Abstract: The present disclosure provides a DNA plasmid comprising a sequence which encodes an mRNA molecule and a modified poly(A) tail, wherein the part of the sequence that encodes the modified poly(A) tail is characterized in that it consists of at least two A elements each defined as a nucleotide sequence consisting of 55 to 65 T nucleotides and at least one S element each S element consisting of one nucleotide that is not a T nucleotide, or 2 to 10 nucleotides, preferably 6 nucleotides, wherein each of the two terminal nucleotides is not a T nucleotide, wherein the number of A elements is one more than the number of S elements, and wherein any two A elements are separated by one S element; said DNA plasmid exhibiting a reduced recombination during amplification in a bacterial host cell compared to the same DNA plasmid without said at least one S element.