Allele Server examines a particularly interesting class of human DNA variations -- the Alu insertion polymorphisms. Alu elements are molecular parasites of retroviruses that have moved about and accumulated in primate genomes over evolutionary time. The human genome contains about 500,000 Alu elements, which represent 5% of the total genome and are a good example of so-called "junk DNA." Most Alu elements inserted in our distant primate past and have become fixed in the human species -- that is, they are invariably present in every person. However, some Alu elements have inserted at chromosome loci within the last one million years, during the development and radiation of the human species. These unfixed mutations are dimorphic -- meaning the Alu insertion may be present or absent at a particular locus.

Allele Server allows you to enter data into our database and examine data already there. It also has several statistical functions: testing Hardy-Weinberg equilibrium within a single population, measuring genetic distance between two populations, or comparing two populations using contingency chi-square. Additional statistical tools will be added over the next several years, including construction of evolutionary trees and maps of allele frequencies.

If you've registered with another DNA Learning Center online project, such as DNA from the Beginning, you can get right to the sequences by logging in with that username and password. You can also create a new account here, or browse the server as a guest.