DNA methylation in diploid inbred lines of potatoes and its possible role in the regulation of heterosis.
Self-incompatible diploid potatoes were altered to self-compatible ones by a function of S-locus inhibitor gene and continued selfing generated highly homozygous inbreds. In this study, this process was investigated for the status of DNA methylation by a simple method using genomic DNA digested by methylation-sensitive restriction enzymes prior to RAPD analysis. We detected 31 methylation-sensitive RAPD bands, of which 11 were newly appeared in the selfed progenies, and 6 of them stably inherited to subsequent generations. Aberrant segregations and paternal- or atavism-like transmission were also found. Segregating methylation-sensitive bands in initial populations became fixed in the advanced selfed progenies by 75.0-93.8%, of which 41.7% were fixed to all present and 58.3% to all absent. Because DNA methylation is generally recognized to suppress gene expression as regulatory factors, homozygosity/heterozygosity of methylated DNA may be involved in inbreeding depression/heterosis.
Nakamura
Sunao
S
Food Resources Education and Research Center, Kobe University, 1348 Uzurano, Kasai, Hyogo 675-2103, Japan.
Hosaka
Kazuyoshi
K
D019175:DNA Methylation; D004171:Diploidy; D017343:Genes, Plant; D006823:Hybrid Vigor / Q000235:genetics*; D007178:Inbreeding; D019105:Random Amplified Polymorphic DNA Technique; D011198:Solanum tuberosum / Q000235:genetics* / Q000254:growth & development