New scientific experiments analyzed the way in which hearts are formed in the small zebrafish, the animal model that is most similar to humans, from a genetic perspective. These creatures are virtually transparent, so they can be seen through. Their rapid multiplying rates allow for studies to go very fast and very smooth. Through careful analysis, scientists discovered the role of a micro-RNA molecule, dubbed miR-138.
 

It would appear that, out of the near 650 miRNAs known to man, miR-138 is common to both zebrafish and humans. Furthermore, it plays the same role in both organisms, which is to help gene sequencing from starting and stopping at the right time, which, in turn, allows for the formation of a healthy heart from the heart tube. Without this heart tube, not even the most basic embryo could survive.
 

This 20 to 25 nucleotide-long particular strand of miRNA is special because it plays a crucial role in the formation of heart chambers, atrium and ventricles, plus the channel and the valve that separate them. "What's interesting is that a single microRNA is responsible for setting up the distinct patterning of a developing heart into separate chambers," said senior study author Deepak Srivastava M.D., director at Gladstone Institute of Cardiovascular Disease (GICD).
 

This find could be of crucial significance for people suffering from congenital heart diseases, which are conditions that occur when the heart is incorrectly formed to begin with. "Since many congenital heart defects involve abnormalities in the formation of the chambers, this is important information in finding ways of treating or avoiding those defects," Srivastava explained.
 

Increased dosages of miR-138 delivered to zebrafish that had problems with their hearts led to a better formation and definition of the heart tissue and of the overall functions of the organ. Also, deprived of the substance, the body is incapable of maturing the heart, which means that humans without this RNA strand are most likely to die from severe heart complications.