Villalta Christopher F, Jacobson David J, Taylor John W
Department of Plant and Microbial Biology, University of California, Berkeley, California 94720-3102, USA.
Mycologia. 2009 Nov-Dec;101(6):777-89. doi: 10.3852/08-219.
The recent recognition of provisional Neurospora phylogenetic species (PS) 1-3 gave us the opportunity to compare genetic isolation, which underlies phylogenetic species recognition (PSR), with reproductive isolation as criteria for recognizing new species. This investigation involved first finding new individuals of PS 1-3 from a search of the Perkins culture collection, then assessing genetic isolation by PSR for old and new members of PS 1-3 and finally comparing species recognition by genetic isolation as determined by PSR to species recognition by reproductive isolation as determined by biological species recognition (BSR) and geographic distribution. To aid the search for additional members of the PS we used the genetic variation originally used to discover Neurospora PS 1-3 to easily distinguish members of Neurospora PS 1-3 from the closely related species N. crassa and N. intermedia. To increase our chance of success the analysis was performed on N. crassa and N. intermedia isolates that were either not clearly assignable to species by BSR using tester strains or were from the same geographic locations as the known members of PS1-3. Eleven new members of Neurospora PS 1-3 were identified: one new PS1, nine new PS2 and one new PS3. To complement PSR we investigated reproductive isolation with BSR in PS1-3 and the two other most closely related species, N. intermedia and N. crassa, with intraspecific and interspecific crosses. PS1 and PS2 appear reproductively isolated because they successfully mated intraspecifically and not interspecifically. PS3 isolates successfully crossed with other PS3 isolates, however they also successfully crossed with N. crassa, as previously reported, indicating that genetic isolation can precede reproductive isolation. We compared phylogenetic, mating and geographical data to challenge the use of PSR as the main criterion in the formal description of species and, having failed to discredit the approach, describe the new species, N. hispaniola (PS1), N. metzenbergii (PS2) and N. perkinsii (PS3).
最近对临时的脉孢菌系统发育种（PS）1 - 3的认识，让我们有机会将作为系统发育种识别（PSR）基础的遗传隔离与作为新物种识别标准的生殖隔离进行比较。这项研究首先从珀金斯培养物保藏中心的搜索中找到PS 1 - 3的新个体，然后通过PSR评估PS 1 - 3的新老成员的遗传隔离，最后将PSR确定的遗传隔离的物种识别与生物物种识别（BSR）和地理分布确定的生殖隔离的物种识别进行比较。为了帮助寻找PS的其他成员，我们利用最初用于发现脉孢菌PS 1 - 3的遗传变异，以便轻松地将脉孢菌PS 1 - 3的成员与密切相关的粗糙脉孢菌和间型脉孢菌区分开来。为了增加成功的机会，对粗糙脉孢菌和间型脉孢菌分离株进行了分析，这些分离株要么使用测试菌株通过BSR不能明确归为某个物种，要么来自与PS1 - 3已知成员相同的地理位置。鉴定出了脉孢菌PS 1 - 3的11个新成员：1个新的PS1、9个新的PS2和1个新的PS3。为了补充PSR，我们通过PS1 - 3以及另外两个最密切相关的物种间型脉孢菌和粗糙脉孢菌的种内和种间杂交，研究了与BSR相关的生殖隔离。PS1和PS2似乎是生殖隔离的，因为它们成功地进行了种内交配，而不是种间交配。然而，PS3分离株与其他PS3分离株成功杂交，正如之前报道的，它们也与粗糙脉孢菌成功杂交，这表明遗传隔离可以先于生殖隔离。我们比较了系统发育、交配和地理数据，以质疑将PSR用作物种正式描述的主要标准，并且在未能诋毁该方法之后，描述了新物种西班牙脉孢菌（PS1）、梅岑伯格脉孢菌（PS2）和珀金斯脉孢菌（PS3）。
