Your Inner Fish Chapter 3

Why do we all look different? Scientists try to solve these questions by looking into embryos and messed around with our DNA to see what would  change. Later they discovered the zone of polarizing activity (ZPA), something that instructs cells to produce different things, such as limbs. They named a gene Sonic hedgehog gene, one relating to flying and hypothesized that these genes are capable of making bodies look different. They found a supplier of shark eggs and started performing experiments on shark embryos since they are very distant from humans. And the results matched with the chicken experiments. That was how scientists solved the answer to what makes us look different

Survival of Sickest Chapter 6 review

The Chapter begins with the history of cowpox and how Edward Jenner invented vaccines as he found out that people who caught cowpox were resistant to small pox. Every human starts of from being 1 bacteria and duplicates millions of times to get to our form and shape now. Our DNA consists of 3 billions different nucleotides and every human has 23 chromosomes from each one of their parents, these are called the sex chromosomes adding up to a total of 46. These chromosomes determine our characteristics.

Scientists originally believed that only accidental mutations can possibly cause genetic changes. They thought pandemics followed a trend with sun spots, but they later realized it was because of the antigenic drift that caused our body to be vulnerable. Babara McClintock discovers the "jumping genes" and proposes that genetic changes does not necessarily have to be accidental. She puts an example of how corn's DNA migrates. John Cairns also did an experiment to prove that digestive bacteria can mutate to be not lactose tolerant when only fed lactose. Proving that genetic changes can happen intentionally.

Finally, only 3% of our DNA are used for coding sequences.And scientists found out that the rest are actually a lot of "jumping genes" instead of "junk sequences". Moreover, the Weissmann barrier distinguishes germ cells and somatic cells as changes of somatic cells cannot be passed on.

From Atoms to Traits

1. Explain the significance of Mendel. 

Mendel observed that the pea plants' traits were often similar to those of their parents. Sometimes, however, the pea plants had different traits than their parents. Mendel experimented with thousands of pea plants to understand the process of heredity. Mendel's work formed the foundation of genetics, the scientific study of heredity. Mendel's experiments changed the general
perception of heritable variants from ephemeral
and blendable to discreet entities passed from
parents to offspring, present even though they
are not always visible.

2. Draw the structure of DNA and who discovered this structure. 


James Watson, Francis Crick, Maurice Wilkins


3. Explain each of the five examples of variations that occur to DNA and give an example of each.

Gene copy number - chimpanzees
point mutation - whipped dogs
insertion - pea plants
Inversion - flipping of large segments of DNA within a chromosome
Repitition - repetitions like those that underlie forensic DNA tests


4. What is evo-devo?  A subspecialty ithin
evolutionary biology that has come to be known
as evo-devo Concentrates on studying the effects
of changes in important developmental genes
and the role they play in evolution.
5. Make a connection between human migration and the mutation of lactose intolerance.

Lactose-tolerant population started with a little population then later  the populations have differ-
ent mutations in the key region-a striking ex-
ample of the repeated evolution of a similar trait
by independent changes affecting one gene.

Unit Test 2

Today we took the second unit test, I thought it was slightly harder than the first one that we did because of the enzyme part that I wasn't really sure about and there were some questions that I didn't really understand very well. But overall I am confident that I did okay.

Founder Mutation

Founder mutations are a special class of genetic mutations embedded in DNA and are identical in people who have the same mutation. Moreover, the length of the stretch allows us to determine the age of the founder mutation. These founder mutations are not necessarily bad, they can be beneficial as they may be recessive on carriers and thus helping them in different ways, for example, a mutation of sickle cell can allow a carrier to survive malaria better. Also, finding out the origins of the mutations helps us have a better understanding in how our ancestors migrated when they moved out of Africa as we can trace the founder mutation and see a pattern of mutations in different locations. As the PTC mutation confirms the anthropological and archaeological evidence that the original population of modern humans lived in Africa since all non- tasters of the PTC supposed have the same ancestor and it seven of those genes exist in sub- Saharan Africa. It also confirms that every human are indeed members of a single family as we share the inheritance of our genome. Overall, founder mutations is a great way for us to reveal the truth of where we came from and how we arrived at our modern locations.

GENESS

Today in class we did another activity in which we run around and pretend to mate with each other to see whether the trend that Hardy Weinberg proposed was correct,that p and q should both be around 0.5. Hardy Weinberg suggested that the amount of recessive and dominant genes can be represented by p^2+2pq+q^2 = . So we were assigned with AaAa genes from the beginning with A as the dominant gene and a as recessive, and we pick off random cards from another classmate when "mating". In the end we got answers pretty close to 0.5 and 0.5 we got something like 0.6 and 0.4 but then again we didnt have a large enough population as Hardy would suggest, so I guess it was good enough.

WANNA LOOK HOT?

I've always wondered why do people look attractive, what is it about their face. Today is parents day and before the class we had readings that explain studies that basically say the more symmetrical your face is the more attractive you are, and it also brings up other theories such as being more average is more attractive. And one of the most important ideas is that no matter male or female, we as human beings are attracted to faces that are more feminized because unlike other creatures we bring in emotions when it comes to mating and studies have found that masculine faces are more intimidating and scares other humans away. So in class we had an activity which we are given slides of different pictures of a same person, one feminized and the other masculinized and we had to record the ones that we thought were more attractive. And what I got was 18/20 feminized faces, I guess I really do like girls.

Mating TIGERS !!!

Today in class we did an activity in which we pretend tigers are mating randomly in a dark forest. We put different color beads in two different paper bags and have on color represent the dominant gene and the other represent the recessive gene, and in our specific lab having both genes as recessive will cause the organism to die because of a disease. Slowly, we take out most of the recessive gene, but then we realize that there will always be 1 recessive gene in the pool of tigers in the end. Then if these group of tigers go mate with other tigers from other places that probably has the same recessive gene, then the recessive gene will reproduce again.