Heterosis in COMT Val158Met Polymorphism Contributes to Sex-Differences in Children's Math Anxiety.

Math anxiety (MA) is a phobic reaction to math activities, potentially impairing math achievement. Higher frequency of MA in females is explainable by the interaction between genetic and environmental factors. The molecular-genetic basis of MA has not been investigated.

Treatment of long-term stored DNA--comparison between different methods to obtain high-quality material.

Long-term stored DNA can be sometimes the only source of genetic material of an organism that does not exist anymore, but a research interest still persists. However, there is a lack of information about useful methods to improve quality from such type of material. In this study, we compared four different protocols using DNA samples collected in 1998.