Allopolyploidy in the Wintergreen Group of tribe Gaultherieae (Ericaceae) inferred from low-copy nuclear genes

DNA sequence data from the low-copy nuclear genes waxy (GBSSI) and leafy were compared with plastid sequence data from prior studies to reconstruct phylogenetic relationships in the Wintergreen Group of tribe Gaultherieae (Ericaceae). We conducted phylogenetic analysis with 109 species that includes representatives of all 15 major clades previously diagnosed in the Wintergreen Group and that together span its circum-Pacific distribution. Results yielded two distinct homeologous copies of waxy for two of the clades, each in widely separated parts of the tree. It also yielded two copies of leafy for one of the clades; only one copy of leafy was found for the other clade, but it was placed in the same major clade as its waxy counterpart and well away from its placement in a prior plastid analysis. A combined four-locus (waxy, leafy, ITS, and plastid loci) phylogenetic analysis of all available relevant data placed the copies of each of the clades in two distinct positions in the phylogeny ...本研究针对杜鹃花科白珠树族冬绿群的低拷贝核基因waxy（GBSSI）与leafy的DNA序列数据，结合既往研究中的质体序列数据，对该类群的系统发育关系开展重建。我们选取109个物种开展系统发育分析，这些物种涵盖了冬绿群此前已确立的全部15个主要演化支，且覆盖了该类群的环太平洋分布范围。分析结果显示，其中两个演化支的waxy基因存在两份截然不同的部分同源拷贝，二者在系统发育树中处于彼此相隔甚远的分支位置。此外，某一个演化支的leafy基因存在两份拷贝，其余演化支仅检出1份leafy拷贝；但该拷贝与其对应的waxy拷贝同属一个主要演化支，且其在系统发育树中的定位与既往质体分析的结果相去甚远。针对所有可用相关数据开展的四基因座（waxy、leafy、内转录间隔区（Internal Transcribed Spacer，ITS）及质体基因座）联合系统发育分析，将各演化支的基因拷贝置于系统发育树中两个截然不同的位置……