Detection of hybrids in nature: application to oaks (Quercus suber and Q-ilex)
Detection of hybrids in nature: application to oaks (Quercus suber and Q-ilex)
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DOI：
10.1038/hdy.2009.8
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发表时间：
2009-05-01
期刊：
影响因子：
3.8
通讯作者：
Gil, L.
中科院分区：
文献类型：
--
作者：
Burgarella, C.;Lorenzo, Z.;Gil, L.
为了更好地了解基因渗入的功能和动态，需要对自然界中的第一代 (F1) 杂交体和回交进行强大而准确的检测。为了记录两种地中海常绿橡树——栓皮栎（Quercus suber）和圣栎（Q. ilex）之间正在进行的种间基因交换的频率，我们使用八个微卫星位点和两种贝叶斯聚类方法（在程序 STRUCTURE 和 NEWHYBRIDS 中实施）分析了来自这两个物种范围内的 1487 个个体。模拟数据用于评估两种聚类方法之间的差异，并支持后验概率阈值的选择，以区分混合个体和纯个体。我们发现，使用 STRUCTURE 可以实现最高的混合动力检测能力，而 NEWHYBRIDS 则提供最高的准确度。无论采用何种方法，这两个物种在没有任何先验信息的情况下都被清楚地区分为独立的遗传实体。与之前的报道相反，我们没有发现单向渗入的证据。总体杂交率非常低（基因渗入个体的<2%）。只有两个个体被鉴定为 F1 杂种，五个个体被鉴定为早期回交。这项工作表明，两种互补的贝叶斯方法的组合应用及其通过模拟进行的系统验证，适合当前的情况，有助于在混合个体的识别中获得解决方案。遗传 (2009) 102, 442-452; doi：10.1038/hdy.2009.8； 2009 年 2 月 25 日在线发布
Powerful and accurate detection of first-generation (F1) hybrids and backcrosses in nature is needed to achieve a better understanding of the function and dynamics of introgression. To document the frequency of ongoing interspecific gene exchange between two Mediterranean evergreen oaks, the cork oak (Quercus suber) and the holm oak (Q. ilex), we analyzed 1487 individuals originating from across the range of the two species using eight microsatellite loci and two Bayesian clustering approaches (implemented in the programs STRUCTURE and NEWHYBRIDS). Simulated data were used to assess the differences between the two clustering methods and to back up the choice of the threshold value for the posterior probability to discriminate admixed from pure individuals. We found that the use of STRUCTURE resulted in the highest power to detect hybrids, whereas NEWHYBRIDS provided the highest accuracy. Irrespective of the approach, the two species were clearly distinguished as independent genetic entities without any prior information. In contrast with previous reports, we found no evidence for unidirectional introgression. The overall hybridization rate was very low (< 2% of introgressed individuals). Only two individuals were identified as F1 hybrids and five as early backcrosses. This work shows that the combined application of the two complementary Bayesian approaches and their systematic validation with simulations, fit for the case at hand, helps gain resolution in the identification of admixed individuals. Heredity (2009) 102, 442-452; doi: 10.1038/hdy.2009.8; published online 25 February 2009