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Causes of genetic variation

Genetic variation arises in a population in a number of different ways. Here, David Ackerley of Victoria University, Wellington, explains when genetic variation may arise and how it affects an organism’s DNA.

Genetic variation can arise from random mistakes made when the DNA is being reproduced. Environmental factors, such as exposure to toxins, can influence the number of changes to the DNA sequence.

Transcript

David Ackerley (Victoria University, Wellington): Genetic variation in a population of plants or animals or organisms can arise in a number of ways.

At the whole organism level, what’s happening is you are getting this variation which arises just through random mistakes in that organism copying its DNA, or it gets promoted by things like environmental toxins, or smoking is a factor that contributes to heightened rates of mutation, and that’s actually going to alter the DNA of a particular cell.

It basically comes down to changes in the sequence of your DNA. And this can be things like deletions, it can be extra bits of DNA popping there, or just changes in the bases that are there, so from a G [guanosine] to a C [cysteine], or things like that.

And what happens is, when you get those changes in your genes, that translates into a change in the sequence of the protein that is encoded by that gene. So it’s kind of like if you translated a sentence into code and then you randomly swapped a few letters and then translated it back you wouldn't have the same message that you started with.

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