Epigenetic variation through the breeding processes of maize

The concurrent epigenetic changes during this period of remarkable improvement in maize grain yield remain unknown. Here, we performed MethylC-seq and RNA-seq on 4 related inbred lines with known pedigree information. Analysis of epigenetic changes over the course of historical maize breeding is a valuable new avenue in the exploration for crop improvement. These data lead us to suggest that novel epihaplotypes, in addition to DNA variation, are a substrate of selection during breeding, and that epigenetic variation between parents may also contribute to heterosis in hybrids.

玉米籽粒产量显著提升阶段伴随发生的表观遗传变化，目前仍未被探明。本研究针对4个具有已知系谱信息的相关近交系，开展了甲基化测序（MethylC-seq）与转录组测序（RNA-seq）实验。针对历史玉米育种进程中表观遗传变化的分析，是探索作物遗传改良的一条极具价值的全新途径。基于上述实验数据，我们提出：除DNA序列变异外，新型表观单倍型（epihaplotype）亦是育种过程中人工选择的作用底物；同时，亲本间的表观遗传变异或许也可对杂交种的杂种优势形成产生贡献。