The cer-cqu region in barley: Gene cluster or multifunctional gene

Abstract

Among the eceriferum loci cer-c,-q and -u control three different steps in the pathway leading to β-diketones, hydroxy-β-diketones and esterified alkan-2-ols. Chemical analyses of the wax on spikes of wild type and representative single and apparent multiple mutants demonstrated that such mutants do not affect the composition of the other wax lipids and confirmed the earlier deduced sites of action of cer-c,-q and -u. Each pair of the three markers cer-c3,-q35 and -u58 was found by test cross analysis to be closer together than 0.025 map units. This deduction was derived from the failure of the markers to recombine in the 26,933 gametes tested. The obtained results are expected 95% of the time if the actual distance between any pair is approximately 0.0012 map units. The linear sequence of the three markers could not be determined. The combined results lead to the suggestion that the cer-cqu region is more likely to represent a multifunctional gene than a gene cluster. © 1980 Carlsberg Laboratory.