نتایج جستجو برای: clinal variation
تعداد نتایج: 296685 فیلتر نتایج به سال:
onobrychis melanotricha boiss. گونهای علفی چندساله متعلق به تیره پروانهآسا است که انحصاری ایران بوده و دارای دو واریته میباشد. در این مطالعه، 14 رولوه در زیستگاههای مختلف این گونه در استان همدان براساس روش براون-بلانکه زده شد و گونه مورد مطالعه به همراه دادههای جامعهشناختی گیاهی مربوط به رولوهها برداشت گردید. نتایج نشان میدهند که هر واریته یکی از زیستگاههای اصلی کوهپایهای یا کوهستانی ...
Adaptation to latitudinal patterns of environmental variation is predicted to result in clinal variation in leaf traits. Therefore, this study tested for geographic differentiation and plastic responses to vernalization in leaf angle and leaf morphology in Arabidopsis thaliana. Twenty-one European ecotypes were grown in a common growth chamber environment. Replicates of each ecotype were expose...
Adaptation to spatially varying environments has been studied for decades, but advances in sequencing technology are now enabling researchers to investigate the landscape of genetic variation underlying this adaptation genome wide. In this review we highlight some of the decades-long research on local adaptation in Drosophila melanogaster from well-studied clines in North America and Australia....
One of the major questions in ecology and evolutionary biology is how variation in the genome enables species to adapt to divergent environments. Here, we study footprints of thermal selection in candidate genes in six wild populations of the afrotropical butterfly Bicyclus anynana sampled along a c. 3000 km latitudinal cline. We sequenced coding regions of 31 selected genes with known function...
Conservation of water is critical to the ecological success of Drosophila species living in the drier montane localities of the Western Himalayas. We observed clinal variation in desiccation resistance for both sexes of Drosophila kikkawai from an altitudinal transect (512-2226 m above sea level). Since more than 90 per cent of body water is lost through cuticular transpiration, the target of s...
Five Indian geographical populations of Drosophila melanogaster were analyzed for their genetic divergence of life history traits. Clinal variations were observed for body weight, ovariole number, and four pre-life history traits (i.e., fecundity, hatchability, viability, and duration of development). Rearing populations at different growth temperatures shows that the variations among wild flie...
In plants, ecologically important life history traits often display clinal patterns of population divergence. Such patterns can provide strong evidence for spatially varying selection across environmental gradients but also may result from nonselective processes, such as genetic drift, population bottlenecks and spatially restricted gene flow. Comparison of population differentiation in quantit...
Clines in phenotypic traits with an underlying genetic basis potentially implicate natural selection. However, neutral evolutionary processes such as random colonization, spatially restricted gene flow, and genetic drift could also result in similar spatial patterns, especially for single-locus traits because of their susceptibility to stochastic events. One way to distinguish between adaptive ...
The occurrence of climatic adaptation in Drosophila melanogaster is highlighted by the presence of latitudinal clines in several quantitative traits, particularly clines in adult heat knockdown tolerance that is higher in tropical populations. However the presence of latitudinal patterns in physiological characteristics that may underlie these traits have rarely been assessed. Protein synthesis...
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