A genetic approach to dissect sexually dimorphic behaviors

Abstract

It has been known since antiquity that gender-specific behaviors are regulated by the gonads. We now know that testosterone is required for the appropriate display of male patterns of behavior. Estrogen and progesterone, on the other hand, are essential for female typical responses. Research from several groups also indicates that estrogen signaling is required for male typical behaviors. This finding raises the issue of the relative contribution of these two hormonal systems in the control of male typical behavioral displays. In this review we discuss the findings that led to these conclusions and suggest various genetic strategies that may be required to understand the relative roles of testosterone and estrogen signaling in the control of gender specific behavior.All animals exhibit sex differences in behavior that are characteristic of the species. Such gender typical behaviors are often used to court mates, to defend territory and other resources, and to procure food for mates and offspring. These sexual dimorphisms in behavior are often innate and can be displayed without prior social experience or training, suggesting that the neural circuits that mediate these behaviors are developmentally hardwired in the brain. Nevertheless, the display of these behaviors is tightly regulated by external sensory cues as well as internal physiological regulators such as hormones. Such dual control ensures that animals engage in these behaviors only at the appropriate time and circumstance. While we have learned much about the sensory and hormonal control of sexually dimorphic behaviors (Morris et

Genetic dissection of neural circuits underlying sexually dimorphic social behaviours

“…Therefore, the neural pathways underlying sex-typical social behaviours are embedded within an assortment of neural circuits involved in many unrelated behaviours. The use of conditional genetic approaches is necessary to study the neurons relevant for social behaviours in isolation from their functionally distinct neighbours [107][108][109]. The use of mice genetically modified to express Cre in molecularly defined neuronal subpopulations of neurons in conjunction with virally encoded Cre-dependent transgenes has permitted projection-mapping as well as functional characterization of these neurons.…”

Estrogen Masculinizes Neural Pathways and Sex-Specific Behaviors

“…Both testosterone and estrogen are required for male behaviors in many vertebrates, including mammals. It remains to be determined how these two hormonal pathways intersect to control dimorphic behaviors in males (Juntti et al, 2008). …”

The Androgen Receptor Governs the Execution, but Not Programming, of Male Sexual and Territorial Behaviors

“…Thus, AR and ERα, β are widely expressed in inter-connected limbic regions such as the medial amygdala, the bed nucleus of the stria terminalis, and the preoptic hypothalamus. Despite numerous studies documenting a role for testosterone in male specific patterning of gene expression and behavior, the extent to which this hormone signals through AR for masculinizing the brain and behavior remains unclear (Juntti et al, 2008). …”