From Atoms to Traits

1. George Mendel led a series of of breeding experiments during the 1850's-60's with different pea plants that showed morphological differences. It showed how some differences in pea plants stem lengths, seed smoothness, and many other differences. Mendel's experiment showed that heritable traits were passed from parents to offspring even though they weren't always visible. This led to the discovery that this pattern is mirrored within the chromosomes in a cell nucleus.

2. James D. Watson and Francis Crick discovered that DNA is made of two stranded helix held together with pairing of the four chemical bases: adenine, cytosine, guanine, and thymine which are passed form parent to offspring. It looks like 

3.

1. Point Mutation- A single base pair is changed changing the traits of a species. An example are whippet dogs. The simple change in one base pair changes the muscle growth of the dog which changes its main skills and abilities.
2. Insertion- Additional base pairs to genes changes the traits of a species. An additional 800 base pair is added to the genes of peas to make them wrinkled rather than smooth.
3. Gene Copy Number- Duplicating by copying errors in genes can cause differences as well as variations between the same species. Chimpanzees carry one gene for the starch digesting enzyme whereas humans can carry up to 10.
4. Duplication- Strands repeating the same base pair eight or more times are called homopolymers which are prone to copying errors. In pigs two additional C-G pairs cause light colored coats, but by duplicating mistakes the pig can get dark patches.
5. Regulatory Changes- Mutations that control the genes location can transform the formation of an organism. Changes in the region of a single gene cause the difference between the bushy teosinte plant and the tall modern cornstalk.

4. Evo-devo studies the evolutionary development of organisms or the study of influential developmental genes and their role in evolution.

5. As we already know, life started in Africa. Since life started in Africa and it is shown that the gene that allows people to produce lactase is common in Saudi Arabia we can deduce that humans were originally made with the ability to produce lactase throughout their life. As modern day comes to be we see that more and more people have lost this gene. From this information we can only conclude that somewhere after the human migration from Africa people began developing a different gene that doesn't allow them to produce lactase as an adult. This gene has been passed on for centuries through travel as has now made the common person unable to produce lactase as an adult.