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.