Scud: I never said it had to be wrong. I’m just saying that if you accept that there are no Big 5 SNPs, then the explanation must be either:
1) Personality is independent of genetics
2) The Big 5 is a poor measure of personality
or 3) We just haven’t found the personality SNPs yet because our sample sizes are too small or our stats aren’t clever enough.
I believe that the original post mistakenly implies that height SNPs have been replicated. Similarly, IQ SNPs haven’t been replicated. Height and IQ have much higher retest correlation and much higher heritability than any big 5 factor. So option 3 is pretty reasonable. Option 2 might be true, but it doesn’t help explain the data.
Fitness relevant variation should be hard to detect, because selection is purifying it. If personality is fitness-neutral, then it might be easier to detect.
Take height. Though health and nutrition can affect stature, height is highly heritable: no one thinks that Kareem Abdul-Jabbar just ate more Wheaties growing up than Danny DeVito. Height should therefore be a target-rich area in the search for genes, and in 2007 a genomewide scan of nearly 16,000 people turned up a dozen of them. But these genes collectively accounted for just 2 percent of the variation in height, and a person who had most of the genes was barely an inch taller, on average, than a person who had few of them. If that’s the best we can do for height, which can be assessed with a tape measure, what can we expect for more elusive traits like intelligence or personality?
The genome is the ultimate spaghetti code. I would not be at all surprised if some genes code for the direct opposite characteristics in the presence of other genes. It is going to take more than just running relatively simple correlation studies to untangle the functions of most genes. We are going to have to understand what proteins they code for and how they work.
http://neuroskeptic.blogspot.com/2012/03/personality-without-genes.html
The author in the comments:
Also interesting: http://blogs.discovermagazine.com/gnxp/2012/06/heritability-of-behavioral-traits
I believe that the original post mistakenly implies that height SNPs have been replicated. Similarly, IQ SNPs haven’t been replicated. Height and IQ have much higher retest correlation and much higher heritability than any big 5 factor. So option 3 is pretty reasonable. Option 2 might be true, but it doesn’t help explain the data.
Fitness relevant variation should be hard to detect, because selection is purifying it. If personality is fitness-neutral, then it might be easier to detect.
I forgot about that:
From Steven Pinker in http://www.nytimes.com/2009/01/11/magazine/11Genome-t.html
The genome is the ultimate spaghetti code. I would not be at all surprised if some genes code for the direct opposite characteristics in the presence of other genes. It is going to take more than just running relatively simple correlation studies to untangle the functions of most genes. We are going to have to understand what proteins they code for and how they work.
Yes, that’s all people claim, and I believe even this 2% claim failed to replicate.