Benoit Bruneau of the Gladstone Institute of Cardiovascular Disease explains the discovery of the first genetic link in the evolution of the heart from three- to four-chambered. He walks through the anatomy of the cold-blooded frog heart that has three chambers; talks about its differences with the warm-blooded four-chambered heart, and explains some evolutionary advantages of being warm-blooded. He explains the molecular pattern of the protein Tbx5 and how it is different in embryo frog hearts compared with embryo mammal hearts. When the protein is present throughout the entire heart, three chambers form. However, when Tbx5 is restricted only to the left side of the heart, then the wall separating the two ventricles forms and four chambers result. When irregularities in the amounts of the protein occur in human babies, congenital heart defects of the septum result.
Credit: National Science Foundation/Gladstone Institute
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