January 30, 2011
by peter.taylor
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In studies of heritability, a field in which path analysis originated, there are no measured variables except the observed focal variable (e.g., height). Path analysis can still be used if we convert the additive model on which any given Analysis … Continue reading
January 26, 2011
by peter.taylor
3 Comments
Idea: As conventionally interpreted, heritability indicates the fraction of variation in a trait associated with “genetic differences.” A high value indicates a strong genetic contribution to the trait and “makes the trait a potentially worthwhile candidate for molecular research” that … Continue reading
October 19, 2010
by peter.taylor
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“Troubled by Heterogeneity? Opportunities for Fresh Views on Long-standing and Recent Issues in Biology and Biomedicine,” was a talk I gave on 13 Oct. ’10 (abstract). I sketched a number of cases to get the audience thinking about my underlying … Continue reading
October 16, 2010
by peter.taylor
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“What does it mean to say IQ test scores are largely genetic? Does this make you think that differences among IQ scores between races are genetic?” Starting with these two questions, I aim to get an audience of high school … Continue reading
September 19, 2010
by peter.taylor
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By the 1950s the “neo-Darwinian” or “modern synthesis” in evolutionary theory had discounted or even rejected the significance to evolution of characters acquired in an organism’s lifetime. It became taboo to express sympathy with Lamarck. The irony is that the … Continue reading
September 17, 2010
by peter.taylor
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The first installment ended on the following note: Suppose you have many sets of same-sex non-identical twins raised together and many sets of same-sex identical twins raised together and find that the identical twins are on average more similar. It … Continue reading
September 16, 2010
by peter.taylor
1 Comment
Many people say Nature vs. Nurture is an ill-framed formulation, but the challenge is to explain why in a way that accounts for the persistent popularity of that formulation. We know, for example, that both genes and environment are involved … Continue reading
September 14, 2010
by peter.taylor
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The possibility of underlying heterogeneity makes heritability studies even less informative than, as prominent geneticists have noted (e.g., Rutter 2002, 4), the method of data analysis not suggesting where to look for the underlying genetic factors that contribute to heritability. … Continue reading
September 12, 2010
by peter.taylor
2 Comments
What can researchers do on the basis of knowing a trait’s heritability if the genetic and environmental factors underlying the observed trait are heterogeneous, or if the method of data analysis does not allow researchers to rule out the possibility … Continue reading
September 11, 2010
by peter.taylor
3 Comments
Consider claims that some human trait, say IQ test score at age 18, show high heritability. These claims can be derived from analysis of data from relatives. For example, the similarity of pairs of monozygotic twins (which share all their … Continue reading