We had already cloned the RAD55 gene of 4.3 kb size from the gene library of Saccharomyces cerevisiae in 1985, and further analysed the cloned gene. Restriction enzyme analysis revealed that the cloned DNA fragment has one of each Pst I, Hinc II, Xba I, Hpa I, and two of each Bg1 II, EcoRI, Xho I, Xmn I, Ssp I, sites. The cloned RAD55 gene did neither suppress the Ocher and Amber mutants, nor hybridize with yeast tRNA probes, suggesting that our cloned gene is not a suppressor gene. It was also detected by Northern blot that the cloned gene was transcribed into mRNA of which size is 1.8kb. The cloned gene did not complement rad52 and rad3 epistasis group mutants, indicating that RAD55 gene has its intrinsic characteristics in recombinational repair pathways of Saccharomyces cerevisiae.