2.07 Biological Basis of Homosexuality

Before class, please read the Ganna et al 2019 science commentary by Mills.pdf posted to Canvas and complete the IKE.

In class, navigate to https://geneticsexbehavior.info/ to explore the study by Ganna et al. (2019) Large-scale GWAS reveals insights into the genetic architecture of same-sex sexual behavior, published in the journal Science. [See Biology and Society 6 on Canvas]

Learning Objectives

  1. Define homosexuality and list and explain its potential evolutionary benefits.
  2. Be able to explain, using twin studies, the evidence that no single gene or set of genes causes homosexuality in humans.
  3. Provide one hypothesis that could explain how a trait like homosexuality, which discourages production of offspring, could persist as a heritable trait in a population
  4. Know that Ganna et al 2019 studied the genetics of same-sex sexual behaviours and found support for the idea that homosexuality is a complex trait affected by many genes and also by non-genetic factors, also called environmental factors.