SINEs, and other transposable elements, are not normally transcribed by the cell's machinery to produce the molecular messengers by which genes act.
Yet where it matters, transposable elements can be cleared out of the human genome too.
But Dr Nuzhdin reckons that it may hold a clue to the proliferation of different transposable elements in other organisms.
Together with the transposable elements and the fact that significant blocks of DNA will occasionally duplicate themselves and pass down the generations without apparent harm to the creatures containing them, they form a sort of fossil record of a species' past.
And in a few cases those elements have been co-opted by their hosts to even better effect: it looks as though at least 20 genes that play a useful role in the human body originally came from transposable elements.
Chemicals and energy are needed to create DNA, so eliminating these free-riders, known technically as transposable elements, ought to make evolutionary sense.
These are the descendants of ancient infections that have managed to hide away in the genome and get themselves passed from generation to generation along with the rest of the genes.Dr Kelley and Dr Rinn realised that the movement within the genome of transposable elements is a sort of mutation, and wondered if it has evolutionary consequences.
Rather, the number of copies of copia expanded exponentially suggesting that the more copies of copia a fly has, the faster they accumulate.Dr Nuzhdin thinks that the main reason why copia does not proliferate like this in wild populations is that natural selection keeps these transposable elements in check.
Thanks to SINEs, therefore, a stressed cell may be able to respond more rapidly to the threat in question.Similar advantages to the continued existence of other sorts of transposable element will probably turn up when people start looking in detail.
Genomes are not picky about where they acquire useful material, and transposable elements are not the only things to have been plundered.
Their conclusion is that it does, for when they looked at the relation between such elements and lincRNA genes, they found some intriguing patterns.In the first place, lincRNAs are much more likely to contain transposable elements than protein-coding genes are.
