Are you different from your dinner?

As Christmas dinner looms for those celebrating, are you any different from it? Well on the face of it the answer would seem obvious. Of course you are! Apart from anything else, if you were eating a dinner that was the same as you, that would make you a cannibal. In most cultures this is unacceptable. Not to mention unpalatable. So the answer is: “Yes I am.” End of story. Case closed.

alignmentBut is it? As with any good newspaper or magazine headline, it depends on which angle you are reporting on. The angle here, as you have no doubt already worked out is the Dinky Amigos – or DNA – of your dinner. Even looking at such a sub-cellular level, you were right the first time. You are different to your dinner (you are even different to your close family and they look and act a lot more like you than a root vegetable does). But maybe you are not as different as you think.

Humans share about 60% identity with most of their dinner. Identity is measured in exactly how many and in which order the Dinky Amigos line up in the DNA of each species. Be that Homo sapiens (human), Meleagris gallopavo (turkey), Solanum tuberosum (potato) or Brassica oleracea var. gemmifera (Brussels sprout). Well over half and nearly two thirds of you would seem identical to the dinner you are eating.

That seems rather unfair. Are humans really so close to a number of other apparently unrelated species? They are, but not necessarily in the way you might imagine. The chances of your mother revealing that your father is, in fact, a plant is unlikely. Instead this identity concentrates on the functions that are crucial to all living things. DNA replication, energy production or general quality control within the cell for example. Comparison of Dinky Amigo sequences involved in processes such as limb formation, facial expression or vocal attribution will not produce similar results.   



So next time someone tells you that people share 50% of their DNA with a banana, you can carry on happily munching, safe in the knowledge that it is an improbable description of your specifically human qualities.