Fleeting genetic changes observed in stem cells as they differentiate could shed light on the origin of certain genetic diseases. Scientists studying stem cell differentiation usually only compare the differences in gene expression between the fully undifferentiated and differentiated cells. However, new research has revealed that the fleeting genetic changes during cell development could have lasting effects in the mature cells.

Pluripotent stem cells are unspecialised cells that can develop, or differentiate, into any type of specialised cell in the body. Scientists stimulated pluripotent stem cells to differentiate into heart muscle cells. The whole differentiation process took 16 days. Each day, the scientists recorded the differences in mRNA expression of the cells, which changed rapidly as they developed.

The eQTL method was then used to map the expressed mRNA back to the gene that originally coded for it, which revealed some interesting trends. At the start of the cell development the expressed mRNA was characteristic of stem cell mRNA, whilst towards the end of the differentiation process the expressed mRNA was characteristic of heart muscle cell mRNA. This was an expected result, and demonstrates the cell evolving into its specialised state.

However, in the middle of the cell development there were certain genes expressed that were not at any other point in the differentiation process. These expressed genes were not characteristic of either the stem cells or the heart muscle cells and were not found to be expressed in the fully differentiated cell. One expressed gene has been linked to BMI and red blood cell count. Therefore, these fleeting genetic changes could affect the phenotype of the mature cell.

Genetic diseases are often the result of many small mutations, rather than one large one. The same is true for genetic based risk factors for certain diseases, such as cancer or heart disease. Therefore, the small and rapid genetic changes that take place during cell differentiation could build up and cause a genetic disease, or an increased risk of another disease, in the differentiated cell.

More research is needed to identify what impact these fleeting genetic changes could have, but it offers an intriguing possibility that genetic diseases could be halted in the early stages of cell development.