Here I present: “Programmed Cell Death”, Victor McKusick, Mendelian Inheritance in Man’, 1966. 程序化细胞死亡。(PCD).
INTRODUCTION.
Programmed cell death (PCD) is the death of a cell as a result of events inside of a cell, such as apoptosis. PCD is carried out in a biological process, which usually confers advantage during an organism’s lifecycle. For example, the differentiation of fingers and toes in a developing human embryo occurs because cells between the fingers apoptose; the result is that the digits are separate.
Programmed cell death protein type-1 (PD1). PD type-1 is a protein encoded in humans by the PDCD1 gene. PD type-1 is a cell surface receptor on T cells and B cells that has a role in regulating the immune system’s response to the cells of the human body by down-regulating the immune system and promoting self-tolerance by suppressing T cellinflammatory activity. This prevents autoimmune diseases, but it can also prevent the immune system from killing cancer cells.
There is evidence that programmed cell death type-1 is located on cytogenetic location 2q37.3 and genomic coordinates 2:241,849,884-241,858,894 in the PDCD1 gene. The screenshot of the PDCD1 gene 9,011 bp (base pairs) of DNA sequence length is shown BELOW. Five (5) other genes besides PDCD1 in the 2q37.3 cytogenetic location are listed BENEATH. 
| Coordinate | Symbol | Genomic Name. |
| 2:241,687,020 | ING5 | Inhibitor of growth-5 |
| 2:241,734,630 | DHGDH | D-hydroxyglutarate dehydrogenase |
| 2:241,776,822 | GAL3ST | Galactose-3-O-sulfotransferase 2 |
| 2:241,809,193 | NEU4 | Neuraminidase 4 |
| 2:241,849,884 | PDCD1 | Programmed cell death 1 |
| 2:1 | TSE2 | Transsuppressor of expression 2 |
