Aversion to Cilantro? Please...

Here is a study claiming to find a link between some gene and not liking cilantro.  The fact that this is obviously going to be another study that finds a false positive and tries to sell it as a big new finding is inevitable.  Here is the tipoff before even looking at the study:

Eriksson says that nearly half of all Europeans have two copies of this variant, and of those people, 15 percent reported a soapy taste. In contrast, 13 percent of Europeans had no copies, and 11.5 percent of this group said cilantro tasted like soap.

If someone wants to defend this study, particularly the authors, I will actually go through the study and mock it specifically, but otherwise I don't think it is even worth debunking.  Clearly, Nature Journal has no sense of quality control.   They will print any study making any absurd claim.

Plomin & Craig, 2001: The genetics of intelligence (g) - Takin' it to the Brits

This was one of my favorite letters to write.  I was passing some time in the "library" at my job and there happened to be a British Journal of Psychiatry sitting on the table.  I pick it up and, lo and behold, there is a study purporting to show a genetic link for g (a fanciful version of I.Q).  I'm sure the authors didn't intend it, but this kind of stuff is really not much different than old time eugenics.  I decided to challenge the assertions and sent the BJP a letter.  To my surprise, they printed it with a reply from the authors.  I was quite amused that they changed my "randomization" to "randomisation" for the Brit-friendly audience.  I also didn't know that they call raisins "sultanas" there.  Rather than post the letter and the reply from the authors (which is linked above), I'll just make a few points:

Ten Years Later: Where's the Beef? My letter to AJP RE: Stephen V. Faraone, Ph.D., et al. claim that D4 receptor linked to ADHD using Meta-analysis as proof...

I can be a mean bugger sometimes.  I read some of my old letters and I think, “Am I still that angry?”  I wish I could say no.   In any case, this letter  of mine from 2002 was published by the American Journal of Psychiatry along with  a reply; a reasonably polite one, I must admit, when I compare it to my original in retrospect.  In it, they seemed to suggest that my point wasn’t clear on a couple of occasions. I was happy enough that the American Journal of Psychiatry printed my abrasive and contrary letter, but now that any fool can have his own personal blog, I will see if I can make it clearer.  Here I will print their response and explain my case:

1.We agree that meta-analysis can be misinterpreted if an original positive finding is included. Dr. Pittelli overlooked our Table 3, which showed that the meta-analysis was significant when this study was exclude. 

2. There is no statistical basis for Dr. Pittelli’s assertion that a meta-analysis is biased if it includes a study from the person who performed the meta-analysis. He also overlooked Table 4, which showed that the meta-analysis was significant after omission of our study. Dr. Pittelli claims that research presented at national conferences or solicited from the ADHD Molecular Genetics Network e-mail list is biased; this is incorrect. The main bias of concern to meta-analysis is that negative studies are published, not that conference reports are more positive than published studies. Dr. Pittelli asks why we think it unfortunate that studies of ADHD and the D₄ receptor gene have not consistently confirmed their association. It is unfortunate because the use of small study groups to detect small effects obscures findings and inhibits progress.
3. The claim that a meta-analysis of studies of ADHD and the D₄ receptor gene must include all other genes tested makes no sense. Studies of different genes test different hypotheses. Mixing apples and oranges does not clarify any statistical analysis.
4. Dr. Pittelli incorrectly claims that whether ADHD genes truly exist remains an unproven assumption. The twin literature about ADHD clearly indicates that ADHD is one of the most heritable of psychiatric disorders (1). Moreover, the genetics literature is consistent with a multigenic theory of ADHD (2), despite Dr. Pittelli’s claim that such a theory is circular.We never claimed that our meta-analysis proved the D₄ receptor gene to be a susceptibility gene for ADHD. We concluded that the extant data were strong enough to warrant further studies of the D₄ receptor gene and ADHD.

Alright, I will try to answer all their points by giving a hypothetical meta-analysis below the fold: