A RAPID AND SIMPLE METHOD OF PRODUCING HIGH-RESOLUTION ZYMOGRAMS FROMBRASSICA AND RELATED SPECIES ON ISOELECTRIC-FOCUSING GELS

Isozymes are potentially valuable genetic markers in the identificatio n of hybrid plants, the assessment of seed purity, and in molecular an d conventional genetic maps. The starch gels commonly used to prepare Brassica zymograms have very low resolutions. Consequently, isoelectri c-focussing polyacrylamide-gel electrophoresis was explored as a means of producing high-resolution zymograms of four Brassica isozymes. Cru de sap extracts were found to be unsuitable for electrophoresis. Centr ifugation, passage over sepharose beads and over night dialysis were t ested as alternative means of clarifying samples. The zymograms presen ted here demonstrate that isoelectric focussing, following overnight s ample dialysis, results in zymograms which, in comparison to their sta rch counterparts, have vastly improved separation and resolution.