More than 100 scientists from Australia, Asia, Europe and the US have been probing the genome of the mouse in a joint study lasting several years. Their results in some aspects have completely overturned geneticists' traditional assumptions. The findings are available in the prestigious journal Science on 2nd September. The general conclusion of the study is that the genome of mammals is much more complex than was hitherto supposed.
The genetic material of mammals, the DNA, can be compared to an enormous encyclopedia containing the complete blueprint of the animal in question. Yet this comparison is misleading: over the past few years it has been realised that on most pages of the encyclopedia there is no information at all: they contain a chaotic sequence of letters. Mixed in among these pages there are intelligible pages from time to time, the genes.
The DNA encyclopedia is stored in the nuclei of the cells. If the body is to produce a specific protein, the appropriate page of the encyclopedia is copied (rewritten or 'transcribed'). Only the copies can leave the cell nucleus. They consist of a DNA-like material known as mRNA. Each mRNA contains the blueprint for precisely one specific protein ?this at least has been the traditional doctrine.
Three years ago the DNA of the mouse was completely sequenced. An international research team consisting of more than 100 scientists has been attempting since then to isolate and analyse the entire mRNA transcripts in the mouse. Their most astonishing finding is that more than 60 per cent of all mRNAs are not protein blueprints at all. 'We don't know what the function of these RNAs is,' the Bonn neurobiologist Professor Andreas Zimmer admits. However, they seem to be extremely important: even in such different organisms as hens and mice these ostensibly so unimportant RNAs are very similar. If they really had no function they would hav
Source:University of Bonn