February 27, 2011

February 27, 2011

Hello everyone!  I turn 35 years old today - I've entered a new age demographic and I can be president.  I don't really think I'm too interested in either one to be honest! 

Events of the Past Week

Tuesday - Students were introduced to traits carried on the X chromosome called sex-linked (or X-linked) traits.  They are expected to know that red-green colorblindness, hemophilia, and Duchenne muscular dystrophy are all carried on the X chromosome, and that males are much more likely to get these traits than females.  Not only that, but males with X-linked traits must have inherited them from their mother because their father gives them a Y chromosome, so does not give them any genes at all for X-linked traits! 

After the introduction to these traits, all the groups finished their last day of counting flies from the first generation of offspring.  Problems 1-8 were assigned as homework from Problem Set 3.

Wednesday - I introduced pedigrees to the students today.  Everyone seemed to do a good job of grasping the concept of looking at pedigrees to determine how a trait is inherited, and figuring out what genes each individual in the pedigree must have for one trait.  We also looked at how hemophilia was passed from Queen Victoria (who was a carrier for the disease) on to her offspring, then to the royal houses of Spain, Prussia, and Russia.  The spread to the Russian Royal family eventually led to the Russian Revolution and the rise of communism.  As I told your children, it's all about biology!  For homework, numbers 9 and 10 were assigned in Problem Set 3

Thursday - We listened to the song "I'm My Own Grandpa" by Ray Stevens, and the students attempted to draw a pedigree of the family described in the song.  It was not easy!  Afterwards we removed all of the parents from the vials for our second generation of flies, as their offspring will be emerging from their pupae soon!  Then we looked at the answer key for Problem Set 3 so the students could grade their own papers and ask questions about what they got wrong.  Finally, the worksheet "Human Pedigree Genetics" was assigned for homework.

Friday - We took our first genetics quiz on Friday.  It consisted of 15 multiple choice questions and 1 short answer problem.  All of the concepts we had covered to that point were included on the quiz.  Afterwards, students read the article "Go Ahead, Kiss Your Cousin (Heck marry her if you want to)" from Scientific American.

Upcoming Events

Monday - We will be checking to see if we need to count flies from the second generation yet.  If so, we will probably spend most of the period counting, as this generation will take a little bit longer to count than the previous generation.  If not, then I will introduce the students to the inheritance of blood types, which exhibit both multiple alleles and codominance.  I won't explain that here, but it might be a good idea to ask your children to try to explain it to you.  You might also ask them to explain the difference between codominance and incomplete dominance.  If they can't, please encourage them to ask those questions in class or come see me for some extra help.  I will also introduce the Hardy-Weinberg Theorem to the students.  Problem Set 4 will be assigned for homework on Monday if I introduce those topics rather than have the students count flies.  If we count flies, then there will be no homework on Monday.

Tuesday (Late Start Day) - We will either be counting flies or doing some practice Hardy-Weinberg problems Tuesday.  My best guess is that this is the first day we will be counting flies for the second generation, however.

Wednesday - The students will be introduced to the concept of having two genes linked together on the same chromosome, which will change the expected ratios of offspring with different traits.  We will also have some time to count flies.  Problem Set 5 will be assigned for homework.

Thursday - Genetics Quiz #2 will be given on Thursday if everything goes according to plan on the first 3 days of the week.  If fly counting pushes us back, then the quiz will be either Friday or Monday.  We may need to count flies on Thursday.

Friday - If the students have already taken the quiz, then they will be introduced to nondisjunction, which is an error that occurs during meiosis leading to an extra chromosome being inherited by the offspring.  This can lead to many disorders, such as Down's Syndrome, Patau Syndrome, and Edward's Syndrome, to name a few.  There will also be time to count flies.

Graba Geek of the Week

The first ever Graba Geek of the Week goes to Zach Hebebrand, who knew without being told that Charles Darwin's birthday was on February 12th, the same day as Abraham Lincoln's.  Very impressive!  Zach has also been doing very well with our genetics problems so far. 

Have a great week everyone.

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