Implications of double-stranded DNA structure for development, cancer and evolution

Abstract

Genomes consist of DNA and the genetic information is encoded in a linear form of DNA. According to the central dogma of molecular biology, the genetic information is transcribed into mRNA, and mRNA translated into a polypeptide. Gene expression should be precisely regulated in order to create progeny. Unlike RNA, DNA has double-stranded structure. Is there any specific biological reason why DNA has evolved to possess double-stranded structure? In this presentation, biological implications of the double-stranded structure of the DNA molecule will be reviewed. In eukaryotes, it has been reported that cells might have the machinery that distinguishes one DNA-strand from the other, and that the strand-recognition mechanism might control development, cancer and evolution. Three prominent models concerning biological implications of replication of double-stranded DNA will be discussed: 1) Klar's "somatic strand-specific imprinting and selective chromatid segregation model" for differential gene regulation, 2) Cairns' "immor-tal strand inheritance model" for cancer prohibition, and 3) the "disparity mutagenesis model" for the acceleration of evolution proposed by the present author.