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.
Shinya Yamanaka succeeded in making iPS cells in 2006. ES cells already existed as universal cells before iPS cells were created.
However ES cells have an ethical problem. Since ES cells are cells that have been taken out by breaking embryos, they are thought to be a research to pick up the buds of life, and criticism is also persistent.
And another problem is the refusal to recognize non self. IPS cells solved the problem of such ES cells.
Because iPS cells are created by removing the differentiated cells from the body, no ethical problems arise. In addition, because the cell of the patient itself can be used, no rejection reaction occurs.
