Completion of the objectives of the Human Genome Initiative will require technical advances which significantly reduce the cost and increase the rate at which sequence information can be obtained. To date, most large scale sequencing efforts have been initiated as random sequencing efforts which have then converted to directed strategies to close gaps in the data. One of the most appealing directed strategies for sequencing is the """"""""primer walking"""""""" method, which utilizes known sequence information to design a distal primer which is then used to obtain additional, downstream sequence information. Primer walking is one of the most efficient ways to obtain sequence information but has not been used extensively because of the time and expense involved in primer synthesis. The new strategy outlined here utilizes 6mer and 8mer oligonucleotide libraries to make 14mer primers through a ligation reaction. Each 14mer can be made by the end user in less than one hour and can be used to generate high quality sequence information. Currently, each primer costs $50 or more. This new methodology has the potential to lower the cost of each primer to less than $0.10. If successful, this method of primer synthesis has the potential to decrease the cost and increase the efficiency with which sequence information is obtained.
