estimated ∼88% power to detect alleles that account for 1.5% or more of the variance in one of the five main NEO-PI-R personality dimensions (at p < 1×10−5). We expect that we would have nearly 100% power to replicate these associations in samples of >2000 unrelated individuals. Unfortunately, we had only low power (∼50% or less) to replicate smaller effects even in our larger follow-up panel of about 2,000 individuals. Since we did not observe any association signals in the SardiNIA sample that replicate consistently in the follow-up samples, it seems unlikely that alleles with large effects on personality exist. Researchers interested in the genetics of personality should not be discouraged because for many other quantitative traits with a definite genetic basis, such as height, it is now clear that most associated common alleles have only modest effects (11, 90).
