Re: Give a Human DNA stran, how many different combinations can you have?

Hi John!

The human genome is made up of about 3,000,000,000 nucleotides each of which can be any of the following: adenine, cytosine, guanine, and thymine. So there are 4 ^ 3,000,000,000 (that's 4 to the 3 billionth power) combinations. However, that's a very naieve model of how many different combinations are allowable by nature.

There are anywhere between 50,000 - 100,000 genes within the human genome, and most genes have a number of different alleles (or "gene states"). Scientists are struggling to understand how different gene and allele combinations are possible, and what the different combinations "mean". No one knows how many of the millions of combinations are viable.

There are a number of internet resources that might shed more light on your question:

You might try looking at the Department of Energy's Primer on Molecular Genetics.

Other resources include the Human Genome Project Information Page.

The National Human Genome Research Instititue

And the *very excellent* Biology Project at Arizona.

The Glossary of Molecular Biology

The Glossary of Basic Genetic Terms

There are a number of on-line courses you can look into, including:MedS 514 at Montana (Instructor: Martin Teintze)

I hope this helps, feel free to e-mail me if you need more detail or have any other additional questions!

Sincerely,

Andreas Matern

http:// www.people.cornell.edu/pages/alm13