The evolutionary history of a hormone that controls sexual maturation in humans has been revealed by research from the Queen Mary University of London.
When a child's body matures into an adult body, it can be used for sexual reproduction. In some people the start of puberty is delayed and genetic analysis of this condition has provided insight into the hormonal mechanisms that control sexual maturation In 2003 it was found that puberty is triggered by the release of a hormone in the brain known as kisspeptin, which then exerts its effects by binding to aprotein known as the kisspeptin receptor. What happened to kisspeptin and itsreceptor in the evolution of life on earth?
To find genes related to the human kisspeptinreceptor, the genomes of different types of animals were analyzed. This showed the presence of genes in mollusks, annelid, and echinoderms. The researchers concluded that kisspeptin and its receptor must have come from a common ancestor of the Bilateria, an animal that exhibits symmetry during its life-cycle. Some animals, such as starfish, have a lot of genes that are kisspeptin-type receptors, while others, such as insects, do not.
The common European species Asterias rubens was chosen as an experimental model to further investigate the significance of the occurrence of an expanded family of genes. This species has eleven genes that are related to the human kisspeptin receptor and four genes that are related to kisspeptin-like molecule.
The PhD student who contributed to the study explained how this part of the study was done.
The genes that make up the kisspeptin-type receptors were cloned so that they could be expressed in cells that produce light. We were able to find the kisspeptin-like molecule that acted as a ligands for six of the eleven kisspeptin-typereceptors in starfish.
New insights into the evolution of kisspeptin have been provided by the discovery of a chemical signaling system in starfish. The findings show that the common ancestor of bilaterian animals would have had at least two types of kisspeptins.
The discovery of kisspeptin as a puberty hormone in humans was long before the discovery of SALMFamides in starfish.
The lead author of the study, Maurice Elphick, was a graduate student at the University of Florida in the 1980s when he discovered the substance in starfish.
What are the functions of the kisspeptin molecule in starfish? If there is evidence of an evolutionarily ancient role of kisspeptins as regulators of sexual reproduction in starfish, it is being investigated. Evidence of roles in other biological processes has been obtained for SALMFamides, which regulate the extra-oral feeding behavior of starfish by triggering eversion of their stomach out of the mouth. Zoological studies reveal kisspeptin's complex evolutionary history and provide new insights into its functions and relationships with other animals.
More information: Nayeli Escudero Castelán et al, Receptor deorphanization in an echinoderm reveals kisspeptin evolution and relationship with SALMFamide neuropeptides, BMC Biology (2022). DOI: 10.1186/s12915-022-01387-z Journal information: BMC Biology
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