My Ph.D. thesis problem was to determine if the DNA content of rat tissues increased if there was B12 in the diet. This problem was suggested by my adviser based on the observation that thymine could replace vitamin B12 in a lactobacillus.

My Ph.D. thesis problem was to determine if the DNA content of rat tissues increased if there was B12 in the diet. This problem was suggested by my adviser based on the observation that thymine could replace vitamin B12 in a lactobacillus.