文献类型：期刊文献

英文题名：A comparison of reproductive isolation between two closely related oak species in zones of recent and ancient secondary contact

作者：Liao, Wan-Jin[1,2] Zhu, Bi-Ru[1,2] Li, Yue-Fei[1,2] Li, Xiao-Meng[1,2] Zeng, Yan-Fei[3] Zhang, Da-Yong[1,2]

第一作者：Liao, Wan-Jin

通信作者：Liao, WJ[1];Zhang, DY[1];Liao, WJ[2];Zhang, DY[2]

机构：[1]Beijing Normal Univ, Coll Life Sci, State Key Lab Earth Surface Proc & Resource Ecol, Beijing 100875, Peoples R China;[2]Beijing Normal Univ, Coll Life Sci, MOE Key Lab Biodivers Sci & Ecol Engn, Beijing 100875, Peoples R China;[3]Chinese Acad Forestry, Res Inst Forestry, Key Lab Tree Breeding & Cultivat, State Forestry Adm, Beijing 100091, Peoples R China

年份：2019

卷号：19

期号：1

外文期刊名：BMC EVOLUTIONARY BIOLOGY

收录：;Scopus(收录号：2-s2.0-85062501786);WOS:【SCI-EXPANDED(收录号:WOS:000460749200001)】；

基金：This work was financially supported by the National Key R&D Program of China (2017YFA0605100), the National Natural Science Foundation of China (31370398, 31270701) and the State Key Laboratory of Earth Surface Processes and Resource Ecology (2017-FX-05). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.

语种：英文

外文关键词：Ancient contact zone; Hybridization; Postzygotic; Quercus; Recent secondary contact; Reproductive isolation; Temporal differentiation

摘要：BackgroundMuch of the debate over the evolutionary consequences of hybridization on genetic divergence and speciation results from the breakdown or reinforcement of reproductive barriers in secondary hybrid zones. Among hybrid populations established for different lengths of time following secondary contact, stronger reproductive barriers are generally expected to occur in zones with longer contact. However, in plants no detailed investigation of recent and ancient zones of secondary contact has been conducted despite the importance of such a comparative study. Here, we compare pre- and postzygotic reproductive barriers between two closely related oak species, Quercus mongolica and Q. liaotungensis, in such a situation.ResultsThe recorded flowering times of both species overlapped in both contact zones. The fruit set at 10 and 30days after interspecific hand pollination was not significantly lower than that after intraspecific pollination whenever Q. mongolica or Q. liaotungensis comprised the maternal parents in both populations. These results indicated that neither prezygotic phenological barriers nor interspecific incompatibility could have resulted in the reproductive isolation between the two species in both hybrid zones. However, the proportion of hybrid seeds produced by both species in the ancient zone was significantly lower than that recorded in the recent zone of secondary contact. In addition, the proportion of hybrid seeds simulated to form, assuming both random mating and an absence of postpollination barriers, was significantly higher than that detected in the ancient contact zone but not in the recent contact zone. These results suggest stronger early-acting postzygotic isolation between the two oak species in the ancient relative to the recent contact zone.ConclusionsOur comparative study demonstrated that postzygotic barriers during seed maturity were the main contributing factor to total reproductive isolation, particularly in the ancient contact zone, which aided species delimitation. In the recently formed secondary contact zone, pre- and postzygotic barriers were not well developed, and a high frequency of natural hybridization was evident. To our knowledge this study provides the first comparison of reproductive isolation between the ancient and recent secondary contact zones in plants and helps to clarify the evolutionary consequences of hybridization in a temporal context.