MadSci Network: Genetics

Re: WHat is genetic vaiation, and what are some evidence that it exsists?

Date: Thu Mar 11 07:19:01 2004
Posted By: Jeremy Cherfas, Staff, Public Awareness, IPGRI (International Plant Genetic Resources Institute)
Area of science: Genetics
ID: 1076366598.Ge

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 

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 

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.


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