PCB 4674 Lecture Notes - Lecture 9: Scatter Plot, Heritability
29 Oct 2016
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Document Summary
Does selection on flower size imposed by bees. Step 1: estimate heritability h2, measure flower diameter of 144 flowers randomly collected 617 seeds. Seven years later, measured flowers of 57 survivors. Plotted offspring flower size vs maternal flower size (seed is from maternal parent: other parent cannot be known because that was pollen carried in by some pollinator. So midparent cannot be calculated: scatterplot. Recall this plot is offspring vs maternal parent only. Slope from just one parent estimates 1/2h2 (rather than h2) Another issue: statistical analysis reveals there are many lines with slopes not significantly worse fit than the one shown. Conclusion 0. 2 < h2 < 1. 0 flower size 20% heritable. Step 2: estimate strength of selection. Soon to flower but not yet flowered, so bias based on flower size was avoided. 14-15 total years of project so far! Step 2 6 years later: counted survivors . 6 year survival was definition of success.
