Recently, a few people (Saroj Mohapatra, Ernest Turro and Bao Cao) have wondered why there appear to be more probes in the hgu95acdf environment than in the hgu95aprobe package. This is also true of the hgu95av2cdf/hgu95av2probe packages as well, and appears to be due to the fact that 172 of the probesets on these chips were based on TIGR annotations. If you were to search netaffx for any one of them, there won't be any sequence information there, just the statement "Contact The Institute for Genomic Research for sequence and details". Unfortunately, the link they give to tigr is busted, but I am sure those interested could be able to wrest the information they desire from the Dana Farber website that you get directed to. Anyway, I would imagine that there are some patent issues that keep Affy from being able to redistribute the sequences, which is why they don't appear in the probe sequence files, nor on netaffx. Best, Jim -- James W. MacDonald, M.S. Biostatistician Affymetrix and cDNA Microarray Core University of Michigan Cancer Center 1500 E. Medical Center Drive 7410 CCGC Ann Arbor MI 48109 734-647-5623 ********************************************************** Electronic Mail is not secure, may not be read every day, and should not be used for urgent or sensitive issues.