Our brains have a surprising amount of genes and proteins in common with the male gonads , being, in fact, the most similar organ to the brain compared to any other organ in the body. This is the surprising conclusion of the study led by the University of Aveiro in Portugal and published in the journal The Royal Society, which defends this comparison, and exposes the biological similarities between testicles and brains . What they have in common, the researchers argue, can help us understand the conditions that affect both and find better ways to treat them.
The scientists compared proteins from 33 types of tissues including the brain, testes, heart, cervix, and placenta, finding that the testes and our thinking organ have more than 13,000 proteins in common , many of which are involved in tissue development and cell communication.
“The highest number of common proteins was observed between the brain and the testes, suggesting that the human brain and testes are the most similar tissues in the human body,” the researchers wrote. “Of the total of 14,315 and 15,687 proteins that make up the human brain and the testicular proteome, respectively, 13,442 are common to both tissues.”
The two parts of the body also share a large number of genes. “A large-scale analysis of the expression of 33,689 genes in 15 human tissues revealed that the human brain and testes shared the greatest similarity in gene expression ,” the experts revealed.
The research also found similarities in human neurons and sperm, as both undergo exocytosis: neurons use this process to pass neurotransmitters to each other and sperm use it when they fuse with an egg (exocytosis is the process in which the material from inside a cell is moved to an outside environment).
“This is a little explored topic, and the connection between these tissues needs to be clarified, which could help to understand the dysfunctions that affect the brain and testicles, as well as to develop improved therapeutic strategies,” comment the authors.
Previous studies have suggested that there are links between sexual dysfunction and brain disorders, and even a tactical association between intelligence and semen quality. Although these links don’t mean much on their own, scientists have just found an explanation for why they might exist.
Why are there so many coincidences between the brain and the testicles?
How the brain came to be so similar to a pair of testicles is not fully understood , although the study authors propose that it may be the product of a process called speciation . According to this theory, the testes could have participated in human speciation along with the placenta and the brain, which could have contributed to both tissues having the same set of genes.
Referencia: Royal Society Open Biology. 2021 Brain and testis: more alike than previously thought? Bárbara Matos , Stephen J. Publicover , Luis Filipe C. Castro , Pedro J. Esteves and Margarida Fardilha Published:02 June 2021https://doi.org/10.1098/rsob.200322
