First, he found 24 important genes for initialization. He thought of the combination of the 24 genes.
When 24 kinds of genes were introduced, colonies were formed. Next, when 23 different genes were introduced, colonies could not be formed with 10 different genes. Then, when 10-1 = 9 kinds of genes were introduced, colonies could not be formed with 4 kinds of genes. Furthermore, 4-1 = 3 kinds of genes were introduced, all colonies could not be formed. Therefore, it turned out that four kinds of genes are important.
He succeeded in making iPS cells by incorporating four specific genes into somatic cells. In 2014, he succeeded in making the macula of the eye from iPS cells and transplanting. It is said that it will be useful for treating Parkinson's disease now.
