Foreign pieces of DNA are found in the genomes of many animals – these ‘Genomic parasites‘ are pure, genome hopping pieces of DNA code which embed their lifecycle within the DNA in our own cells. You could call this genomic parasitisation a form of genetic modification, just as scientists in labs the world over use simple molecular biology techniques to insert useful genes into genomes to better understand biological processes. However, most of the time, genomic parasites like transposons have no function in their hosts and simply hitch along for the ride, reproducing as the host reproduces. This doesn’t fit our usual understanding of the meaning of genetic modification, which involves humans and active manipulation of the genome, in most cases to improve it.
Genomic parasites – we all have them but how are they kept under control?
You may think you are parasite free. “No malaria, bilharzia or tapeworms in me”, I hear you say… If you think this you’re actually mistaken. Humans, and many organisms besides, carry parasites within their own DNA. These parasites have left behind the ‘traditional’ parasitic life cycle, with their own body or their own cell living within us and have gone purist, trimming everything away and simply copying their genome into ours, existing alongside us for as long as humans survive. Known as transposons, these genomic parasites use our own cells to survive, using our own machinery to copy themselves, replicating and surviving just as organisms endeavour to do on the land, in the air or in the sea. They could copy themselves all over our genome making even more copies of themselves but something prevents this, stopping the transposon from overwhelming our genome and killing us. Research from the University of Cambridge, the University of Nottingham, and the Fred Hutchinson Cancer Centre in Seattle reveals why: Continue reading “Genomic parasites”