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Dispersed repetitive DNA sequences from yeast (Saccharomyces cerevisiae) nuclear DNA have been isolated as molecular hybrids in lambdagt. Related S. cerevisiae strains show marked alterations in the size of the restriction fragments containing these repetitive DNAs. "Ty1" is one such family of repeated sequences in yeast and consists of a 5.6 kilobase (kb)(More)
Plasmid DNAs from six strains of Saccharomyces cerevisiae were compared. Three different plasmids were found, designated Scp 1, Scp 2 and Scp 3, with monomer lengths of 6.19, 6.06 and 5.97 kilobases as referenced to sequenced phiX174 DNA. DNA from each of the plasmids was inserted into a lambda vector DNA. Hybrid phage containing inserted DNA of the desired(More)
People in some areas of Ramsar, a city in northern Iran, receive an annual radiation absorbed dose from background radiation that is up to 260 mSv y(-1), substantially higher than the 20 mSv y(-1) that is permitted for radiation workers. Inhabitants of Ramsar have lived for many generations in these high background areas. Cytogenetic studies show no(More)
A bacteriophage lambda strain has been constructed and a method developed by which DNA from potentially any source can be covalently inserted through EcoRI cohesive ends into the middle of the lambda DNA. These hybrid DNAs can infect nonrestricting Escherichia coli cells and can then propagate as plaque-forming phage. A unique feature of this lambda strain(More)
DNA from lambdagt-lambdaB bacteriophage was cleaved with EcoRI endonuclease and fragments from EcoRI-digested E. coli DNA were inserted. This DNA was used to infect E. coli, and phages containing the gene for DNA ligase were isolated by genetic selection. Two different hybrids were found with the same E. coli segment inserted in opposite orientations. Both(More)
A lambda vector that contains the gene for Escherichia coli DNA ligase (lambdagt4-lop-11 lig+) has been modified to achieve overproduction of this enzyme. The third Eco RI site in the lambda chromosome has been altered by mutation, and the left-hand Eco RI fragment has been shortened. The new vector, lambdagt4-lop-11 lig+, forms a stable lysogen which, upon(More)