We determined pairwise average nucleotide identity (ANI) values for the genomes of 71 strains assigned to 36 Metschnikowia species, 28 of which were represented by multiple isolates selected to represent the range of genetic diversity of the species, and most of which were defined on the basis of reproductive isolation. Similar to what has been proposed for prokaryote species delineation, an ANI value of 95% emerged as a good guideline for the delineation of yeast species, although some overlap exists, whereby members of a reproductive community could have slightly lower values (e.g., 94.3% for M. kamakouana), and representatives of distinct sister species could give slightly higher values (e.g., 95.2% for the sister species M. drakensbergensis and M. proteae). Unlike what is observed in prokaryotes, a sizeable gap between intraspecific and interspecific ANI values was not encountered. Given the ease with which yeast draft genomes can now be obtained, ANI values are poised to become the new standard upon which yeast species may be delineated on genetic distance. As borderline cases exist, however, the delineation of yeast species will continue to require careful evaluation of all available data. We also explore the often-neglected distinction between phylogenetic relatedness and sequence identity through the analysis of a tree constructed from ANI’ (100 − ANI) values.

我们确定了分配给 36 个Metschnikowia物种的 71 个菌株的基因组的成对平均核苷酸同一性 (ANI) 值，其中 28 个由多个分离株代表，选择代表该物种的遗传多样性范围，其中大部分被定义在生殖隔离的基础。类似于原核生物物种划分的建议，95% 的 ANI 值成为了酵母物种划分的良好指南，尽管存在一些重叠，因此生殖群落的成员可能具有略低的值（例如，94.3%对于M. kamakouana），不同姐妹物种的代表可以给出略高的值（例如，姐妹物种的 95.2%M. drakensbergensis和M. proteae )。与在原核生物中观察到的不同，没有遇到种内和种间 ANI 值之间的巨大差距。鉴于现在可以轻松获得酵母基因组草图，ANI 值有望成为根据遗传距离描述酵母物种的新标准。然而，由于存在临界情况，酵母物种的划分将继续需要对所有可用数据进行仔细评估。我们还通过分析由 ANI ' (100 − ANI) 值构建的树来探索系统发育相关性和序列同一性之间经常被忽视的区别。