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Titolo:
HOW CAN THE LOW-LEVELS OF DNA-SEQUENCE VARIATION IN REGIONS OF THE DROSOPHILA GENOME WITH LOW RECOMBINATION RATES BE EXPLAINED
Autore:
HUDSON RR;
Indirizzi:
UNIV CALIF IRVINE,DEPT ECOL & EVOLUT BIOL IRVINE CA 92717
Titolo Testata:
Proceedings of the National Academy of Sciences of the United Statesof America
fascicolo: 15, volume: 91, anno: 1994,
pagine: 6815 - 6818
SICI:
0027-8424(1994)91:15<6815:HCTLOD>2.0.ZU;2-0
Fonte:
ISI
Lingua:
ENG
Soggetto:
CENTROMERIC REGION; MUTATION-RATE; MELANOGASTER; POLYMORPHISM; POPULATIONS; CHROMOSOME; ANANASSAE; SELECTION;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Science Citation Index Expanded
Citazioni:
25
Recensione:
Indirizzi per estratti:
Citazione:
R.R. Hudson, "HOW CAN THE LOW-LEVELS OF DNA-SEQUENCE VARIATION IN REGIONS OF THE DROSOPHILA GENOME WITH LOW RECOMBINATION RATES BE EXPLAINED", Proceedings of the National Academy of Sciences of the United Statesof America, 91(15), 1994, pp. 6815-6818

Abstract

Different regions of the Drosophila genome have very different rates of recombination. For example, near centromeres and near the tips of chromosomes, the rates of recombination are much lower than in other regions. Several surveys of polymorphisms in Drosophila have now documented that levels of DNA polymorphism are positively correlated with rates of recombination; i.e., regions with low rates of recombination tend to have low levels of DNA polymorphism within populations of Drosophila. Three hypotheses are reviewed that might account for these observations. The first hypothesis is that regions of low recombination havelow neutral mutation rates. Under this hypothesis between-species divergences should also be low in regions of low recombination. In fact, regions of low recombination have diverged at the same rate as other regions of the genome. On this basis, this strictly neutral hypothesis is rejected. The second hypothesis is that the process of fixation of favorable mutations leads to the observed correlation between polymorphism and recombination. This occurs via genetic hitchhiking, in which linked regions of the genome are swept along with the selectively favored mutant as it increases in frequency and eventually fixes in the population. This hitchhiking model with fixation of favorable mutations is compatible with major features of the data. By assuming this model is correct, one can estimate the rate of fixation of favorable mutations. The third hypothesis is that selection against continually arisingdeleterious mutations results in reduced levels of polymorphism at linked loci. Analysis of this background selection model shows that it can produce some reduction in levels of polymorphism but cannot explainsome extreme cases that have been observed. Thus, it appears that hitchhiking of favorable mutations and background selection against deleterious mutations must be considered together to correctly account for the patterns of polymorphism that are observed in Drosophila.

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Documento generato il 02/12/20 alle ore 16:14:12