https://www.sciencedirect.com/science/article/pii/S1053811921002317

Heres an example of an A- candidate gene study finding heterozygosity functions more efficiently in the thinking brain. Since NPA theory posits A- trait gene as dominant, what does this say about the finding that homozygous A- trait gene would be less efficient in brain function than heterozygous A- trait gene. Possibly, this relates to a possible A= trait gene being homozygous??