Kerbs Benjamin, Crawford Daniel J, White Griffin, Moura Mónica, Borges Silva Lurdes, Schaefer Hanno, Brown Keely, Mort Mark E, Kelly John K
Department of Ecology & Evolutionary Biology University of Kansas Lawrence KS USA.
Biodiversity Institute University of Kansas Lawrence KS USA.
Ecol Evol. 2020 Nov 20;10(24):13990-13999. doi: 10.1002/ece3.6992. eCollection 2020 Dec.
Genome-wide genotyping and Bayesian inference method (BORICE) were employed to estimate outcrossing rates and paternity in two small plant populations of (Asteraceae) on Graciosa island in the Azores. These two known extant populations of on Graciosa have recently evolved self-compatibility. Despite the expectation that selfing would occur at an appreciable rate (self-incompatible populations of the same species show low but nonzero selfing), high outcrossing was found in progeny arrays from maternal plants in both populations. This is inconsistent with an immediate transition to high selfing following the breakdown of a genetic incompatibility system. This finding is surprising given the small population sizes and the recent colonization of an island from self-incompatible colonists of from another island in the Azores, and a potential paucity of pollinators, all factors selecting for selfing through reproductive assurance. The self-compatible lineage(s) likely have high inbreeding depression (ID) that effectively halts the evolution of increased selfing, but this remains to be determined. Like their progeny, all maternal plants in both populations are fully outbred, which is consistent with but not proof of high ID. High multiple paternity was found in both populations, which may be due in part to the abundant pollinators observed during the flowering season.
采用全基因组基因分型和贝叶斯推断方法（BORICE）来估计亚速尔群岛格拉西奥萨岛上两个小型菊科植物种群的异交率和父本情况。格拉西奥萨岛上这两个已知的现存种群最近进化出了自交亲和性。尽管预期自交率会达到可观水平（同一物种的自交不亲和种群自交率较低但不为零），但在两个种群中母本植物的子代阵列中均发现了高异交率。这与遗传不亲和系统崩溃后立即转变为高自交情况不一致。鉴于种群规模较小，且该岛最近由来自亚速尔群岛另一个岛屿的自交不亲和的殖民者定殖，以及传粉者可能稀缺，所有这些因素都通过繁殖保障来选择自交，所以这一发现令人惊讶。自交亲和谱系可能具有较高的近交衰退（ID），从而有效地阻止了自交增加的进化，但这仍有待确定。与其子代一样，两个种群中的所有母本植物均完全异交，这与高ID相符，但并非其证据。在两个种群中均发现了高多重父本情况，这可能部分归因于开花季节观察到的丰富传粉者。
