Sweet potatoes are naturally transgenic

I'm traveling this week, but I can get at least one blog in.  I hope this one is enlightening. 

We talked about Agrobacterium and how it is a very common tool scientists use  to transfer genes of interest into a target crop's genome.  In the wild Agrobacterium infects some species and causes the disease crown gall.  Infected plants in essence develop a tumor like growth.  Agrobacterium is a somewhat unique bacteria in that it infects its host by incorporating a special piece of DNA called T-DNA  into the hosts's genome.  Normally Agrobacterium is like any other disease in that it infects a plant or a certain number of plants in an area and that is the extent of it's influence.  However what if that T-DNA was incorporated and then the effects of the bacterial T-DNA were selected and carried on in future iterations of a plant species.  This is what researchers have found happened with sweet potatoes.

Sweet potato remains have been in Peru from 8000 - 10000 years ago.  It is one of the oldest domesticated crops.  During the times of domestication there is evidence that some Agrobacterium must have infected some sweet potato plants and those genes from the Agrobacterium T-DNA were incorporated into the genome.  Instead of that special plant dying, its line must have continued to be propagated so that those T-DNA genes stayed in the genome.  Scientists have found those genes still present today.

There is so much hype about how GMOs are bad and unnatural.  Yet Agrobacterium and nature introduced a foreign gene to sweet potatoes thousands of years ago.   If you eat sweet potatoes you may be eating a GMO that was engineered by nature and not scientists.   It is a transgenic world.

Full paper:  http://www.pnas.org/content/112/18/5844.full