IUBio

Multi-Point Mapping conundrum... ACEdb defies mendels laws :-)

Mark Wilkinson markw at cheerful.com
Wed Nov 17 12:06:27 EST 1999


I am a bit confused about how ACEdb uses the data it gets from a
Multi-point data entry...

So... you have to enter a certain physical location for each marker,
ya?  fair enough.  But you are also allowed to enter two-point and
multi-point data for any number of markers spanning that region, and (if
I understand correctly) these data are used by the GMap functions to do
the probability calculations and the 'recalculate-map' functions... or
am I up the creek on this one already?

But... but but but... my Genetics professor's voice is ringing in my
head at this point saying, "you need to put your recombinants over the
TOTAL number of individuals to generate a map distance... dummy!!"

So... how does ACEdb know how to calculate a map distace when it doesn't
know the total number of individuals??

eg. A_not_B:   W 20 X 10 Y 5 Z

in this example how does ACE know if the W-X interval contained 20
recombinants out of 200, 2000, or 2 billion individuals scored??  Surely
this is important?  or??

what am I missing here?

Oh... and while we are on the subject, a quick clarification.  the
numbers in the intervals - they are number of recombinants, right?  Not
numbers of NON-recombinants...  (i.e. it is a bit confusing whether the
number in the intervals refers to W_not_X   versus W_and_X)

Best wishes to you all!  Any advice appreciated!

Mark







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