|MadSci Network: Genetics|
Dear Jenna Genetic variation can be defined in all sorts of different ways, but perhaps the simplest is that it is the variability between individuals that can be inherited directly from one's parents. So, for example, two people may be of different height, one tall and one short. Some of that will be the result of nutrition. If one does not get enough food as a child, that person will not be as tall as if they did get enough food. But some is inherited, genetic variation. The child of two tall parents will almost certainly be taller than the child of two short parents even if they both have the same sort of diet when they are growing up. This is a link to some teaching material that will help you to explore human genetic variation. In general, the kind of evidence one needs to demonstrate genetic variation is of two kinds. One can look directly at the DNA of two individuals and compare their genetic code. That will show up differences. But it will not necessarily tell you whether those differences are important or what they mean. The other approach is to study the results of breeding, either experiments, with plants and animals, or human families. Then one can see whether the differences between individuals are inherited from their parents or whether they are the result of differences in the environment. But do not think that there are purely environmental differences or purely genetic differences. The two always interact with one another to a greater or lesser extent. Jeremy
Try the links in the MadSci Library for more information on Genetics.