Laws of Genetics

In 1860, Gregor Mendel, an obscure monk cultivated peas in his monastery garden.

Being of a curious sort, he wondered about how the colors and sizes of the peas were transmitted from generation to generation.

Would the crossing of a blue flower and a red flower give him a purple flower?

Blue Flower is Dominant

Red Flower is Recessive

The next generation yields:

One Dominant Blue carries two blue genes BB
Two Crossed  Blues Carries one blue and one red gene BR
One Recessive Red Carries two red genes RR

Yikes!  There is no purple flower!

From the results of thousands of experiments Gregor worked out the laws of Genetics. BB+2BR+RR

He worked out the "mathematics of inheritance" and postulated that these characteristics were carried in tiny particles that did not change with age or mix with one another.

It would be a hundred years (1953), before the particles that Mendel proposed would be found.

Those particles of inheritance are
the "molecules of DNA".

The nature of the individual is constant over time. The DNA remains the same over the lifetime of the individual.

It is DNA that identifies each and every species!