Class Discussion, The Unseen Genome

After discussing the unseen genome in class, your group will be responsible for recording the concepts you identify as “big ideas” (important concepts for understanding the material) on a website created for this purpose.  In order to do this, go to this site: Class Discussion:  The Unseen Genome.  On each sticky, identify your group members by first name only.

“Hey Man…Why are there so many Guy’s at this Party?”

Guest Post by John C

               The continent of Asia is currently undergoing a social upset in the form of imbalanced male-female ratio. Activist Gautam N. Allahbadia explains it in his article by isolating the three cause’s responsible for the issue, namely childbirth that results in maternal death, biased allocation of health care and resources to boys, and female infanticide.  Historically Asia has always been a male oriented society given that there are certain traditions in that part of the world that actually makes it more economically suitable to raise a boy but it seems the ratio of men-women has gotten so out of whack that both India and China are passing legislation that outlaws certain types of sex selection in an effort to change the very cultural fabric of their nations.

This article makes it clear that what we’re learning doesn’t just pertain to lab work and genetic disorders. What’s more this isn’t just an ethical debate about what science is allowed to control as this is happening regardless of the moral implications. Is it the fault of genetic study that there are now 50 million women “missing” from the population of Asia and is it the responsibility of scientists to fix the problem, if so, how?

 

http://www.rotundablue.com/images/pdf/50mwomen.pdf

Regulation of Genetic Expression in Eukaryotes

If you took the time to really understand the pieces of the Lac Operon, you will find some of the terminology and basic ideas of gene expression in eukaryotes to be similar.  There are many differences, however.  For example, while every cell in your body has the same DNA, what DNA is used in which cell varies with cell type and other factors.  The interactive activity below allows you to explore some of the basics of the control of gene expression in eukaryotes.  It then focuses in on one familiar and our best current understanding of it’s control.  The example of interest is Lactase Persistence or the ability to continue digesting lactase past infancy.

Go to this website and explore this activity.  Don’t forget to investigate all of the branches in the activity.  Take notes, because you’ll need the information from this activity for a future assignment.  Be certain to view the gene regulation by transcription control animation when the opportunity arises.  When you are finished with this activity, you can review the animation below.

dna_transcription_regulation-sm

Control of Bacterial Gene Expression , Continued

Today (D-day) you will visit the following website in order to complete a simulated lab and learn more about the Lac Operon.

LAC OPERON LAB

 

Take the time to do the pretest, and all of the activities.  Note that this requires shockwave.  I have had no trouble doing it on my computer.  If you have trouble, try a different browser program (I have done this successfully in FireFox).

 

Because this was a simulated lab, you are not responsible for a formal write up with all of the parts included. Instead, write a discussion as if you have completed the experiments in this simulated lab.  Keep in mind you have learned about both repressible and inducible operons.  Use enough detail to prove to me that you understand this well.  Remember, I don’t make you take a test on this stuff…  show me how well you understand it!  This will be due on Tuesday, before Thanksgiving.  No reason to put it off over the holiday.  You may e-mail it to me, since Tuesday is an A day.

 

The Control of Bacterial Gene Expression

 

The control of bacterial gene expression has been well understood for quite some time.  For the most part, it is simpler than the control of eukaryotic gene expression.  In bacterial genomes, which typically consist of one large circular piece of DNA, groups of genes that function together are often organized in close proximity to one another.  Such organizations of genes are referred to as operons.

Some operons are inducible operons.  These operons require a signal to be turned on (thus they can be induced).

Some operons are repressible operons.  These operons are, by default, turned on.  However, they can be turned off (repressed).

Using the links and documents provided on this page, you will learn about both of these types of operons.  Take notes and organize your thoughts on these topics, because you will be required to write an in depth discussion of bacterial gene expression control for your lab on E day.

Repressible operons

To learn about repressible operons, view the document RepressibleOperons, which includes slides and notes for a presentation on repressible operons.  Once you have completed reading this document, you may watch a summary animation of the operon by visiting Doc Kaiser’s webpage.

 

Inducible operons

To learn about inducible operons, view InducibleOperons.  When you are finished reading this document and taking notes, you may review a portion of the information using the short film below.

LacOperonAdvancedMovHQ

 

The following animations is from Doc Kaiser’s biology web page. Click on these animations to start them

Lac Operon in the presence of lactose

 

 

Here you can see the affect of an activator in the absence of an inducer.

 

 

 

And the effect of an activator protein in the presence of an inducer

 

 

DNA Test Jailed Innocent Man for Murder

David Butler spent the past eight months in jail facing murder charges after his DNA was supposedly found on a murder victim. His DNA was originally put on record after he volunteered to give it to authorities as part of an investigation to the burglary of his mother’s house.

The sample was a partial match and poor quality and experts could not confirm if he was guilty or innocent. Despite this information, he remained in prison. Butler has a rare skin condition causing him to shed flakes of skin and leave larger traces of DNA than the average person. Butler also works as a taxi driver so the transference of money could be the way it migrated to the murder victim.
Although this case occurred in the UK, there are many cases in the states as well. These false cases have gone as far to make the alleged “criminals” as victims of death row. This brings many problems and questions to the table: How big of a role should police play in the decision about the verdict of a DNA test? How much of a match should the DNA be to make somebody “guilty? How much faith should we put into forensic DNA tests?

GMO Lab

On November 7, we began to work on our GMO lab.  In this lab, you extracted DNA from a known GMO sample, from a known wildtype sample, and from a food item of your choice.

On November 8, you will be using PCR to amplify the DNA from each of these samples, and try to determine whether each sample contains a genetic modification.

On November 13, you will run gels to learn about your samples.

The lab handout with methods and conclusion/discussion guidelines can be found here: GMO_student_text

Knockout Organisms and Nobel Prizes

Genetic modifications go far beyond Monsanto corn or soybeans.  One incredible technology used to understand basic genetics is known as “knockout” technology.  This technology is so important, in fact, that Mario Capecchi of the University of Utah was awarded the Nobel Prize in Physiology or Medicine for developing this technique.

You can learn more about Dr. Capecchi’s work by visiting the Genetic Sciences Learning Center at the University of Utah.

 

You may also watch the Mouse Knockout film from HHMI by clicking here:  transgenic_mice-sm.