Gregor Mendel was the man who cleared up all misunderstandings about genes and its inheritance. His experiments with peas included tall pea stalks, short pea stalks, wrinkled peas, smooth peas, yellow ones, green ones, etc. He found that, when two true-bred peas were crossed, the offspring would look like one or the other, but when the offspring are further crossed, some traits that had been thought to disappear reappeared again. Before, people had thought that offspring were the perfect cross between their parents, i.e. if a brown rabbit mated with a white rabbit, their offspring would be tan. However, with Mendel's pea experiments, it was revealed that the features weren't the perfect cross, but only inherited some features from one parent and some from another.
2. Draw the structure of DNA and who discovered this structure. 
DNA was officially known to be discovered by James Watson and Francis Crick, as they were the ones who proposed the double helix theory, but this is not the complete truth. They had taken a photo from Rosalind Franklin, who, after many years of research, had taken a picture of DNA that showed a double helix. Since Franklin would not give the photo to them, they instead asked her assistant, who unknowingly let them into the lab and let them take the photo.
3. Explain each of the five examples of variations that occur to DNA and give an example of each.
1) Point mutation: substitution of a single letter for another at a particular position in the polymer. For example, in whippet dogs, a single base pair change makes the difference between a slender silhouette and the hulking animal. The mutation inactivates the gene for a signaling molecule that regulates muscle growth. In animals with both copies of the gen mutated, muscle growth is uncontrolled for lack of “stop “ signal. When only one copy of the gene is disabled, the dogs are moderately more muscular and prized as racers.
2) Duplication of new letters. Sequences containing the same base pair repeated eight or more times, known as homopolymers, are highly prone to copying errors. For example, in pigs, the gain of two additional C-G pairs in such a sequence inactivates a gene for a signal receptor in pigment cells producing light-colored coats. On the other hand, copying mistakes within individual cells may also cause the duplicated sequence to lose bases, restoring the gene’s function and producing dark patches on the body.
3) Gene copy number. Entire gens can be duplicated by copying errors during cell division, leading to differences between species and to variation among members of the same species. The genome of chimpanzees, which eat green plants, normally contains just a single gene of the starch-digesting enzyme salivary amylase, whereas humans can carry up to 10 copies of the gene.
4) Insertion of new letters. For example, in pea plants, an 800-base-pair sequence inserted into a gene produces peas that are wrinkled rather then smooth. The intruding DNA element disables a gene necessary for starch synthesis, altering the peas’ sugar and water content. Such mobile elements are seen in the genomes of most multicellular organisms, including humans.
5) Regulatory changes. Mutations in the DNA that controls when and where genes are activates can produce profound trait changes by altering the formation of entire body parts during the organism’s development. Changes in the regulatory regions of a single gene that controls patterns of cell division during stem development account for much of the shape difference between the bushy teostinte plant and its descendent, the tall modern cornstalk.
4. What is evo-devo?
It is a subspecialty within evolution that concentrates on studying the effects of changes in important developmental genes and what role they play in evolution.
5. Make a connection between human migration and the mutation of lactose intolerance.
Lactase, an enzyme produced in the intestines, helps infants and children to digest lactose in milk. However, this enzyme is only in children, so adults usually lose the ability to digest lactose-- only a small number of them can still digest it. In 2002, however, it was discovered that in East African and Saudi Arabian populations, who usually herd milk-producing animals, have the trait of lactose tolerance risen slowly but surely many times in the past 9,000 years. Therefore, as people from Africa started migrating to different areas 50,000 years ago, the trait of lactose tolerance was passed down through the Y chromosome, which is why it is traced in Europe, Saudi Arabia, and East Africa.
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