小RNA（sRNA）是真核基因和转座因子（TE）的表观遗传调节因子。物种中存在不同的sRNA表达模式，但是这种多样性是如何产生的还没有得到很好的理解。为了提供玉米sRNA模式动态的窗口，在两个相关的玉米重组自交系（RIL）及其近交亲本中检查了sRNA和mRNA转录组。这些RIL的分析揭示,大多数sRNA表达簇保留亲本sRNA表达水平。然而,还观察到与亲本等位基因不同的表达状态，主要反映了sRNA表达的减少。当RILsRNA表达不同于亲本等位基因时，两个RIL之间的新状态通常相似，并且类似于在另一个亲本中的等位基因处发现的表达状态。新型sRNA表达模式，不同于父母双方的，是罕见的。此外,TEs上的sRNA表达检查显示一个TE家族，Gyma,与亲本等位基因中发现的那些相比，RILsRNA表达差异显示出一致的富集。这些发现提供了关于sRNA沉默如何在几代人中进化的见解，并表明需要进一步研究sRNA反式调节因子的分子性质。
Small RNAs (sRNAs) are epigenetic regulators of eukaryotic genes and transposable elements (TEs). Diverse sRNA expression patterns exist within a species, but how this diversity arises is not well understood. To provide a window into the dynamics of maize sRNA patterning, sRNA and mRNA transcriptomes were examined in two related Zea mays recombinant inbred lines (RILs) and their inbred parents. Analysis of these RILs revealed that most clusters of sRNA expression retained the parental sRNA expression level. However, expression states that differ from the parental allele were also observed, predominantly reflecting decreases in sRNA expression. When RIL sRNA expression differed from the parental allele, the new state was frequently similar between the two RILs, and similar to the expression state found at the allele in the other parent. Novel sRNA expression patterns, distinct from those of either parent, were rare. Additionally, examination of sRNA expression over TEs revealed one TE family, Gyma, which showed consistent enrichment for RIL sRNA expression differences compared to those found in parental alleles. These findings provide insights into how sRNA silencing might evolve over generations and suggest that further investigation into the molecular nature of sRNA trans regulators is warranted.
