution in the more extensive abyssal regions (>3000 ...

2013
Xianyun Sun Shu Kang Yongjie Zhang Xinqiu Tan Yufei Yu Haiyong He Xinyu Zhang Yongfeng Liu Shu Wang Wenxian Sun Lei Cai Shaojie Li

Rice false smut caused by the fungal pathogen Ustilaginoidea virens is becoming a destructive disease throughout major rice-growing countries. Information about its genetic diversity and population structure is essential for rice breeding and efficient control of the disease. This study compared the genome sequences of two U. virens isolates. Three SNP-rich genomic regions were identified as mo...

2016
Tiphaine Maurice Diethart Matthies Serge Muller Guy Colling

Due to land-use intensification, lowland and colline populations of many plants of nutrient-poor grasslands have been strongly fragmented in the last decades, with potentially negative consequences for their genetic diversity and persistence. Populations in mountains might represent a genetic reservoir for grassland plants, because they have been less affected by land-use changes. We studied th...

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