37 - MCB 142 Professor Georjana Barnes Lecture 37 ASUC Lecture Notes Online(formerly Black Lightning is the only authorized note-taking service at

Info iconThis preview shows pages 1–2. Sign up to view the full content.

View Full Document Right Arrow Icon
11/21/07 Lecture 37 ASUC Lecture Notes Online (formerly Black Lightning) is the only authorized note-taking service at UC Berkeley. Please do not share, copy or illegally distribute these notes. Our non-profit, student-run program depends on your individual subscription for its continued existence. These notes are copyrighted by the University of California and are for your personal use only. Sharing or copying these notes is illegal and could end note taking for this course ANNOUNCEMENTS You can turn Professor Rokhsar’s exam in for regrading this week or next Monday. The location of the room where you’ll be taking the final exam has been changed and the change is TBA. The other thing is that I’ve been getting a lot of questions regarding what’ll be on the exam – that is, material from lecture or from the book. So to remind you, everything that I’m covering I’ve taken out of the book. Go to the website and see the reading list. You need to do the reading, especially in chapter 18 (I think) that we’re finishing today, which has been a long chapter. We’re going to be starting chapter 19 next week. So the good news is you have this whole weekend to finish chapter 18 and do problems. REVIEW Picking up where we left off last time, we were talking about how to silence genes through chromatin structure (the nucleosomes cause the DNA to wrap around so it’s not exposed to transcription factors in eukaryotes). Then we moved from two silencing mechanisms – hypermethylation and special silencing complexes (the example in yeast of SIR complexes). Then we went on to consider the phenomenon of genomic imprinting where now it matters if the gene has come to the offspring through the father or through the mother. Imprinting as you remember was discovered some 20 years ago when scientists were manipulating haploid nuclei from mouse eggs and sperm. They found that when they took nucleus out of the egg and put into that nucleus two haploid nuclei from mother, they found that there were no viable offspring. In other words, the resulting egg did not develop. It was counter to what you would expect based on what Mendel says, where the allele doesn’t matter if come from mother or father. But in this case it did matter. They only got viable offspring if they took haploid nuclei from a female mouse and haploid nuclei from a male mouse. The only difference between those two nuclei were that they came from different parents. So this meant something was wrong with our idea of the passing on of genetic material; what was wrong was that we didn’t know of something called genomic imprinting. So the human geneticists, where we left it last time, read about these mouse experiments. They thought: does this explain human genetic diseases that are not completely penetrable? That is, they knew of some families with a disease, but where there were not enough individuals showing it as predicted. So in those cases, they evoked partial penetrance of an allele as an explanation. But in
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Image of page 2
This is the end of the preview. Sign up to access the rest of the document.

This note was uploaded on 04/04/2008 for the course MCB 142 taught by Professor Slatkin during the Fall '08 term at University of California, Berkeley.

Page1 / 5

37 - MCB 142 Professor Georjana Barnes Lecture 37 ASUC Lecture Notes Online(formerly Black Lightning is the only authorized note-taking service at

This preview shows document pages 1 - 2. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online