The PCSK6 gene is associated with handedness, the autism spectrum, and magical ideation in a non-clinical population.

Common polymorphisms in the gene PCSK6, whose protein product mediates the development of brain and body asymmetry through the NODAL pathway, have recently been associated with handedness in three studies, making it a key candidate gene for understanding the developmental and expression of human lateralization. We tested the hypothesis that the PCSK6 VNTR polymorphism rs1053972 influences the expression of handedness and aspects of dimensional schizotypy and autism. For a sample of 709 healthy individuals, rs1053972 genotype was significantly associated with categorical measures of handedness, and with dimensional handedness in subsets of the population with high schizotypy and magical ideation or a lack of strong right-handedness. Both findings showed evidence of stronger or exclusive effects among females, compared to males. Genotypes of PCSK6 also showed significant sex-limited associations with magical ideation, a component of positive schizotypal cognition measured using the Schizotypal Personality Questionnaire, and total autism score, measured using the Autism Spectrum Quotient. These results partially replicate previous studies on effects of PCSK6 rs1053972 genetic variation on handedness phenotypes, link the PCSK6 gene with the dimensional expression of neurodevelopmental conditions in healthy individuals, and show that associations of this gene with handedness and psychological phenotypes exhibit evidence of sex-limited effects.

Social status and GnRH soma size in female convict cichlids (Amatitlania nigrofasciatus).

Gonadotropin-releasing hormone (GnRH) neurons in the preoptic area (POA) of the hypothalamus play a key role in regulating reproductive function. These neurons in turn are modulated by environmental influences, including the social environment. In both the Old World cichlid Astatotilapia burtoni and the New World cichlid Amatitlania nigrofasciatus, the size of the soma of GnRH expressing neurons in the POA varies with social status in males and breeding state in females. Dominant males have larger GnRH-releasing cells than subordinate males, and spawning females have larger GnRH-releasing cells than brooding females. A. nigrofasciatus is monogamous and both sexes engage in similar levels of aggression and territorial defense. Here we test whether female A. nigrofasciatus display GnRH-releasing cell plasticity as a function of dominant status. We find that GnRH-releasing neuron soma sizes are larger in dominant females and that this difference is independent of differences in gonado-somatic index in A. nigrofasciatus.