Commonwealth Scientific and Industrial Research Organization Plant Industry, Canberra, Australian Capital Territory 2601, Australia.
Proc Natl Acad Sci U S A. 2011 Feb 8;108(6):2617-22. doi: 10.1073/pnas.1019217108. Epub 2011 Jan 25.
Intraspecific hybrids between the Arabidopsis thaliana accessions C24 and Landsberg erecta have strong heterosis. The reciprocal hybrids show a decreased level of 24-nt small RNA (sRNA) relative to the parents with the decrease greatest for those loci where the parents had markedly different 24-nt sRNA levels. The genomic regions with reduced 24-nt sRNA levels were largely associated with genes and their flanking regions indicating a potential effect on gene expression. We identified several examples of genes with altered 24-nt sRNA levels that showed correlated changes in DNA methylation and expression levels. We suggest that such epigenetically generated differences in gene activity may contribute to hybrid vigor and that the epigenetic diversity between ecotypes provides increased allelic (epi-allelic) variability that could contribute to heterosis.
拟南芥 C24 和 Landsberg erecta 品系的种内杂种具有很强的杂种优势。与亲本相比，正反交杂种的 24 核苷酸小 RNA（sRNA）水平降低，其中父母本 24 核苷酸 sRNA 水平差异最大的那些基因座降低最多。24-nt sRNA 水平降低的基因组区域主要与基因及其侧翼区域相关，表明可能对基因表达有影响。我们鉴定了几个具有改变的 24-nt sRNA 水平的基因的例子，这些基因的 DNA 甲基化和表达水平发生了相关变化。我们认为，这种基因活性的表观遗传差异可能有助于杂种优势，而生态型之间的表观遗传多样性提供了增加的等位基因（表观等位基因）变异性，这可能有助于杂种优势。
