Organization of paramutagenicity in R-stippled maize

• Published in: Genetics (Austin) 1995-09, Vol.141 (1), p.361-372
• Main Authors: Kermicle, J. L, Eggleston, W. B, Alleman, M
• Format: Article
• Language: English
• Subjects: adn; amande de la graine; binding proteins; Biochemistry; color; colour; Corn; couleur; crossing over; Crossing Over, Genetic; cruzamiento intercromosomico; dna; fenotipos; gene; Gene Deletion; genes; Genes, Plant; Genetic Complementation Test; genetica; Genetics; genetique; germen; Investigations; kernels; mutacion; Mutagenesis; mutagenicidad; mutagenicite; mutagenicity; Mutation; phenotype; phenotypes; pigmentacion; pigmentation; Pigmentation - genetics; Plant Leaves; proteinas aglutinantes; proteine de liaison; recombinacion; recombinaison; recombination; zea mays; Zea mays - genetics
• ISSN: 0016-6731; 1943-2631; 1943-2631
• DOI: 10.1093/genetics/141.1.361

In heterozygotes, R-stippled (R-st) reduces the pigmenting potential of sensitive r alleles heritably (paramutation). R-st is comprised of four r genes arranged in direct orientation. Unequal crossing over within R-st generates deletion products retaining from one to three r genes. Paramutagenic strength decreased in parallel with copy number, both among internal and distal deletions. Single-gene R-st derivatives were nonparamutagenic. This was so whether or not the single gene retained the transposable element (I-R) responsible for seed spotting. Adding back r genes by intragenic recombination increased paramutagenicity in proportion to total gene number. Each member of a set of overlapping deletions retained moderately strong activity, showing that no single r gene or intragenic region is required for paramutagenicity. Proximal and distal loss Rest derivatives, each retaining two r genes, were less paramutagenic in bans than the corresponding four copy cis combination, indicating R-st's paramutagenic determinants function as a cis-interdependent unit in bringing about modification of a sensitive allele.