Localization of cDNAs on wheat genomes by PCR. (i), Amplification with primers ssIIc and ssIIe. (ii), Amplification with primers ssIIc and ssIId. Lanes D, T. tauschii; lanes AB, N7DT7B; lanes AD, N7BT7A; lanes BD, N7AT7B; and lanes ABD, cv Chinese Spring (wild type). PCR products related to each cDNA clone are labeled. The arrow indicates a heteroduplex band that appears only when the A and D genes are amplified in the same mixture (see text).