The testicles and the brain share many similarities, including genetic and functional.
- The testicles and the brain share 13,442 proteins in common.
- Both organs have the highest number of common genes among all organs.
- These similarities would be due to their involvement in speciation, the evolutionary phenomenon that led to the differentiation of species.
The testicles, the other brain of men? The question does not seem so absurd if we are to believe the results of a study carried out jointly by Portuguese and English researchers. Published on June 2 in the journal Royal Society Open Biology, it reveals that the two organs have much more in common than we imagined. In particular, they share many genetic and functional similarities. This link explains, for example, why the levels of testosterone, mainly produced by the testicles, influence character.
Many genes and proteins in common
Researchers from the University of Aveiro in Portugal and the University of Birmingham in the UK compared cell proteins from 33 types of organ tissues such as the heart, intestines, ovaries and placenta . This analysis revealed that the testicles and the brain share 13,442 proteins in common. “The brain and testicles have the most proteins in common, compared to other organs”, say the researchers. The study also found that the two organs have the most common genes of any organ.
The commonalities between the two bodies do not stop there. Indeed, the brain and the testicles are two big consumers of energy. The first to carry out complex processes like thought and the second to produce millions of sperm daily. They also both have specialized cells allowing them to maintain neurons, for the brain, and germ cells, for the testicles.
A result of evolution
Apart from their composition, the brain and the testicles have, more improbably, a similar functioning. This is seen in the behavior of neurons and testicular cells. Both types of cells practice exocytosis, a process of secretion of biomolecules from the cell to its external environment. This mechanism allows brain cells to communicate with each other through neurotransmitters. In the sperm, it is this process that is used to fuse with the egg and fertilize it.
According to the researchers, these similarities are due to their involvement in speciation, the evolutionary phenomenon that led to the differentiation of species. It is through this phenomenon that humans have managed to differentiate themselves from other animals, such as chimpanzees. This concerns in particular 60 genes which “contribute to defining human-specific phenotypic traits such as enhanced cognitive abilities”, say the authors of the study.
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