EDIT: Ouch, I was wrong. Apparently, there are many single nucleotide polymorphism, that come up in GWAS and which are NOT in protein coding regions. Non-protein-coding SNPs actually constitute 90 percent of stuff found in GWAS !!!
The other part of my argument still stands. There are other variations in DNA apart from single nucleotide polymorphisms, like repeats. And they would not show up in GWAS.
Previous text:
At a bioinformatic summer school, there was a talk, that humans and apes chimpanzees have very similar genes. And many scientists believe, that the most important difference between humans and chimps does not lie in the sequences of protein coding genes. Rather, it is suspected, that the regulatory regions are the thing that matter most. It may be more important how much of certain proteins is produced rather than what exactly those proteins look like. This “how much” question is regulated by other proteins, but also by weird things like how far away some genes are distanced from each other by non-coding DNA areas, how are the non coding DNA areas spatially folded. Some regulation is achieved by repeats, too.
So, duh, I am not surprised, that GWAS sees less genetic effects than twin studies. (RETRACTED PART The GWAS is focusing on protein coding genes almost exclusively.) It is focusing on minuscule point differences—single nucleotide polymorphisms ! It covers just a part of what matters in DNA variability.
EDIT: Ouch, I was wrong. Apparently, there are many single nucleotide polymorphism, that come up in GWAS and which are NOT in protein coding regions. Non-protein-coding SNPs actually constitute 90 percent of stuff found in GWAS !!!
The other part of my argument still stands. There are other variations in DNA apart from single nucleotide polymorphisms, like repeats. And they would not show up in GWAS.
Previous text:
At a bioinformatic summer school, there was a talk, that humans and apes chimpanzees have very similar genes. And many scientists believe, that the most important difference between humans and chimps does not lie in the sequences of protein coding genes. Rather, it is suspected, that the regulatory regions are the thing that matter most. It may be more important how much of certain proteins is produced rather than what exactly those proteins look like. This “how much” question is regulated by other proteins, but also by weird things like how far away some genes are distanced from each other by non-coding DNA areas, how are the non coding DNA areas spatially folded. Some regulation is achieved by repeats, too.
So, duh, I am not surprised, that GWAS sees less genetic effects than twin studies. (RETRACTED PART The GWAS is focusing on protein coding genes almost exclusively.) It is focusing on minuscule point differences—single nucleotide polymorphisms ! It covers just a part of what matters in DNA variability.