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Genetics Help

dismo

Posted 18 January 2007 - 05:52 PM

can anyone explain how gene mapping works as well as recombinant frequencies. I have my prelim next week and don't get it.
Thanks

sweetchick01

Posted 18 January 2007 - 09:35 PM

QUOTE(dismo @ Jan 18 2007, 05:52 PM) View Post
can anyone explain how gene mapping works as well as recombinant frequencies. I have my prelim next week and don't get it.
Thanks


ok i'll give this a try...

This is ususally when talking about linked genes and is caused by chiasmata. Gene mapping is used to find out the order in which the genes which can be worked out by recombination frequencies. The closer the genes are the higher the value of COV(crossover value). If you want to create your own map you need the COV values so the 2 are linked.

Example

Genes Percentage Recombination
M and O 10
N and O 27
N and P 12
M and P 29

your map would be OMPN
1)start with 2 with biggest distance between them [M and P]
2)use one with smallest distance[O can be before M or between M and P]
3)then the next smallest [again N can be before P or between M and P]
4)connect up values for N and O
this all takes a little trial and error (and maths)

Have you seen the past paper questions on this? try some of them if you have a copy.

Hope this helps...and answers your question...

sweety

dismo

Posted 19 January 2007 - 08:59 PM

Thanks, that really helps!

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