Sexual adaptation across evolution: the neural basis of female sexual motivation

Descripción del proyecto

Por qué el comportamiento animal varía tanto dentro de una misma especie y entre especies diferentes

Los científicos saben poco sobre los mecanismos moleculares que subyacen al comportamiento sexual femenino, a pesar de su papel crucial en la reproducción. La mayoría de las investigaciones se han centrado en los comportamientos de apareamiento de los machos, dejando inexplorada en gran parte la motivación sexual de las hembras. Un misterio clave es cómo las distintas especies muestran comportamientos sexuales tan diferentes, incluso estando estrechamente emparentadas. El equipo del proyecto EvoSexDrive, financiado por el CEI, pretende colmar esta laguna estudiando dos especies emparentadas de nematodos («C. elegans» y «C. afra»), que difieren en sus estrategias de apareamiento. Los hermafroditas de «C. elegans» son indiferentes al apareamiento, mientras que las hembras de «C. afra» están muy motivadas para aparearse. Se espera que en el proyecto se descubra cómo evolucionan los comportamientos a lo largo del tiempo y cómo los controlan los genes.

Objetivo

What are the molecular mechanisms that determine intra- and inter-species behavioral variation? We propose to address this key outstanding question in evolutionary neuroscience by exploring a striking example of adaptive evolution of female sexual behavior. Comparing two closely related nematode species that use different mating strategies, we discovered that while androdioecious (hermaphrodite-male) C. elegans hermaphrodites are indifferent to males, dioecious (female-male) C. afra females exhibit a pronounced sex drive, actively engaging in and initiating mating. Importantly, we found that under induced reproductive pressure, the passive hermaphrodites switch to female-like behavior, suggesting the existence of a suppressed neuronal circuit.
In this proposal, we will employ an evolutionary comparative approach to deconstruct the neural basis of female sexual motivation, by addressing three objectives: (1) Explore and quantify the extent and molecular basis of female sexual motivation in C. afra. (2) Characterize the neuronal underpinnings of sexual attraction, by mapping gene expression, connectivity, and network dynamics in females, and (3) Investigate how mating pressure promotes sexual adaptation in C. elegans hermaphrodites, by monitoring the evolving changes in genetics, epigenetics, and the neuromodulatory network in transition states from passive to active sexual behaviors.
Our suggested program challenges long-held assumptions about the role of female sexual motivation, which despite its complexity remains understudied compared to male mating behaviors. Our unique approach, utilizing the power of C. elegans alongside tool building for investigating C. afra, will not only unveil the molecular mechanisms governing the emergence of novel female sexual behaviors but also create a blueprint for understanding their evolution.