Mating Patterns and Inbreeding Depression in Dimorphic Populations of Eichhornia paniculata (Pontederiaceae)

凤眼莲（凤眼莲科）二态性群体的交配模式和近交抑制

• 批准号: 9306473
• 负责人: Joshua Kohn
• 金额: $ 14万
• 依托单位: University of California-San Diego
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 1993
• 资助国家: 美国
• 起止时间: 1993-08-01 至 1997-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9306473&HistoricalAwards=false
• 关键词: Mating; Patterns; Inbreeding; Depression; Dimorphic

9306473 Kohn Natural populations of the emergent-aquatic annual Eichhornia paniculata often contain two readily identifiable genetic morphs whose rates of self fertilization average 0.8 and 0.2, respectively. We will take advantage of these populations to evaluate several recent theoretical predications of critical importance for understanding the evolutionary dynamics of inbreeding depression and mating system change. We will measure morph-specific levels of self fertilization and male outcrossing success to obtain complete information on morph-specific gamete transmission in these natural populations. This will provide some of the first information on how a floral morphology that increases the selfing rate affects other aspects of gamete transmission. We will evaluate morph-specific inbreeding depression to see if genes that control the mating system are in disequilibrium with fitness alleles responsible for inbreeding depression. Such associations are expected under many recent theoretical models and can alter expectations based on population mean levels of inbreeding depression. However, associations between mating and fitness alleles have not as yet been demonstrated in any natural population of hermaphroditic plants. We will resample morph frequencies in populations first examined over 10 years ago to gain information on the stability of morph ratios over time. Previous measures of transmission in these populations provided an expectation of rapid decline in the frequency of the morph with the lower selfing rate. If morph frequencies have not changed, our measures of transmission and viability should shed light on factors maintaining mating system polymorphism. If the morph with the lower selfing rate is in decline, we will gain an unusually well-documented example of evolution by natural selection over a human time scale. The results will provide useful insights into factors promoting stability or instability of mixed mating systems and t he dynamics of inbreeding depression in natural populations.***

9306473新兴潮流的eichhornia paniculata的Kohn天然种群通常包含两个易于识别的遗传变体，它们的自我受精率平均为0.8和0.2。 我们将利用这些人群来评估一些对于理解近交抑郁症和交配系统变化的进化动态至关重要的最新理论谓词。 我们将衡量特定于形态的自我施肥和男性脱落成功水平，以获取有关这些自然种群中特定于形态的配子传播的完整信息。 这将提供一些有关提高自我速度的花卉形态如何影响配子传播的其他方面的第一个信息。 我们将评估特定于形态的近交性抑郁症，以查看控制交配系统的基因是否与负责近交抑郁症的健身等位基因不平衡。 这种关联是在许多最近的理论模型下预计的，并且可以根据近交抑郁症的平均水平来改变期望。 但是，在雌雄同体的任何自然种群中尚未证明交配和健身等位基因之间的关联。 我们将在10年前首次检查的人群中重新采样变体频率，以获取有关随时间变化比率的稳定性的信息。 这些人群的先前传播措施提供了预期，即以较低的自我速度迅速下降了变体的频率。 如果变形频率没有改变，我们的传播和生存能力的度量应阐明维持交配系统多态性的因素。 如果自我速度较低的变体下降，我们将在人类时间尺度上通过自然选择来获得异常有据可查的示例。 结果将为促进混合交配系统的稳定性或不稳定性的因素以及自然种群的近交抑郁症动态提供有用的见解。***