Am I half a banana?

Chris Smith put Sam's question to foodie and geneticist Giles Yeo...

Giles - We clearly share 50 percent of some of the genes with the banana because we're all living beings on Earth and we effectively evolved from the same primordial soup. And so there are going to be enzymatic reactions, things that actually happen with us that are going to be shared. But clearly just sharing the DNA does not make you 50 percent a banana. I mean it's like saying that we share 98 percent of our DNA, complete DNA, with chimpanzees. Does that make us 98 percent chimp? I think what is critical is not only the stuff that is there but how it's turned on and how it's actually turned off. And I think that is probably what is the biggest differences there. So no, I mean we're not 50 percent banana per say even though we share half our genes with the banana.

Chris - Is it really coming down to the distinction of what is a gene? Because a gene is essentially a block of DNA that does a job in a cell and that gene is made of genetic letters, which is how it's spelled out. So I could have a gene in a banana that does a similar job to a gene in a human, but the actual genetic spelling of those two genes, they do a very similar job in the two contexts, but actually they're spelled quite differently. So it's actually down to semantics, what actually is a gene compared between two species.

Giles- That's absolutely right.