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The activity of a base analog (6-N-hydroxylaminopurine, HAP) has been tested on Aspergillus nidulans. In germinating haploid conidia HAP is a strong mutagen, while it does not have any activity in resting conidia. Moreover, HAP does not increase the frequency of recombination in germinating conidia. The mutagenic activity of this base analog has also been(More)
Pan-American mitochondrial DNA (mtDNA) haplogroup C1 has been recently subdivided into three branches, two of which (C1b and C1c) are characterized by ages and geographical distributions that are indicative of an early arrival from Beringia with Paleo-Indians. In contrast, the estimated ages of C1d--the third subset of C1--looked too young to fit the above(More)
The incompatibility reactions of four new R factors have been determined against reference plasmids of the compatibility groups FI, FII, FIII, FIV, FV, FVI and various not F-like groups. Two R factors have been found to belong to group FII, while one of the two other plasmids was incompatible with representatives of the FII and FI groups. The last R factor(More)
The sequencing of entire human mitochondrial DNAs belonging to haplogroup U reveals that this clade arose shortly after the "out of Africa" exit and rapidly radiated into numerous regionally distinct subclades. Intriguingly, the Saami of Scandinavia and the Berbers of North Africa were found to share an extremely young branch, aged merely approximately(More)
The in vitro mutagenic activity of 5-(3,3-dimethyl-1-triazeno)-imidazole-4-carboxamide (DTIC), has been studied in bacteria and Chinese hamster cells with and without metabolic activation by rat liver microsomes. DTIC was found to be highly mutagenic in the two systems. It is noteworthy that DTIC in the prokaryotic systems did not require metabolic(More)
In order to understand the role of yeast polymerases in spontaneous mutagenesis in non-growing cells we have studied the effects of mutations that impair the 3′→5′ exonuclease function of polymerases delta (pol3-01) and epsilon (pol2-4) on the spontaneous reversion frequency of the frameshift mutation his7-2 in cells starved for histidine. We showed that(More)
Mutagenesis induced in the yeast Saccharomyces cerevisiae by starvation for nutrilites is a well-documented phenomenon of an unknown mechanism. We have previously shown that the polymerase delta proofreading activity controls spontaneous mutagenesis in cells starved for histidine. To obtain further information, we compared the effect of adenine starvation(More)
Haploid and diploid strains of Aspergillus nidulans have been repeatedly treated with the strong mutagen 6-N-hydroxylaminopurine (HAP) which causes only base substitutions. An enormous amount of variability may be rapidly accumulated in haploid or diploid strains of A. nidulans. In particular, in the diploids the analysis of the results shows that after 12(More)
We examined the role of Saccharomyces cerevisiae uracil DNA glycosylase in the suppression of mutagenesis in non-dividing, adenine-starved cells expressing human activation-induced deaminase (AID) gene. Our aim was to further understand the mechanisms preventing starvation-associated mutagenesis in yeast and to explore the consequences of AID gene(More)