Columbia University, USA, researchers have identified a genetic pathway to sexual maturation in roundworms that show male-female brain differences.
Researchers have identified a group of genes that induces differences in the developing brains of male and female roundworms and trigger the initiation of puberty. This genetic pathway may have the same function in controlling the timing of sexual maturation in humans, potentially unlocking male-female brain differences.
What do you know about male-female brain differences?
The study, led by Columbia University scientists, offers new evidence for direct genetic effects in sex-based differences in neural development and provides a foundation to attempt to understand how the brains of men and women are wired.
Scientists have long known that puberty is accompanied by substantial changes in the brain characterized by the activation of neurons that produce hormonal signals. But what causes the brain to start releasing the hormones that switch on puberty remains elusive.
Lead study author Oliver Hobert, professor in Columbia’s Department of Biological Sciences and a Howard Hughes Medical Institute investigator explains: “Remarkably, we found that each member of this pathway is conserved between worms and humans, indicating that we have perhaps uncovered a general principle for how sexual brain differences in the brain are genetically encoded.”
“We knew the gene existed in both humans, mice and worms, but we didn’t understand how it controlled the onset of puberty,” Hobert said.
In analyzing mutant C. elegans strains, the researchers found that worms with early-onset puberty carried the mutated Lin28 gene, like humans. They also discovered three additional genes associated with premature sexual maturation, the most interesting being the fourth gene, called Lin29.
Lin29 turned out to be present only in the male brain and expressed in the central neurons, establishing a distinct difference in the neural structures of males and females. Even more interesting, male C. elegans missing the Lin29 gene had a male appearance but moved and behaved more like females.
“If you look at animals, including humans, there are dramatic physical and behavioural differences between males and females, including, for example, how they move,” Hobert said. “The Lin29-deficient male worms, in essence, were feminized.”
The researchers highlight that the study is important as it highlights that specific genes exist that control sex differences in the neural development. This study essentially opens up new questions about whether differences in male and female behaviour is hardwired in our brains.