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Name: Sneha
Status: other
Grade: other
Location: Outside U.S.
Country: India
Date: Summer 2012

Why is it so that viruses contain either RNA or DNA? Why they don't contain both?

The simpler a virus is, the more copies can be replicated rapidly. Thus, viruses that have a minimum amount of genes are favored. If a virus can replicate with just one or the other (RNA or DNA), it can have an advantage in reproduction over more complicated viruses. Also, if the virus were to require both types of genes, the odds of something going wrong increases -- and could make the virus unable to replicate.

Hope this helps, Burr

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