"From Atoms to Traits"

1. The significance of Gregor Mendel is that through his experiments with peas in the 1850's and 1860's, he proved that variants in species are inheritable. Mendel also proved that genetic variants do not "blend" away in future generations, they reappear. This is evidence for Darwin's theory of evolution through natural selection.  

2.  James Watson and Francis Crick discovered the double helix structure for DNA.

 

3. Homopolymers are stretches of DNA with eight or more identical letters in a row are prone to copying errors during DNA replication. An example of homopolymers is microsatellites consists sequences of two or more nucleotides in a row.  The second variation in DNA is when the bases change from G to A. An example of this is in peas when the variation occurs it shortens growth.  The third variation is “jumping” elements which changes gene activity patterns by creating new regulatory sequences. An example is the wrinkly seeds of peas.  The fourth variation is the change in regulatory genes that regulate cell division. An example is the differences between the maize plant and the tesinte plant. The fifth variation is change in pigment cells. An example is the change in human skin color.

4. Evo-devo is studying the effect of changes in important developmental genes and the role they play in evolution.

5. Migration and human reliance on other animal’s milk as a source of food was a result of the mutant form of the lactase gene which is only active in infants in other mammals, continues to be active in human populations they depend on milk as nutrition.