Malnutrition and brain development.

2. During a Journal Club meeting while I was a postdoctoral fellow at Stanford University I was asked to discuss a paper by Enesco and Le Blond. This was in 1964, the early days of the DNA revolution. And these authors noted that the amount of DNA in every cell of a particular species was the same. This number was already known in many species—6.2 picagrams of DNA in every rat cell; 6.0 picagrams in every human cell. Thus the total amount of DNA in any organ indicated the number of cells in that organ, and by dividing by the amount of DNA per cell one could calculate the number of cells in that organ. Since the rest of most body cells is some form of protein, the average amount of protein per cell could be calculated. So just as the total DNA content was an indication of cell number, the protein-DNA ratio indicated cell size.