[PCR walking in cotton genome using YADE method].

A Y-shaped adaptor dependent extension (YADE) method was developed to amplify the unknown genomic sequences adjacent to a known sequence, with the single-primer amplification completely suppressed. Using this method, two fragments, F027S and F027A, adjacent to a cotton ovule cDNA fragment (F027), were amplified using genomic DNA. It was demonstrated that F027S and F027A had 104 bp and 175 bp overlapped to F027, and contained 1 and 3 putative introns, respectively, all of which included conserved border sequence GT-AG and a putative branch site. The possible improvements and applications of YADE method are further discussed.