However, we think that our conclusions are unlikely to change much: first, studies in genetically more tractable organisms, such as yeast, flies and rodents, confirm the finding of genetic complexity for all phenotypes. The results are not here based on negative results: we have definite evidence of complexity. Second, as we have shown in the example of the genetic analysis of transcriptional abundance, there is no indication that alternative phenotypes will be any easier to deal with. Thus, while endophenotypes may be useful for many reasons, such as providing trait markers of susceptibility to psychiatric illness, for providing biological markers of disease and models for investigating disease process, we do not think they are likely to be any easier to dissect at a genetic level than the disorders to which they are related.
