A (virtual) place for BIOL335 (2008) people to ask questions, answer questions, make requests, comment, wonder, discuss, complain and rejoice.
Friday, February 29, 2008
Sequencing of an entire genome
6 comments:
Anonymous
said...
Hi Pam!
I just wanted to say that I felt that Monday's tutorial (March 3) was very useful and helpful doing the extra problems in class together. In my opinion, it was more helpful than the structure of the tutorial the week before or the week that we drew the posters. Thanks!
I was reading about yeast 2 hybrid system...and it states that sometimes yeast 2 hybrids has lots of false positive and false negatives results due to overexpression?, and problems fusion with AD and BD? What would overexpression mean and problems with yeast 2 hybrids mean?
True, the yest 2hyb often gives "falses". If you overexpress a protein, the "surplus" may go bind to DNA sequences or (like in this case) proteins that it does not usually interacts with. So, you would "see" an interaction in the 2 hybrid system, but it would be an artifact of the experimental system, and those two proteins do not actually inetract in "real life".
You may also get "false negatives". Foe example, some proteins cannot bind a protein of interest in the absence of "auxiliary factors" (other proteins), and since these auxiliary factors may not be present in the yeast, they won't produce an interaction in the 2 hyb system, but they may well interact in "real life".
Much of the material found on this blog represents creative work in a tangible form, and is therefore subject to those copyright laws that apply. Unless stated otherwise, the authors of the works posted are myself and the UBC BIOL335 (Spring 2008) students in tutorial sections T53 and T59.
6 comments:
Hi Pam!
I just wanted to say that I felt that Monday's tutorial (March 3) was very useful and helpful doing the extra problems in class together. In my opinion, it was more helpful than the structure of the tutorial the week before or the week that we drew the posters. Thanks!
I do also agree with the above comment. in general I fill that tutorials are not helping me to prepare for exam. thanks!
Hi Pam,
I was reading about yeast 2 hybrid system...and it states that sometimes yeast 2 hybrids has lots of false positive and false negatives results due to overexpression?, and problems fusion with AD and BD?
What would overexpression mean and problems with yeast 2 hybrids mean?
True, the yest 2hyb often gives "falses". If you overexpress a protein, the "surplus" may go bind to DNA sequences or (like in this case) proteins that it does not usually interacts with. So, you would "see" an interaction in the 2 hybrid system, but it would be an artifact of the experimental system, and those two proteins do not actually inetract in "real life".
You may also get "false negatives". Foe example, some proteins cannot bind a protein of interest in the absence of "auxiliary factors" (other proteins), and since these auxiliary factors may not be present in the yeast, they won't produce an interaction in the 2 hyb system, but they may well interact in "real life".
Does this help?
Cheers
Pam
hi pam,
how come this blog is not updated anymore since february?
thanks
That's a good question.
What would you like to find here? Let me know and I'll make sure it's up.
In the meantime, some Q&A from previous terms are coming...
Thanks for you comment.
Pam
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