DNA transcription by mRNA. Coloured transmission electron micrograph of DNA & mRNA (messenger RNA) molecules forming a feather-like, transcrip- tionally-active structure. This DNA is from the nucleus of an amphibian egg. The backbone of the feather, running down the image, is a long strand of DNA coated with protein. Numerous mRNA molecules extend in clusters from the DNA strand. Transcription of genetic information begins at one end of the gene, with the mRNA molecules growing longer as they approach completion. Transcription is the first step in protein synthesis. Magnification: x6700 at 6x4.5cm size.