Data from: Somatic deleterious mutation rate in a woody plant: estimation from phenotypic data

We conducted controlled crosses in populations of the long-lived clonal shrub, Vaccinium angustifolium (lowbush blueberry) to estimate inbreeding depression and mutation parameters associated with somatic deleterious mutation. Inbreeding depression level was high, with many plants failing to set fruit after self-pollination. We also compared fruit set from autogamous pollinations (pollen collected from within the same inflorescence) to fruit set from geitonogamous pollinations (pollen collected from the same plant but from inflorescences separated by several meters of branch growth). The difference between geitonogamous versus autogamous fitness within single plants is referred to as "autogamy depression" (AD). AD can be caused by somatic deleterious mutation. AD was significantly different from zero for fruit set. We developed a maximum likelihood procedure to estimate somatic mutation parameters from AD, and applied it to geitonogamous and autogamous fruit set data from this experiment. We infer that on average, approximately three sublethal, partially dominant somatic mutations exist within the crowns of the plants studied. We conclude that somatic mutation in this woody plant results in an overall genomic deleterious mutation rate that exceeds that measured to date for annual plants. Some implications of this result for evolutionary biology and agriculture are discussed.本研究针对长寿克隆灌木狭叶越橘（Vaccinium angustifolium，俗称矮丛蓝莓）的种群开展控制性杂交实验，以估算与体细胞有害突变（somatic deleterious mutation）相关的近交衰退（inbreeding depression）及突变参数。实验中近交衰退程度较高，多数植株在自花授粉后无法坐果。我们还比较了自交传粉（autogamous pollinations，即从同一花序内采集花粉）与同株异花序传粉（geitonogamous pollinations，即从同一植株但取自相隔数米枝条的花序采集花粉）的坐果情况。单株内同株异花序传粉与自交传粉的适合度差值被定义为“自交衰退（autogamy depression，AD）”，该类自交衰退可由体细胞有害突变引发。坐果相关的AD数值显著不为零。我们开发了一套最大似然分析流程，用于基于AD数据估算体细胞突变参数，并将其应用于本实验的同株异花序传粉与自交传粉坐果数据集。经推断，在所研究的植株冠丛中，平均存在约3个亚致死、部分显性的体细胞突变。本研究得出结论：该木本植物的体细胞突变所产生的基因组整体有害突变率，高于目前已报道的一年生植物的有害突变率。最后，我们讨论了该研究结果对进化生物学与农业研究的若干启示。