Biology in the Laboratory

DNA in the Lab

What is a gene chip?

Yes, DNA can be (and has been) extracted from a mummy. However, the problem with extraction of ancient DNA has to do with contamination from modern DNA. In order to minimize contamination, researchers usually try to get DNA from inside teeth or bone. Ancient DNA is being used to study the genealogy of the pharaohs of Egypt.

A gene chip is part of the process of microarray profiling; it is also known as a biochip or a DNA chip. It is about the size of a postage stamp and is based on a glass wafer, holding as many as 400,000 tiny cells. Each tiny cell can hold DNA from a different human gene and can perform thousands of biological reactions in a few seconds. These chips can be used by pharmaceutical companies to discover what genes are involved in various disease processes. They can also be used to type single nucleotide polymorphisms (SNPs), which are base pair differences that are found approximately every 500 to 1,000 base pairs in DNA. More than three million SNPs are in the human genome. They are very important in DNA typing because they represent about 98 percent of all DNA polymorphisms.


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