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What factors underlie gene reuse in adaptation?
Poštulková, Alžběta ; Bohutínská, Magdalena (advisor) ; Vosolsobě, Stanislav (referee)
Is the fate of a mutation predictable? The repeatability of evolution may indicate its predictability. If some change has emerged multiple times in the past, it may also occur in the future. Convergent evolution provides a natural model of repeated evolution and suggests the presence of certain constraints. Examination of the genetic processes, that have led to convergent adaptive traits, can contribute to the knowledge of the predictability of evolution. The aim of my work is to summarize the available knowledge about factors affecting gene reuse in adaptation. My work shows that the repeatability of evolution is biased by the genome characteristics, the population characteristics and also the trait encoding complexity. The likelihood of genomic region reuse increases with the amount of emerging mutations affecting the phenotype. Regarding the pleiotropic constraints of gene reuse, the most suitable is a mutation in the cis-regulatory region of the gene on the periphery of the functional pathway. Of the population traits, the greater effective size of the population, the higher standing genetic variation and the lower divergence between populations raise the chance of gene reuse. Despite the dependence of evolution on random processes, there are many factors that direct it and make it more...
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Signalling of personality and stress response by secondary sexual traits in a socially monogamous passerine
Tesař, David ; Tomášek, Oldřich (advisor) ; Sedláček, Ondřej (referee)
Secondary sexual traits play an irreplaceable role in the reproduction of a range of animals and are used as quality and fitness sensors during pairing of individuals. Expression of these traits, ornamentes, can correlated with an individual's personal and behavioral strategies. In the case of melanin ornaments, not only the relationships with personal individuals are considered, but there is the possible connections with stress resistance and the level of stress responses too. This hypothesis is based on the pleiotropic effect of the melanocortin system, which can be used during melanogenesis but also in the production of hormones that contribute to range of stress responses. The aim of this work was to clarify the relationship between an individual's ornaments, his stress response and individuality in the barn swallows (Hirundo rustica rustica). In this work the relationship between selected ornaments and the stress reaction of the organism, stressed glucose levels measured 15 minutes after a stress stimulus, was tested. Both sexes showed a correlation between area of white tail spots and stress response. Only for males a relationship with the length of outermost tail feathers was found and a correlation with the color saturation of feathers on the throat was shown for females. The second part of...
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