2005 Annual Report 4d.Progress report. This report serves to document research conducted under a specific cooperative agreement between ARS and the Department of Agronomy, Purdue University and is a subcontract derived from a grant from the United Soybean Board (#4239) and supports the objectives of project 1275-21000-164-00D. Additional details of the research can be found in the report for the parent project 1275-21000-164-00D (A Single Nucleotide Polymorphism-based Map of Soybean and Applications to Gene Discovery in Germplasm). The objectives of this agreement are to develop and employ an overgo (OVERlapping oliGOnucleotides) hybridization system for the identification of soybean bacterial artificial chromosome (BAC) clones that contain specific DNA sequences. The DNA sequences to be used in the design of the overgo hybridization probes will be derived from DNA markers that have been positioned on the genetic map of soybean or that will be positioned in the near future. Nearly 1000 overgo hybridizations to two soybean BAC libraries were successfully completed during the reporting period. The BAC clones identified by the overgo probes will be important in anchoring the soybean physical map to the genetic map.