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Population differentiation of Ochrophytes
Mensová, Anna ; Jurdíková, Katarína (advisor) ; Kulichová, Jana (referee)
This bachelor thesis deals with a differentiation of populations of Ochrophytes (photosynthetic Stramenopiles). Natural populations can differ in many aspects and their differentiation is observed on several levels. Ecophysiological and morphological differences are very often caused by phenotypic plasticity, which is a flexible answer to changing conditions of habitats. Genetic differentiation could express an adaptation to the local environmental conditions. The adaptation and a long-term isolation of populations are considered to be the leading factors in genetic differentiation. The other factors contributing to genetic differentiation are random evolutionary events such as founder effect or genetic drift. Detailed studies of populations lead to uncover the factors that cause the differentiation of populations as well as they contribute to the understanding of speciation mechanisms. The thesis compiled the information about different types of variability among populations within the classes of Ochrophytes.
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Population differentiation of Ochrophytes
Mensová, Anna ; Jurdíková, Katarína (advisor) ; Kulichová, Jana (referee)
This bachelor thesis deals with a differentiation of populations of Ochrophytes (photosynthetic Stramenopiles). Natural populations can differ in many aspects and their differentiation is observed on several levels. Ecophysiological and morphological differences are very often caused by phenotypic plasticity, which is a flexible answer to changing conditions of habitats. Genetic differentiation could express an adaptation to the local environmental conditions. The adaptation and a long-term isolation of populations are considered to be the leading factors in genetic differentiation. The other factors contributing to genetic differentiation are random evolutionary events such as founder effect or genetic drift. Detailed studies of populations lead to uncover the factors that cause the differentiation of populations as well as they contribute to the understanding of speciation mechanisms. The thesis compiled the information about different types of variability among populations within the classes of Ochrophytes.
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Genetic variation and differentiation of the Eurasian reed warbler \kur{(Acrocephalus scirpaceus)}
FAINOVÁ, Drahomíra
Eurasian Reed Warbler (Acrocephalus scirpaceus) is a long-distance migrant wintering in sub-Saharan Africa and breeding in reedbeds of the Western Palaearctic. European populations migrate in two main directions (SW and SE). Though there is little morphological variation across the breeding range, Asian populations are traditionally separated from the nominate subspecies as the subspecies fuscus. My aim was to explore genetic differentiation among Eurasian Reed Warbler populations in respect to the factors which may have influenced the genetic diversity and divergence of the populations, such as a migratory divide, high migratory connectivity or isolation by distance. I used samples of 495 individuals from 36 populations across the breeding range using microsatellites. Pairwaise fixation indexes FST showed significant differences among populations from the Iberian peninsula, Finland and the Middle East and the rest of populations. Exact tests of differentiation did not confirm non-random distribution between pairs of populations. Overall FST was statistical significant but very small (FST = 0,018). Analysis of molecular variance (AMOVA) revealed that 98% of variation was ascribable to variability of allele frequencies within populations. On the other hand, differences between populations contributed to overall variation with only 2%. Isolation by distance showed only weak relationship between geographical and genetic distances. Main analysis using Bayesian clustering approach implemented in software Structure 2.2. detected no genetic structure of population. Sampled Eurasian Reed Warbler populations seem to form one genetic population. Relatively low genetic diversification indicates large dispersal potential of the studied Reed Warbler populations, when gene flow successfully counters differentiation of population irrespective of large breeding area and high migrate connectivity between breeding and wintering area.
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