If you visit, Google.com today, you will be greeted with a special doodle honoring the 189th birthday of Gregor Mendel, a monk, who is considered to be the father of Genetics.
Gregor Johann Mendel (July 20, 1822 - January 6, 1884) was a scientist and Augustinian friar from Moravia in the former Austrian Empire who gained posthumous fame as the founder of the new science of genetics. Mendel demonstrated that the inheritance of certain traits in pea plants follows particular patterns, now referred to as the laws of Mendelian inheritance. Because of this discovery, Google wanted people to remember who he is, what he did for science and medicine today and simply appreciate his contribution to the world.
He died on January 6, 1884 at the age of 61 in Brno, Moravia, Austria-Hungary.
The logo is obviously a bunch of peas forming the Google logo, but added to it are the scientific notations. The annotations of G and Y on the peapod logo reflect this idea of traits, with the connecting lines illustrating the continuance of certain traits through the successive generation of plant.
Engadget notes that he famously said "mien Zeit wird schon kommen ("my time will yet come")," arguing that today may be that day. Certainly, it could be your day if you are in Mendel's hometown in the Czech Republic as the Mendel Museum is offering free admission today.
Most likely, you can't make it to the museum, check out this Gregor Mendel Rap, which sums up his core findings pretty succinctly: