Satellite DNA Libraries and Centromere Evolution

ABSTRACT

Related species share a pool of satellite DNA sequences known as a satellite DNA library. Such sequences may persist in the genome for long evolutionary time at latent locations and can be amplified in any species. This leads to rapid turnover of satellite DNA composition which is characteristic for centromere evolution. The «library» hypothesis however does not predict whether any of the sequences can be amplified, and subsequently confer a centromere role. Based on structural and evolutionary studies it is proposed that satellite DNAs are highly adapted sequences whose evolution has proceeded through the combined action of natural selection and molecular drive. Their recruitment to a satellite library and retention within the genome could be related to some structural characteristics which enable them to be extended into a functional centromere array. A newly formed array could replace the previous centromere if it has some selective advantage in transmission at meiosis due to particular satellite sequence features and/or high homogeneity.

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