Date:

Monday, April 8, 2002

Speaker:

Dr. William Eddy

Affiliation:

Statistics Department
Carnegie Mellon University

Contact Information

bill@stat.cmu.edu

Title:

Systematic Variation in Genetic Microarray Data

Abstract:

Current genetic microarray technology allows estimation of differential expression rates for ten thousand or more genes simultaneously. A chip (the microarray) is manufactured by a robotic arraying device which dips capillary pins into wells and places spots from the pins on the glass chip. Later, the two test samples are separately dyed with flourescent dyes, mixed, and combined with the cDNA on the chip in a competitive hybridization reaction. The chip is than scanned in a dual frequency laser scanner and numbers are assigned to each of the spots in all the pairs by complex image processing software. There are many sources of error, both systematic and random. Here we will show the importance of systematic variation in deciding which genes are differentially expressed. The levels of expression change and the particular genes expressed change when the systematic variation is accounted for.