ALFRED Site graphing information
      The ALlele FREquency Database   
ALFRED is a resource of gene frequency data on human populations
supported by the Yale Center for Medical Informatics.

The allele (or haplotype) graphing tool currently dynamically generates a histogram of allele frequencies at a site using the same data that can be gathered with a search from within ALFRED and displayed as a numeric table. The length of the colored bar represents the allele frequency; the correspondence between alleles (or haplotypes) and colors is given at the bottom of the page. Populations are sorted by rough geographic region. Populations within geographic regions are sorted alphabetically by name.

In some cases, the histogram bar for a site may not be the same length as other sites. This is due to a rounding error. In the extreme case where the sum of allele frequencies is less than 0.99 or greater than 1.01, a note to that effect appears to the right of the histogram bar for that population and the administrator of ALFRED is notified.

For multiallelic genetics systems such as STRPs and haplotypes, the histogram displays the 10 most frequent alleles, on average, across the population samples summarized. The remaining alleles are grouped together into a residual class and the residual class frequency is displayed as a gray bar.

© 2019 Kenneth K Kidd, Yale University. All rights reserved. The full Copyright Notification is also available.
Originally prototyped by Michael Osier with the aid of Kei Cheung
Upgrades and maintenance since 2002 by Haseena Rajeevan