Genes for zein subunits on maize chromosome 4

This paper maps nine genes coding for zein subunits on maize chromosome 4. Six of them (Zp6h, Zp10, Zp14, Zp15, Zp22) encode for subunits with a molecular weight of 22 Kd (kilodaltons), while three (Zp27, Zp28, Zp30) code 20-kd subunits. The six 22-kd related genes are not contiguous but are scattered on both chromosome arms, whereas Zp27, Zp28, and Zp30 are more tightly linked in the chromosome short arm in a segment 5 crossover units long. The organization of zein genes on chromosome 4 shows a close analogy with that of zein loci on chromosome 7. This suggests that both maize chromosomes evolved by duplication of short segments.