HELP ME please...ABOUT THIS GENE MAPPING THING

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yahoo12345
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HELP ME please...ABOUT THIS GENE MAPPING THING

Post by yahoo12345 » Sun Jul 08, 2007 2:27 pm

Consider the following example. If on the same chromosome: (a) there was 5% crossing over between genes A and B, 7% crossing over between A and C and 12% crossing over between B and C, draw a section of the chromosome showing the location and map distance apart for the genes A, B and C (b) the percentage crossing over between B and C was not 12% but 2%, draw a section of the chromosome showing the location and map distances apart for the genes A, B and C.

That's the question, but I'm not really sure how to do it. Can someone demonstrate it or any photos?? Please help me. Thanks.

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Post by canalon » Sun Jul 08, 2007 3:02 pm

1 centi morgan: distance between 2 genes who will lead to 1% recombination.
You know the percentage of recombination, so you know the distance between A and B, A and C, and B and C, and it should not be too complicated to draw maps for both situation, it is just pure logic.
Patrick

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any proof. (Ashley Montague)

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Post by yahoo12345 » Mon Jul 09, 2007 2:13 pm

can u please give me a sample to solve the first one?..because it's a lesson my teacher never taught..thanks..HOW COULD I "DRAW A SECTION IN A CHROMOSOME TO DETERMINE THEIR LOCATION..."? PLEASE HELP!

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Post by canalon » Mon Jul 09, 2007 7:01 pm

Draw a line, that is your section of chromosome. Put a mark on it, and name it A. Arbitrarily (and conveniently) define a scale for genetic distance (1 centimorgan= 1centimeter/square/whatever).
Then write on a paper the distances between A and B, A and C, and B and C.
See which locations for the 3 points will match with our measurements (not too hard) and repeat for the second set of distances.
Patrick

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Post by yahoo12345 » Mon Jul 09, 2007 9:49 pm

sir what about the thing they called "map unit"? is it same as centi morgan?

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canalon
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Post by canalon » Tue Jul 10, 2007 5:21 pm

never heard that, but I would suppose so.
Patrick

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Post by siroma » Wed Jul 11, 2007 1:46 am

yahoo12345 wrote:sir what about the thing they called "map unit"? is it same as centi morgan?


That's right.
http://en.wikipedia.org/wiki/Centimorgan

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