Vinsamlegast notið þetta auðkenni þegar þið vitnið til verksins eða tengið í það: http://hdl.handle.net/1946/13953
Complex gene regulatory networks are central to the development of multicellular organisms. Trancriptional regulation is considered the most common mechanism of gene regulation. cis – elements are parts of DNA that proteins (transcription factors) bind to and activate and repress transcription. These regulatory elements are composed of a multiple short binding sites for more than one factor. Changes in gene regulation has been proposed to be the main contributor to evolution. Characterized binding sites within enhancers are generally well conserved and few mutations have been documented. Preliminary data show, two separate deletions of two conserved binding sites for Hunchback (HB) in an enhancer for even-skipped in Drosophila melanogaster.
To explain these deletions we proposed a model of co-evolution. We hypothesized that the concentration of HB had changed, the expression shifted or the timing of expression had changed and the deletions are a response to such a shift of the protein. We also expect to see higher incidence of mutations in HB sites genome-wide. We used population genetic and bioinformatic methods to study this, namely genome wide ChIP-chip data and sequences of ~200 inbred strains of Drosophila melanogaster. There is no excess of HB sites affected by SNPs compared to reference factors. We did however, see a higher fraction of deletions in HB binding sites. In sum the evidence are not conclusive on our hypothesis but confirms that a lot of predicted binding sites are affected by mutations.
|Testing for co-evolution between eve and Hunchback in D. melanogaster.pdf||9.76 MB||Opinn||Heildartexti||Skoða/Opna|