On P elements and chapter 17
posted by pam39 at 10:15 AM
Tuesday, July 17, 2007
BIOL335 links
- Your textbook!
- UBC BIOL335 website(updated)
- More than you'll need to know on P elements
- Link to a site on Ac/Ds elements
- Landmark discoveries in molecular biology
- Link to mol.gen. of prokaryotes course at univ. of Arizona
- Lac operon stuff
- Link to a clatech problem set
- Link to another caltech problem set
- Link to Dr. Zimmerman's molbiol-check out their links!
- BIOL334 website
Genetics links
- Your textbook!
- Traditional genetics terms
- Human genetics problem sets (University of Arizona)
- Mixed problem set
- Another problem set (vcu)
- Another problem set (vcu)
- Pam's loppins questions
- Triploid bananas: how does it work?
- BIOL334 website
Previous Posts
- More questions
- On RFLPs, chromosome walking, etc!
- More questions
- markers question
- extra help session
- post-midterm thoughts
- A few answers
- QUESTIONS THAT CAME UP!
- TECHNIQUUES
- ANNOUNCEMENT
3 Comments:
Pam, can you post the solution to Q30? I've tried solving it and looked at the solution manual, but it still doesn't make sense. I can't see how the Anterior (A8 ends) would form on the other side as well. I thought only Posterior ends can form on both sides.
The answer from the solution manual does not make sense to you because it's incorrect!
If you remove the anterior 20% of the cytoplasm from a WT embryo, you are basically removing most of the bcd and hb-m determinants. You will still have enough to make segments A4-A8. However, it won't be a mirror image, because the anterior-most region of the embryo (after removal of the cytoplasm) will still have relatively high levels of bcd+hb-m. This anterior-most region may look similar to a misformed posterior more than to an anterior, but it won't be an A8.
Another thing to keep in mind is that these effects can only be observed in embryos (because the individuals won't survive past the embryonic stage) and in an embryo many things can go wrong at the molecular model with relatively minor visible phenotypes at the macroscopic level. The distinction between an A8 and an A7 segment is, at that stage, pretty subtle, trust me!
Cheers
Pam
P-elements need to have repressors present in order to not jump and they get all the repressors they need from the mother. Once the P-element is in the chromosome it is in there and passed on to future generations. As long as the disruption is in the female it will have consequences for the progeny (?)
With Ds/Ac elements they can jump in and out as long as transposon is present and they will move as long as they have the activator there but it will not be something that will have direct consequences to the future generations as far as F2 is concerned (since they can be crossed with wild type individuals and gain the phenotype back)
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