DNA Investigation and Journey of a Man

Our class spent our last meeting finishing up the film, "Journey of a Man". The movie basically explains how DNA can be traced through numerous generations by following the Y-chromosome from males in different regions. The movie concluded by saying, every person on earth has some type of relation to our original ancestors, the San people. The San people posses the facial features of every type of race today: Asian, African, and European.

Homework Questions:
1. Darwin believed that when genetics were passed down to offspring, the offspring received a fair balance (50/50) from both the mother and the father. Mendel, however, proved this to be wrong when conducting his cross-breeding experiments using pea plants. His results demonstrated that either the mother or the father's genes were shown up as more dominant in the offspring produced. His work with genetics sparked great interest in the field and was some of the groundwork for later research down the road.

2. Watson Crik and James Watson were the two scientists that discovered DNA's double-helix structure.

3. There are five mutations that can occur in DNA: insertion, copy number, regulatory changes, point mutation, and duplication. An insertion mutation occurs when there is an addition of one or more nucleotide base pairs in a DNA sequence. Insertions vary from one base pair incorrectly inserted in a DNA sequence, to even a section of one chromosome inserted into another. An insertion can lead to genetic disorders depending on the gene in which the insertion occurs. Copy-number variation, which is a type of structural variation, is an alteration of DNA in a genome that results in cells having irregular variation in the amount of copies for sections of DNA. A chain that, for example, could be D-C-B-A, (using correct nucleotide base pairs of course) would turn out as D-C-B-B-A, causing mutations and abnormalities. Regulatory changes occur when DNA mutations are formed in the region of the double helix that controls which traits are passed down. Various forms of the same plant demonstrate this type of mutation, shown by their different heights, colors, physical traits, and sizes. Point mutation is when a certain individual contains a DNA change in the same section of another. So an identical species, such as a horse, could be the same type of breed, yet one is very muscular and large, while the other is slender and less strong. When homopolymers are duplicated incorrectly, the "duplication" mutation occurs. This can cause variations in physical appearances such as dark spots. 

4. Evo-Devo studies changes and variations in developmental genes and how the changes may impact and change a population, and effect evolution. 

5. The enzyme used to break down and digest dairy-based products is called lactase. In younger years, more specially as infants, humans posses this enzyme since it is necessary for development. As they progress into adulthood and are able to find alternate ways of nourishing themselves, this enzyme slowly diminishes and the person may become lactose intolerant. Some people, however, are able to retain this enzyme and are able to produce all the way into adulthood. This is most commonly seen in European people since the DNA mutation originated in the European region. As people began to immigrate out of the region, and began reproducing with very different genetic codes, the mutation slowly began to die out. The more dominant, foreign genes wiped out the ability to produce this enzyme and the mutation now occurs less and less because of this.