The Evolution of Tandemly Repetitive DNA: Recombination Rules
AUTOR(ES)
Harding, R. M.
RESUMO
Variable numbers of tandem repeats (VNTRs), which include hypervariable regions, minisatellites and microsatellites, can be assigned together with satellite DNAs to define a class of noncoding tandemly repetitive DNA (TR-DNA). The evolution of TR-DNA is assumed to be driven by an unbiased recombinational process. A simulation model of unequal exchange is presented and used to investigate the evolutionary persistence of single TR-DNA lineages. Three different recombination rules are specified to govern the expansion and contraction of a TR-DNA lineage from an initial array of two repeats to, finally, a single repeat allele, which cannot participate in a misalignment and exchange process. In the absence of amplification or selection acting to bias array evolution toward expansion, the probability of attaining a target array size is a function only of the initial number of repeats. We show that the proportions of lineages attaining a targeted array size are the same irrespective of recombination rule and rate, demonstrating that our simulation model is well behaved. The time taken to attain a target array size, the persistence of the target array, and the total persistence time of repetitive array structure, are functions of the initial number of repeats, the rate of recombination, and the rules of misalignment preceding recombinational exchange. These relationships are investigated using our simulation model. While misalignment contraint is probably greatest for satellite DNA it also seems important in accounting for the evolution of VNTR loci including minisatellites. This conclusion is consistent with the observed nonrandom distributions of VNTRs and other TR-DNAs in the human genome.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=1205220Documentos Relacionados
- Middle repetitive DNA: a fluid component of the Drosophila genome.
- Subunit structure of chromatin and the organization of eukaryotic highly repetitive DNA: Nucleosomal proteins associated with a highly repetitive mammalian DNA
- A transposable element can drive the concerted evolution of tandemly repetitious DNA.
- The evolution of repetitive DNA sequences in sea urchins.
- Does Recombination Shape the Distribution and Evolution of Tandemly Arrayed Genes (TAGs) in the Arabidopsis thaliana Genome?