Validation of Kir isoform typing with reporter enzyme ScrF I. Degenerate PCR with sub-family centred primers was performed on Kir subclone templates and products were T4 DNA polymerase end-labelled according to Materials and Methods. Diagnostic restriction digests were performed using ScrF I and an isoform specific duplex banding pattern generated consistent with the predicted banding patterns described in Figure 1. Faint low MW fragments (<50 bp) are indicated with an arrowhead. One Kir isoform from each sub-family is shown. The predicted fragment sizes based on sequence analysis for each isoform are indicated (bp). Gel image was scanned and processed using Adobe Photoshop Version 5.5.