Re: which enzyme should I use to cut human DNA to look for a gene?

To 'cut' DNA, scientists use a class of enzymes known as restriction endonucleases. There are a whole host of these enzymes that can be used to create DNA fragments of varying lengths. Each enzyme recognizes a particular site in the DNA and uses its enzymatic activity to 'clip' the DNA molecule at every site. For example, one of the most common restriction enzyme is derived from the bacteria, E. coli, and is known as EcoR1. EcoR1 recognizes the sequence

5'¦G^AATTC¦3'
3'¦CTTAA^G¦5'

The question you ask is which enzyme you should use to 'cut out' a particular gene, but the answer will depend upon what gene you are interested in isolating. Since I do not know what your gene of interest is, I will give you some resources that will, hopefully, help you choose the best enzyme to accomplish your task.

Your first task will be to choose a gene of interest and to obtain its genetic sequence. There are many good websites that maintain gene databases. My favorite is the NCBI website.

Once you choose a gene, you can copy and paste the genetic sequence into a website called WebCutter . Webcutter is a free online service that will help you map restriction enzyme sites for your gene of interest and tell you what enzymes would be good to use.

I hope that helps you find what you're looking for . . .

Sue Baker, Mad Scientist