DNA hybridization to mismatched templates: a chip study.
High-density oligonucleotide arrays are among the most rapidly expanding technologies in biology today. In the GeneChip system, the reconstruction of the sample mRNA concentrations depends upon the differential signal generated by hybridizing the RNA to two nearly identical templates: a perfect match probe (PM) containing the exact biological sequence; and a single mismatch (MM) differing from the PM by a single base substitution. It has been observed that a large fraction of MMs repetitively bind targets better than the PMs, against the obvious expectation of sequence specificity. We examine this problem via statistical analysis of a large set of microarray experiments. We classify the probes according to their signal to noise (S/N) ratio, defined as the eccentricity of a (PM,MM) pair's "trajectory" across many experiments. Of those probes having large S/N (>3) only a fraction behave consistently with the commonly assumed hybridization model. Our results imply that the physics of DNA hybridization in microarrays is more complex than expected, and suggest estimators for the target RNA concentration.
Naef
Felix
F
Center for Studies in Physics and Biology, Rockefeller University, 1230 York Avenue, New York, New York 10021, USA.
Lim
Daniel A
DA
Patil
Nila
N
Magnasco
Marcelo
M
D000818:Animals; D020137:Base Pair Mismatch / Q000235:genetics*; D001921:Brain / Q000166:cytology; D002457:Cell Extracts / Q000235:genetics; D015342:DNA Probes / Q000097:blood / Q000145:classification / Q000235:genetics*; D006801:Humans; D051379:Mice; D008957:Models, Genetic; D009693:Nucleic Acid Hybridization / Q000379:methods; D020411:Oligonucleotide Array Sequence Analysis / Q000379:methods* / Q000706:statistics & numerical data; D012333:RNA, Messenger / Q000097:blood / Q000235:genetics / Q000378:metabolism; D013698:Templates, Genetic
D002457:Cell Extracts; D015342:DNA Probes; D012333:RNA, Messenger