Transposable elements as mutator genes in evolution

摘要: Strains of the bacterium Escherichia coli habouring genes that increase mutation rates are known to have an evolutionary advantage in chemostat competition over otherwise isogeneic strains with lower rates1–3. This is frequency-dependent, mutator strain being favoured only above a starting ratio ∼5×10−5, and it results from fact necessary beneficial mutations cannot be generated population below certain size3. Here we consider possibility mutagenic4,5 properties transposable elements confer same manner as genes. A previous report has shown transposon Tn5 increases fitness E. chemostats, although reason for this effect not been established6. Our show Tn10 also confers chemostats. In addition, find (1) advantage, like associated genes, (2) whenever win, segment Tn10, probably its IS10 sequences, undergone transposition new site, (3) insertions converge into site contained within 3.2 kilobase (kb) PvuII fragment genome, (4) no transpositions detected when lses. We conclude by increasing rate host bacterium.