Reflection - Cracking the Code of Life Part II

          We finished this movie in class today.  It showed more diseases that can be passed on through heredity like cancer.  One thing I really liked about this movie is that it showed a variety of things.  It hopped back and forth from showing us stories about people with disease caused by their genes, and the two competing teams of scientists trying to be the first ones to map someone´s entire DNA structure.  The movies made me more aware of the role genetics plays in our lives, and how there are some things we can´t escape because it´s in our DNA.  Something I found ironic was the fact that in my previous post, I had made connections between Cracking the Code of Life and Gattaca, and the documentary had clips of Gattaca in it, and talked about how our future might very well turn into one just like in the world of Gattaca.  All in all, I thought that Cracking the Code of Life was a good movie full of information for people who want to learn about genetics.

Reflection on Cracking the Code of Life Movie

          So far, this movie has taught me a lot about genetics, and since it's pretty interesting, what I learn sticks in my brain.  One really important thing that I learned from this movie is that even just one wrong letter in your DNA can decide whether you will grow up to have schizophrenia, a deathly disease, cancer, or some other horrible illness.  Just one out of all the millions of A's, C's, G's, and T's in your DNA can determine how your life will end.  One example of a rare but horrible disease that is caused by two parents passing two of the same recessive alleles to their child was showed in the movie.  One pair of parents each had the Tay-Sachs gene in their bodies.  Both of them passed this gene on into their child, and their child developed this disease.  The father's identical twin brother had just resolved that he had to be his brother's rock and support him, when he discovered that his child, too, had Tay-Sachs.  It was such a sad story because Tay-Sachs is such a rare disease.  Even if one parent has the allele for it, they won't be able to pass it on so that it harms their child, and if both parents have it, there is only a 25% chance of their kids getting the disease. 
          The movie then discussed how scientists may be able to map one person's entire DNA, and tell them which diseases they may develop, how long they may live...everything about their future.  Personally, I think this is a great idea if you are only doing it to stop yourself from passing illnesses on to future generations.  However, I feel that if we have this ability to map out peoples' lives in our hands, our world will become kind of like the one in the movie GATTACA.  You will only be able to do a certain job because of the DNA you have, and you won't be allowed to do other things because of your genes.  I don't think that this would be such a great thing, and I hope that if our planet does become like GATTACA, it doesn't happen in my lifetime.

Current Events: Twins and Heredity

          National Geographic is talking about studies on twins and how they can help scientists discover exactly how much of an influence heredity has on our lives.  One very interesting story featured in the article was about two twins who were separated at birth.  Coincidentally, both families who adopted each twin named their kids Jim.  The two twins were reunited when they were 39, and they realized that, even when they were separate, they had led similar lifestyles.  Both Jims had married and divorced women called Linda, and then remarried to women called Betty.  They had named their sons James Allan and James Alan, and they had both taken their families on vacation to the same beach in Florida.  Both men had had dogs named Toy, and each had been part-time sheriffs, dabbled in carpentry, smoked the same kinds of cigarettes, and drank the same kinds of beer.
          I thought that this section in the article was very interesting, because it helps show exactly what a strong pull genetics has in our lives.  When I read it, I was shocked that the two Jims even married wives with the same names.  How does liking different names have anything to do with genetics?  But how can it be a coincidence that so many of the names in the two Jims' lives were the same?  This article was also very thought provoking, because it also said that even though they had been raised in different families, both had similar IQ scores.  Later in the article, it stated that 75% of IQ differences was because of genes, and not the environment around the people.  I don't really like that idea, because they are trying to say that how smart you are depends on what you inherited from your parents.  I think that your surroundings and how hard you work also has an influence on your IQ, and I just don't really think it's fair that you inherit your smarts.

Resource:  National Geographic Magazine for January 2012, page 54

Mendel's Pea Experiment

         Gregor Mendel was a monk who lived in what we now know as Czech Republic.  He enjoyed gardening, and one day he became curious about the fact that some pea plants were tall and others were short; some were yellow, and some were green etc.  Mendel decided to check this out, so he forced a tall pea plant and a short pea plant to mate with each other by collecting the pollen from one and placing it in the pistil of the other.  He made sure that neither plant mated with its own type.  The pea plants produced from that experiment were tall - not of medium height like you would expect to get by mixing a tall and a short plant, but tall.  After many more experiments, Mendel then proceeded to mate the offspring of the original pea plants with each other.  Curiously, three out of four pea plants were tall, but one was short. 
          From these experiments, Mendel became the first investigator of genetics.  The parent plants were both purebred short and tall pea plants.  When they were mated to produce F1 offspring, each parent plant passed on one allele.  (An allele is a form of a gene that changes is in charge of changing only one aspect of a trait.)  The tall plant passed on an allele for being tall, and the short one passed on an allele for being short.  If the dominant or tall allele is represented by a capital T and the short or recessive allele is represented by a lowercase t, then the alleles for the F1 offspring looked like Tt.  What Mendel began to discover was that a recessive allele will only be visible in an organism if it is the only allele for that trait present.  If there is one tall and one short allele, then the plant will be tall.  If there are two tall alleles, then the plant will be tall.  The only way the plant will be tall is if it has two short alleles.  This is why none of the F1 offspring were able to be short, because they always had one short and one tall allele.  However, when Mendel mated F1 offspring with each other to make F2 offspring, he noticed something strange:  approximately 1 in every 4 pea plants created by two F1 offspring were short.  This was because, although all the F1 offspring were tall, they each had one short and one tall allele.  When two of them were mated, there was a small possibility that, out of Tt and Tt alleles, a seed would be generated that would be tt. 
          The experiment we did was that we had a bowl full of yellow and black balls to represent peas.  The ratio of yellow to black peas was uneven, and there were many more yellow peas than black ones.  We took turns pulling out four "peas" from the bowl and recorded our data.  We did this 20 times.  Each time, we wrote down how many yellow and how many black balls we pulled out of the bowl, and then we averaged our results.  In the end, we pulled out 2.85 yellow peas and 1.15 black peas, which averages down to three yellow and one black pea.  Mendel, on the other hand, would have had to do this experiment MANY more times, since he did not know any of the things we do now about genetics.  Mendel probably had to plant 50 to 100 pea plants to be sure of his data.

Reflection on Gattaca

          I really enjoyed this movie.  I thought that it was really interesting how everyone was chemically made to be immune to diseases, live long lives, and have overall good bodies physically.  Also, scientists were able to get rid of traits such as attention deficit disorders and anger management problems.  However, I thought it was really unfair that people who didn't have great genes were not allowed to do things like fly into space, but that others who were genetically modified could take good jobs just by giving in a urine sample.  Even if someone had a really good brain, they would not be permitted to do the really important stuff.  If you had not been made in a test tube, then you were not expected to be great physically, either.  No matter how hard you trained, everyone would expect you to lose in sports because of your genes.  I also thought that it was really interesting that scientists were able to figure out one person's whole life at birth.  The main character was told that he had a 99% chance of heart problems, an expected life span of 30.2 years, and many other things the second after he was born.  From then on, people could tell everything about you just by taking a urine, hair, blood, or skin sample from your body.  This whole idea of genetics and DNA was very, very interesting and overall, I enjoyed the movie.  Even though it's fictional, I learned a lot about how DNA is almost everything about you from the film.