Surprising discovery leads to new twist on evolution
Fruit fly (drosophila) ovaries showing developing eggs
Photo by Dr. Daniel J. Johnston at Wellcome images
Published this week in the online journal of Science, researchers have discovered a shocking finding that gives a new twist to evolution. Although common in bacteria, it is rare to find the genomes of distantly related organisms, such as bacteria and higher life forms, mix. This is what scientists call “lateral gene transfer”.
However, scientists led by the University of Rochester and the J Craig Venter Institute (remember Venter from another story this week) have found the first cases in which the entire bacterial genome of a parasite (Wolbachia pipientis), was found fully intact in the genome of a higher life form species (fruit fly).
“It didn’t seem possible at first,� says Dr. Jack Werren, team leader at the University of Rochester and a world-leading authority on the parasite, Wolbachia. “This parasite has implanted itself inside the cells of 70 per cent of the world’s invertebrates, coevolving with them. And now, we’ve found at least one species where the parasite’s entire or nearly entire genome has been absorbed and integrated into the host’s. The host’s genes actually hold the coding information for a completely separate species.�
This parasite implants its genes into the sperm and eggs of its host which are passed down in reproduction making the parasitic genes inheritable, which can influence the evolution of the host species. Inheritable genes can also lead to strange mutations during the reproduction process.
W. Ford Doolittle, Canada Research Chair in Comparative Microbial Genomics at Dalhousie University, who is not connected to the study, stated that this “stunning evidence” is like science fiction becoming reality.
Are we unknowingly carrying an entirely different species within our genes that is coevolving with us? And will we eventually see unfathomable mutations? Anyone see that old movie, The Fly? Or is this a natural process through which these bacteria will eventually become assimilated into our bodies like mitochondria and become helpful to the evolution of our species?
Well luckily, this parasite doesn’t exist in humans or other vertebrates, so no need to worry for now. But in the future, scientists will unravel this new mechanism of gene transfer to alleviate some of the inheritable diseases we carry.
Further reading:
- Science article: Widespread Lateral Gene Transfer from Intracellular Bacteria to Multicellular Eukaryotes
- Press release: One species’ entire genome discovered in another
- Technology Review: A Genome within a Genome
Lincoln Kim is a member of the healthcare and life sciences team of the MaRS Venture Group. He evaluates and supports the development of technology platforms and commercial market opportunities of start up and emerging companies, facilitates collaboration among research groups and between research scientists and industry.