AsianScientist (Feb. 18, 2016) – A gene duplication event may have helped fish hearts adapt to aquatic environments, according to a study published in Nature Communications.
The team from University of Tokyo’s Institute of Molecular and Cellular Biosciences discovered that elastin b—a gene acquired in the course of evolution from boneless to bony fish—is responsible for turning the cardiac muscle into smooth muscle, a key step in the development of a heart structure known as the bulbus arteriosus.
Throughout history, animals have evolved and specialized their hearts to adapt to their living environments, resulting in great variation in heart shapes and function. In teleosts—bony fish such as goldfish, eels, catfish, tuna, trout, cod, herring and salmon—the heart outflow tract is transformed into an organ called the bulbus arteriosus. To form this organ, cardiac muscle had to be converted into smooth muscle over the course teleost evolution.
The bulbus arteriosus is regarded as one of the most important teleost organs for their adaptation to an aquatic environments as well as subsequent widespread diversification and spread. However, the mechanisms underlying the development and evolution of the bulbus arteriosus are largely unknown.
The team found that the teleost-specific gene elastin b regulates cell fate, causing cardiac muscle cells to develop instead into smooth muscle and thereby contributing to the development of the bulbus arteriosus.
Elastin b is known to encode for the extracellular matrix, the filling of extracellular space. This is the first report elucidating the emergence of an organ by alteration of the extracellular environment in animal evolution.
“These findings offer new understanding about a fundamental question in the life science—how organisms acquire new organs in the process of evolution,” said lead author Dr. Yuuta Moriyama.
“At the same time, this research may contribute to medical and regenerative studies of artificial modification of cardiac cell differentiation.”
The article can be found at: Moriyama et al. (2016) Evolution of the Fish Heart by Sub/Neofunctionalization of an Elastin Gene.
———
Source: University of Tokyo; Photo: Benson Kua/Flickr/CC.
Disclaimer: This article does not necessarily reflect the views of AsianScientist or its staff.
