SPECIES FOR SALE

Now that you understand the issues related to the international trade in radiated tortoises, its time to use some of your conservation genetics skills in the field. You've just received a call from officials in Germany, where a shipment of tortoises has been confiscated. When you get there you find seven boxes. The problem is, the labels have fallen off of all but one box. Three of the labels on the floor say Madagascar, and the other three say Kenya, Ecuador, and United States. Below are boxes taken from their warehouse.

In the boxes you find seven kinds of tortoises. But what kinds of tortoises are they? The easiest thing would be to look in a field guide and identify them. But, oh no, they are all baby tortoises! This is going to make things difficult, because baby tortoises of different species tend to look alike. You know from the one label that is still attached to a box that the really pretty one with the star pattern on its shell is a radiated tortoise from Madagascar, Geochelone radiata. But what about the other tortoises? There is no way for you to tell which of the other tortoises are from Madagascar, Kenya, Ecuador or the US! And without knowing which is which, you can't do your job and return them to their country of origin.

Don't despair. You have a genetics lab at your disposal (and you happen to be a little bit of an amateur geneticist). If you were to look at the DNA of these tortoises, you would be able to see just how similar or different these tortoises are from one another. Since you know, because you've been reading up on Madagascar's biodiversity, that all the tortoises on Madagascar are closely related to one another, you should be able to find out which three are the closest relatives to the radiated tortoise and from there to figure out where the others are from. As you gather this information, you will construct a cladogram - an evolutionary tree- for these tortoises.

Put on your lab coat and let's head to the GENETICS LAB.