Types of DNA Chips and Their Production
Following two types of DNA chips are generally available
(i) Oligonucleotide-based chips, which contain high density of short oligonucleotides of known sequences, generally 20 to 25 nucleotides long (100,000 to 400,000 oligonucleotides immobilized within an area of 1.6 cm2).
(ii) eDNA-based chips, which contain a high density of cDNA samples, sometimes derived as PCR amplified DNA fragments. While the former are often used for sequencing by hybridization (SBH) for detection of SNPs, etc., the latter are often used for studying gene expression patterns in time and space (for SNPs, consult).
