Evolution of anthocyanin biosynthesis in maize kernels: the role of regulatory and enzymatic loci

• Published in: Genetics (Austin) Vol. 143; no. 3; pp. 1395 - 1407
• Main Authors: Hanson, M.A. (Elmira College, Elmira, NY.), Gaut, B.S, Stec, A.O, Fuerstenberg, S.I, Goodman, M.M, Coe, E.H, Doebley, J.F
• Format: Journal Article
• Language: English
• Published: United States Genetics Soc America 01-07-1996; Genetics Society of America
• Subjects: ADN; Alleles; AMANDE DE LA GRAINE; ANTHOCYANE; Anthocyanins - biosynthesis; ANTOCIANINAS; BIOSINTESIS; BIOSYNTHESE; Chromosome Mapping; Corn; ENZIMAS; ENZYME; Enzymes; Enzymes - genetics; Evolution; Evolution, Molecular; FILOGENIA; GENE; GENES; Genetic Variation; Genetics; GENOTIPOS; GENOTYPE; GERMEN; INTROGRESION; INTROGRESSION; Investigations; LOCI; LOCUS; PHYLOGENIE; Phylogeny; Plant Proteins - genetics; POLIMORFISMO GENETICO; POLYMORPHISME GENETIQUE; Promoter Regions, Genetic; PROTEINAS AGLUTINANTES; PROTEINE DE LIAISON; Recombination, Genetic; Regulatory Sequences, Nucleic Acid; SECUENCIA NUCLEOTIDICA; SEQUENCE NUCLEOTIDIQUE; ZEA; ZEA DIPLOPERENNIS; ZEA MAYS; Zea mays - genetics
• ISSN: 0016-6731; 1943-2631; 1943-2631
• DOI: 10.1093/genetics/143.3.1395

Understanding which genes contribute to evolutionary change and the nature of the alterations in them are fundamental challenges in evolution. We analyzed regulatory and enzymatic genes in the maize anthocyanin pathway as related to the evolution of anthocyanin-pigmented kernels in maize from colorless kernels of its progenitor, teosinte. Genetic tests indicate that teosinte possesses functional alleles at all enzymatic loci. At two regulatory loci, most teosintes possess alleles that encode functional proteins, but ones that are not expressed during kernel development and not capable of activating anthocyanin biosynthesis there. We investigated nucleotide polymorphism at one of the regulatory loci, c1. Several observations suggest that c1 has not evolved in a strictly neutral manner, including an exceptionally low level of polymorphism and a biased representation of haplotypes in maize. Curiously, sequence data show that most of our teosinte samples possess a promoter element necessary for the activation of the anthocyanin pathway during kernel development, although genetic tests indicate that teosinte c1 alleles are not active during kernel development. Our analyses suggest that the evolution of the purple kernels resulted from changes in cis regulatory elements at regulatory loci and not changes in either regulatory protein function nor the enzymatic loci