•Physical markers are markers exploit polymorphisms in DNA sequences that do not necessarily have a phenotype=. That is, they may be silent mutations.
• Physical markers can occur anywhere in the genome, including introns and intergenic regions.
• Most often rely on differences in the mobility of products in an agarose gel (as a result of differential restriction sites or different size of PCR-amplified products.
• These include RFLPs, CAPs, and SSLPs.