engleski

Centromere-Competent DNA: Structure and Evolution

Although extant data favour centromere being epigenetic structure it is also clear that centromere formation is based on DNA, in particular tandemly repeated satellite DNA and its transcripts. Presence of conserved structural motifs within satellite DNAs such as periodically distributed AT tracts, protein binding sites or promoter elements indicate that despite sequence flexibility, there are structural determinants which are prerequisite for centromere function. In addition, existence of functional centromeric DNA transcripts indicates possible importance of structural elements at the level of RNA secondary or tertiary structure. Rapid centromere evolution is explained by homologous recombination followed by extrachromosomal rolling circle replication. This could lead to amplification of different satellite sequences within a genome. However, only those satellites which have inherent centromere-competence in the form of structural requirements necessary for centromere function are after amplification fixed in a population as a new centromere.

centromere, chromosome, evolution

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