DNA Extraction Lab

Below is the slide show Sidney and I made on Google Docs. It just briefly goes over what we did.
Check it out :)

Genetics...phenotype...genotype...

More than recently ago, we did an activity in class. We made babies. (Nonexistent babies of course.) Each of us had a partner and we conducted an activity to create a child. Later, we drew pictures of our "children" and they were proudly posted on the wall of Mr. Ludwig's classroom. This activity, I believe was done to teach us about genotype and phenotype. Both very important key words when talking about genetics. I'll start off by telling you a little bit about the activity we conducted in class...
          After we had been paired up in partners Alii and I got right down to making our baby. The way the activity worked was we had a list of different features...eyes, mouth, nose, ears, freckles, no freckles, hair color, etc. etc. We flipped coins and used pencil and paper to decide what our baby's genotype would be. I was the daddy (haha) and Alii was the mother. After the genotype was decided this helped us to know what our baby was gonna look like. Which is the phenotype.

         So these traits-eyes, mouth, hair color, etc... is controlled by two alleles. There is the dominant allele and the recessive allele. The dominant allele is referred to this way because of its ability to mask the expression of the other allele. A dominant allele is expressed with a capital letter. The recessive allele is identified with the same letter but in a lower case form. Two identical alleles, for example- TT. (Which is two alleles for tallness in plants.) are homozygous. This means that if there were two parent plants that were homozygous all the gametes produced by these parents would contain alleles for tallness (T). And all of the gametes produced by shorter plant parents would contain alleles for shortness (t). So let's say there was cross-pollination between two plants. Then this new generation would have one allele for tallness and one for shortness (Tt) Because they had two different alleles they are considered heterozygous. Even though these plants had one of each type of allele, they were all tall because (T) was the expressed allele. This makes it dominant.
         This brings us back to genotype and phenotype. Genotype refers to the alleles an individual receives at fertilization. Phenotype refers to the physical appearance of the individual. For example- a person with Genotype TT (homozygous dominant) would have the phenotype of being tall. A person with the genotype tt (homozygous recessive) would have the phenotype of being short.
           In the activity we flipped the coins to decide which allele we would give to the child...it works sort of differently in real life...but you get the point. :)
So there you go! A kind of brief overview on genetics. And how genotype and phenotype fit into all of it.

In Sickness and in Health...Case Study/Greg & Olga

This is the Pedigree that Sidney and I created for Greg and Olga. Greg and Olga are labeled. And you can see their families history.

So Im taking a risk here...the way I understand it, as long as I can prove I understood this whole "assignment" we won't have a problem. Well, obviously the easy way to do it would be to answer the questions provided on the site and show that I was indeed paying attention to what I was reading. BUT as much as I love to answer questions, I am going to just write. And describe what the heck genetic counseling is and how it applies to our friends Greg and Olga. So here we go! :)

          Let's start off with why Greg and Olga came to a genetic counselor in the first place. Greg and Olga are concerned. They want to start a family but each of them have some worries about their families medical histories. Hemophilia A is present in both of their histories and they knew it could be inherited, and they were concerned about passing it on if they had children of their own. Also, several of Greg's relatives suffered from (MD) Myotonic Dystrophy. Knowing that MD runs in families, G & O also had some concerns that they could pass that on as well.

          First we will address the worries over the possibility of Greg being an MD carrier. MD is an autosomal dominant disease. MD does not skip generations. Greg's mother has two siblings that have MD. But there is no chance that his mother has the disease. Neither Greg or his mother could not be carriers of the gene because if they were they would be sufferers of the disease. The possibility of G& O's kids inheriting MD is ZERO. Because neither of Greg's or Olga's parents had the disease, G & O can't be carriers of the gene themselves. That means they can't pass it on to their kids themselves.

        Now when G & O came into the office they also had a couple concerns about diseases that aren't as easy to weed out, Cystic Fibrosis for example. Now CF is one common RECESSIVE TRAIT. A recessive trait can skip generations. Recessive traits (this is very important) are equally likely top affect both males and females. Consanguinity is also included in here somewhere. Consanguinity is the matings between two related individuals. Consanguinity is important when talking about Recessive traits because two people who are consanguineous they have a very good chance of having similar genotype...example, recessive traits.


             If you look at G & O's pedigree we can see that Hemophilia A, Greg & Olga's main concern, is only present in males and it appears rarely. This is a very good indication that Hemophilia A is an X-linked gene. X-linked genes mostly appear in males because the mutated gene is on the X-chromosome. Males only have one X-chromosome. Unlike girls, who have two X-chromosomes. This means if a girl had a mutated gene on the X-chromosome her second "good" X-chromosome could cover it up. If G & O were to have a boy there isn't any chance that Greg could ever pass on the disease at all. For G & O to have a son Greg would have to pass on a Y-chromosome which is not affected by the disease. Because the disease effects the X-chromosome and Greg does not suffer from it there is no possibility that he has the disease. This means he could not pass it on through the X-chromosome he would give a daughter. Looking back at Olga's family history we can see that her mother and grandmother were both carriers. This means there is a chance that she would pass the mutated gene on to her child (male). OR the child could be a carrier as well (male or female)

            This an example of a case that could be brought in to a Genetic Counselor. Genetic Counseling can be very helpful if you have concerns about the child or children you hope to bring into the world.

Here is the website I used to help complete this post:
http://www.sciencecases.org/sickness_and_health/sickness_and_health6.asp