Time to call the Love Doctor???

Time to call the Love Doctor???

It is widely recognized that DNA influences many aspects of one’s being: eye color, hair color, stature, and even the propensity for developing specific diseases.  But to what extent does genetics dictate human behavior and pleasure?  Interestingly, research is beginning to evidence that many facets of sexuality—including desire, arousal, performance, and orgasm—may be impacted by single nucleotide polymorphisms (SNPs) within the genes.  

Ohh-la-la!

Now that I have your attention, let’s proceed to the science.

Ladies first! 

Two hormones, estrogen and oxytocin, play vital roles in female sexuality.  In a study of Greek heterosexual women, Armeni et al. (2017) investigated SNPs on the estrogen receptor a (ERA) and oxytocin receptor (OXTR) genes.  Utilizing a questionnaire called the Female Sexual Function Index (FSFI), the researchers were able to quantify the effect of the SNPs on sexual desire, arousal, lubrication, orgasm, satisfaction, and pain.  They found that women with the OXTR rs53576 (A) polymorphism reported higher levels of arousal, while the ERA rs2234693 (T) polymorphism resulted in both higher arousal and lubrication scores (Armeni et al., 2017).  Notably, the occurrence of OXTR rs53576 (A) and ERA rs2234693 (T) together was associated with increased arousal, orgasm, and total FSFI scores, suggesting a potential synergistic effect (Armeni et al., 2017).

Your turn, fellas!

Premature ejaculation is a common symptom of sexual dysfunction reported among men.  To elucidate the relevance of oxytocin (OXTR) and the arginine vasopressin (AVPR) 1A and 1B receptor genes on this aspect of male sexuality, Jern et al. (2012) collected salivary samples and questionnaires regarding ejaculatory function from male twins as well as non-twin brothers of those twins.  They found that one SNP in particular, OXTR rs75775 (G:T), was associated with a significantly greater risk of premature ejaculation as compared to homozygotes G:G or T:T. The authors also noted that while there were several other apparently causative SNPs present on the AVPR gene, the majority of them were so rare that a larger sample size would be needed in order to identify clear effects on ejaculatory function.

Lastly, dopamine, and the DRD4 receptor in particular, appears to play a significant role in human sexuality.  Zion et al. (2006) stated that SNPs within the C-521T and C-616G promoter regions of this gene displayed associations with human sexual behavior, and that these allelic variations may partly account for diversity in sexual desire, arousal, and overall function.  Interestingly, a dopamine D4 agonist was able to produce an erection in a rat study and may show promise in the treatment of erectile dysfunction (Zion et al., 2006).

Fortunately, continued genetic testing and research helps us to get to know ourselves (and, in this case, our partners) a little bit better.

HAPPY VALENTINE’S DAY!

Written by NGI intern: Sam Minns and NGI

REFERENCES

Armeni, A.K., Assimakopoulos, K., Marioli, D., Koika, V., Michaelidou, E., Mourtzi, N.,…Georgopoulos, N.A.  (2017).  Impact of estrogen receptor a gene and oxytocin receptor gene polymorphisms on female sexuality.  Endocrine Connections, 6(1), 44-52. 

Jern, P., Westberg, L., Johansson, A., Jonsson, L., Corander, J., Sandnabba, K., & Santtila, P.  (2012).  Are single nucleotide polymorphisms in the oxytocin and vasopressin 1A/1B receptor genes likely candidates for variation in ejaculatory function?  BJU International, 110(11c), E1173-E1180.

Zion, Z.B., Tessler, R., Cohen, L., Lerer, E., Raz, Y., Bachner-Melman, R.,…Ebstein, R.P.  (2006).  Polymorphisms in the dopamine D4 receptor gene (DRD4) contribute to individual differences in human sexual behavior: desire, arousal, and sexual function.  Molecular Psychiatry, 11, 782-786.

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