To study targeted recombination, a single linear 2-kb fragment of LEU2 DNA was liberated from a chromosomal site within the nucleus of Saccharomyces cerevisiae, by expression of the site-specific HO endonuclease. Gene targeting was scored by gene conversion of a chromosomal leu2 mutant allele by the liberated LEU2 fragment. This occurred at a frequency of only 2 x 10(-4), despite the fact that nearly all cells successfully repaired, by single-strand annealing, the chromosome break created by liberating the fragment. The frequency of Leu+ recombinants was 6- to 25-fold higher in pms1 strains lacking mismatch repair. In 70% of these cases, the colony was sectored for Leu+/Leu-. Similar results were obtained when a 4. 1-kb fragment containing adjacent LEU2 and ADE1 genes was liberated, to convert adjacent leu2 and ade1 mutations on the chromosome. These results suggest that a linear fragment is not assimilated into the recipient chromosome by two crossovers each close to the end of the fragment; rather, heteroduplex DNA between the fragment and the chromosome is apparently formed over the entire region, by the assimilation of one of the two strands of the linear duplex DNA. Moreover, the recovery of Leu+ transformants is frequently defeated by the cell's mismatch repair machinery; more than 85% of mismatches in heteroduplex DNA are corrected in favor of the resident, unbroken (mutant) strand.
This research output has an Altmetric Attention Score of 6. This is our high-level measure of the quality and quantity of online attention that it has received. This Attention Score, as well as the ranking and number of research outputs shown below, was calculated when the research output was last mentioned on 05 January 2011.
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#7,581,585
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Outputs from Proceedings of the National Academy of Sciences of the United States of America
#63,363
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#9,134
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Outputs of similar age from Proceedings of the National Academy of Sciences of the United States of America
#234
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Altmetric has tracked 34,359,530 research outputs across all sources so far. This one has received more attention than most of these and is in the 73rd percentile.
So far Altmetric has tracked 118,929 research outputs from this source. They typically receive a lot more attention than average, with a mean Attention Score of 40.1. This one is in the 37th percentile – i.e., 37% of its peers scored the same or lower than it.
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We're also able to compare this research output to 513 others from the same source and published within six weeks on either side of this one. This one is in the 35th percentile – i.e., 35% of its contemporaries scored the same or lower than it.
