[QUOTE=Morril]Very interesting!
But how are you conducting this study?
Do you also compare MZ's who lived together all life with MZ's who have been seperated? To see if the differrence in enviroment/social place are important for them
Are there any "pre-conclusions" of the study?[/QUOTE]
No, we don't compare MZ reared together and apart, for the simple reason that there are hardly any MZ's reared apart in Sweden. Those pairs when one or both twins have been adopted are extremely rare since child adoption of Swedish children does not exist here except in very special cases, like if you want to adopt your partners children from previous marriage and their biological other parent is dead. Twins where one or both siblings are raised in foster homes don't work either, because kids only get placed in foster homes if the parents are totally unable to take care of them, such as cases of severe chronic psychiatric disorder or abuse of the children. Since my studie is of healthy twins with no heritage for psychiatric disorder (on the contrary, they are going to function as a control group for 2 planned twin studies of disorder), twins raised in foster home cannot be used.
However, there are two ways to estimate the effect of nature-nurture, and one is the classical MZ reared apart and together-paradigm where the variance is environmental factors. The other is the paradigm I utilise, MZ-DZ where the variance is genetic factors. So both ways lead to an estimation of the ration genetic/non-genetic factors.
In my study, we investigate two different receptors with PET, one dopamine receptor and one serotonin receptor. I also perform personality and cognitive tests on them. We have not started with the DZ group yet (I'm just trying to recruit them), so there are no conclusions yet, not even preliminary, apart from the obvious - the brains of MZ twins are quite similar but not identical.
In Denmark, there is also twin studies going on, and I know that my colleagues at Rigshospitalet are doing a big twin study with PET, where they examine another serotonin receptor
PS - Swedish Televison are going to make a short documentary about our research in 2 weeks, so I could send you a copy if I can get one
