Parasitic Plants Actually Steal Genes From the Hosts
by Alasdair Wilkins
The Malaysian plant Rafflesia cantleyi is a parasite, attaching itself to another plant and deriving all its food from its unfortunate host. But Rafflesia doesn’t stop there. It swipes genes from its host, sometimes actually completely replace its old genes.
All of us take part in gene sharing - we all get genes from our parents, and many then pass on genes to their kids. It’s a process called vertical gene transfer since it happens during reproduction from one generation to the next. Horizontal gene transfer happens when two different organisms swap genetic information - the best-known example is when bacteria share their resistance to antibiotics between each other.
While most horizontal gene transfer is the domain of microscopic species, some larger organisms are capable of this trick as well. In the case of Rafflesia, individual organisms have used their lifelong linkups to their hosts - which are, somewhat confusingly, named Tetrastigma rafflee - to upgrade their genes. These aren’t minor changes - some of the plants have stolen the genes for such fundamental processes as respiration and metabolism from the host, then thrown it away. They now quite literally wouldn’t be able to live without their plundered genetics.