Linked Linear Amplification: A New Method for the Amplification of DNA

new nucleic acid amplification method that uses multi-ple cycles of primer extension reactions. The presence of nonreplicable elements in LLA primers renders primer extension products unusable as templates for further amplification, leading to linear accumulation of prod-ucts. Through the use of nested primers, linear reactions can be “linked”, providing total amplification yields comparable to those obtained by PCR. Methods: The LLA model predicts (a) that amplification yield will approach that of PCR as the number of primers increases and (b) that the unique composition of LLA products will give lower carryover amplification efficiency compared with PCR. To test these hypothe-ses, the human b-globin gene was amplified by 10-, 14-, or 18-primer LLA and the yield was compared with PCR