Search results for "Selecció natural"
showing 4 items of 4 documents
A feedback mechanism controls rDNA copy number evolution in yeast independently of natural selection.
2022
Ribosomal DNA (rDNA) is the genetic loci that encodes rRNA in eukaryotes. It is typically arranged as tandem repeats that vary in copy number within the same species. We have recently shown that rDNA repeats copy number in the yeast Saccharomyces cerevisiae is controlled by cell volume via a feedback circuit that senses cell volume by means of the concentration of the free upstream activator factor (UAF). The UAF strongly binds the rDNA gene promoter, but is also able to repress SIR2 deacetylase gene transcription that, in turn, represses rDNA amplification. In this way, the cells with a smaller DNA copy number than what is optimal evolve to increase that copy number until they reach a numb…
Temperature as a modulator of sexual selection
2018
A central question in ecology and evolution is to understand why sexual selection varies so much in strength across taxa; it has long been known that ecological factors are crucial to this. Temperature is a particularly salient abiotic ecological factor that modulates a wide range of physiological, morphological and behavioural traits, impacting individuals and populations at a global taxonomic scale. Furthermore, temperature exhibits substantial temporal variation (e.g. daily, seasonally and inter-seasonally), and hence for most species in the wild sexual selection will regularly unfold in a dynamic thermal environment. Unfortunately, studies have so far almost completely neglected the rol…
Processos i mecanismes evolutius: Pràctiques d'informàtica
2016
S'inclouen dues pràctiques informàtiques amb el software docent de lliure distribució Populus. Les pràctiques tenen com a objectiu familiaritzar l'estudiant amb els processos de selecció natural i deriva genètica aleatòria mitjançant simulacions computacionals. L'estudiant haurà de resoldre qüestions pràctiques.
Processos i Mecanismes Evolutius: Problemes
2016
S´inclouen dues enunciats de problemes de genètica de poblacions, que permetran l´estudiant aprofundir en els conceptes de equilibri de Hardy-Weinberg, selecció natural, deriva genètica aleatòria, mutació, migració i endogàmia.