Friday, April 6, 2012

Frederick Griffith

Frederick Griffith was an Englishman who studied bacteriology. His experiment is famous for elucidating the "transforming factor" in genetics. He worked with two strands of Streptococcus pneumoniae, one a smooth strain (produced smooth colonies on growth media) and the other a rough strain (produced rough colonies on growth media).
Frederick Griffith

In his experiment, Griffith infected mice with the S strain and with the R strain. The mouse with the S strain died, while the one that received the R strain survived. He then heat-killed the S strain and administered it to a mouse. The mouse survived. The next step in his experimental processed was to combine heat-killed S strain and live R strain, which he gave to the mouse. The mouse died! Through this he concluded that the dead S strain must have given the live R strain something, which he called a transforming factor. The experiment is summarized by this picture:

Through other experiments scientists discovered this transforming factor was in fact DNA. Frederick Griffith is a very important person in the history of genetics!

Do you know how Frederick Griffith died? Do you know why the S strain was deadly and why the R strain was not? Also, does this post count as double, for F and G?! Just kidding. You're still getting a G :)


Anna Smith said...

Haha yeah count it as both and give us same post tomorrow! That picture is bringing a tear to my eye, poor lil mousies :)

Gossip_Grl said...

Sounds interesting!

soggy in the corner said...

Interesting! Now if they only would avoid using DNA to do bad that thing with the ferrets and the bird flu thing.

Grammy said...

Hi, great post and so very informative. I hate getting the flu shots...and avoid them whenever possible. I guess we have a lot to thank scientists for, don't we?
Trying to visit all challengers this month as well as write my own. Regards to you. Keep up the good work. Ruby

EmptyNester said...

Well. That post went right over my head. :) I'm so glad there are math and science people out there so that english and history people like me don't have to worry about it. LOL

MOV said...


this is like a free science class every day! love it!

can't wait to see what your write tomorrow.


Donna K. Weaver said...

Wow. Confusing but fascinating, too. Poor mice.

Ros said...

Never mind the S strain. How about brain strain? (which is what I have right now LOL)

Good to see another blogger in the A-Z Challenge.


cherie said...

Fascinating subject! I was a Biology major in college. So this definitely piqued my interest!