If you had a genome in front of you, would you be able to tell what a person’s strengths/weaknesses, or overall behavioral characteristics are? With what percentage would you expect to be correct? Are there any people involved with creating genetic profiles (gene A and gene B mean something separately, but together mean a different behavioral component)?
According to some solid predictions, all newborn babies’ DNA will be sequenced soon after birth. This means that no more genotyping will ever need to be done on their DNA. The big question is what will we be able to do with this information. Currently, there is very very little that we can tell about psychological characteristics of an individual just by examining their DNA. This is because all psychological traits are influenced by many many genetic markers of very very small effects (the concept called ‘polygenicity’). This means that it is very difficult to identify these markers. However, recently this work has begun. For example, here you can find a paper that reports on predicting educational achievement from DNA, where 9% of variability in achievement is explained by multiple DNA markers (polymorphisms). To hear the author talk about her work please see here
My family is currently undergoing genetic testing because of my child’s autism diagnosis, with no family history. We already did the microarray, now we’re doing single-gene tests (over 2,000!). My question is, what about traits that are a result of interplay between multiple genes?
As you probably know, our view of autism and autistic spectrum disorder (ASD) has changed dramatically, from viewing it as an entirely environmental condition (parents were often blamed for it) to viewing it as a ‘genetic’ disorder. Neither view is correct. Like most other traits, it seems to be a product of genetic and environmental influences. The environmental side of it is very poorly understood, it is really not clear what aspects of the environment contribute to the development of the condition. At the genetic level, a lot has been learned from family studies, and in particular – twins. Monozygotic twins who share 100% of their DNA show a remarkably high concordance for autism (if one twin has ASD, the other one is highly likely to also be diagnosed with it). Interestingly, Dizygotic twins (who share only 50% of the variable DNA) are less similar than can be expected from their genetic similarity. This indicates, that it is possible that some of the genetic effects on ASD are of an interactive type – when one gene depends on another gene (epistasis). What is also clear is that many many genetic markers (polymorphisms) seem to be involved in ASD, and currently only some of them have been identified. So, still a lot of research to do…