The chemical structure of DNA I - Genes - the units of inheritance (3/10)

Uploaded by OUlearn on 25.07.2008

This is Tübingen in southern Germany.
Its castle was the unlikely setting
for a breakthrough in molecular biology.
Friedrich Miescher was a young researcher
stationed at the laboratory here.
On the advice of his uncle, he studied the cell nucleus.
His experimental material was white blood cells
taken from the pus-soaked bandages
of wounded soldiers at the local hospital.
In the nucleus, he found protein
but he also isolated another substance,
a long, sticky molecule that he noted was rich in phosphorus.
He called it nuclein. We call it nucleic acid.
He was the first to discover DNA.
This would have been remarkable enough
but Miescher went on how to suggest how it might be used in hereditary.
In a letter to his uncle he wrote
that "molecules of DNA would be quite capable of carrying
"all the richness
"and all the variations of hereditary transmissions
"just as all the words of all languages
"can be carried by just 24 to 30 letters of the alphabet."
His predication of the genetic code came in 1892
but Miescher did not live to see it accepted
The freezing laboratory contributed to his early death from pneumonia.
But, in any case, it would be another 60 years
before science was ready to accept that DNA carried the genetic code.