Does methylation of the brain promoter region of Cyp19 impact the development of sex-typical psychological traits?

• Author / Creator

  Bartlett, Nathan T

• While humans demonstrate sexually differentiated psychological and behavioural traits, such as aggression, there is a vast amount of within-sex variation for these traits. Further, the effect size of these sex differences is relatively small and there is a large amount of overlap between males and females on each measure. The mechanisms underlying these differences may operate, in part, prenatally. For neurodevelopment, estrogen serves to masculinize and defeminize the male brain. The aromatization hypothesis suggests that the conversion of testosterone to estrogen in the brain facilitates this process. Consequently, the degree of expression of Cyp19, the aromatase producing gene, may influence the extent to which the brain is sexually differentiated. This study assessed Cyp19 methylation levels to determine a general sex difference for the epigenetic marker and investigate the influence of the genes productivity on sex typical cognitive phenotypes. I hypothesized that males will have lower methylation levels, allowing for greater aromatase expression to masculinize and defeminize the brain. Thus, I also hypothesized that this difference would be reflected in the psychological measures, whereby lower methylation levels would be associated with more male-typical results. Aggression, mental rotation ability, and autism traits were assessed in 41 female and 36 male undergraduate psychology students, who also provided saliva samples for genomic processing. A sex difference in overall methylation levels was found, but this did not extend to the psychological measures.

• Subjects / Keywords

  • Methylation
  • Sex differences
  • Brain
  • Aromatase

• Graduation date

  Fall 2017

• Type of Item

  Thesis

• Degree

  Master of Science

• DOI

  https://doi.org/10.7939/R3PC2TP6D

• License

  This thesis is made available by the University of Alberta Libraries with permission of the copyright owner solely for non-commercial purposes. This thesis, or any portion thereof, may not otherwise be copied or reproduced without the written consent of the copyright owner, except to the extent permitted by Canadian copyright law.