Variegated Phenotype and Developmental Methylation Changes of a Maize Allele Originating from Epimutation

摘要: Two instances of genetic transmission spontaneous epimutation the maize P-rr gene were identified. Transmission gave rise to two similar, moderately stable alleles, designated P-pr-1 and P-pr-2, that exhibited Mendelian behavior. Both isolates P-pr conditioned a variable variegated phenotype, unlike uniform pigmentation by P-rr. Extensive genomic analysis failed reveal insertions, deletions or restriction site polymorphisms between new allele its progenitor. However, methylation P was increased in relative P-rr, greatly reduced (though not lost) revertant pigmentation. Variability correlated with variability transcript levels gene, both inversely methylation. Part could be accounted for developmental decrease all tissues plants carrying P-pr. We hypothesize phenotype results from general epigenetic pathway which causes progressive increase expression potential as function cell divisions each meristem plant. This renders chimeric functional gene; chimerism is visualized variegation only pericarp due tissue specificity expression. Therefore, this originates may exemplify an mechanism maize.