RI vs. DH population

Ed Coe ed at teosinte.agron.missouri.edu
Thu Jul 2 21:27:18 EST 1998


Dear Brian:
Agreeing with you, unequivocally.
RI lines are, at the limit, twice as informative as single meiotic
strands (doubled haploids or backcross individuals).
F2 individuals are also twice, but for different reasons (because F2
individuals each contain two meiotic products that are fully genotypable
for tightly linked loci).
For RI lines, my reasoning has been as follows:
In F2 individuals, upon selfing toward RI lines, the two strands again
undergo reduction and lose half of the recombination events (2 potential
per region), but half of the regions (at a small limit) were
heterozygous and can experience recombination, while half of the
recombinations become fixed, etc., for each generation.  Thus, 1 + 1/2 +
1/4 ... = 2.
Ed Coe


Date: Thu, 02 Jul 1998 14:13:26 -0700
From: Brian Nguyen <bnguyen at ps.com>
To: nobody at net.bio.net
Subject: RI vs. DH population
Newsgroups: bionet.genome.arabidopsis
Dear All,
If you had to map two tightly linked loci (less than 0.1 map units
apart)and had both  recombinant inbred (RI) and doubled haploid (DH)
populations of the same size at your disposal, would there be an
advantage of using one over the other?  I believe that if the size of
both mapping populations is the SAME, then the RI lines would be better
suited for this task.  This is because a greater number of meioses have
occured in this population thereby increasing the chance of recovering a

recombinational event between the two tightly linked loci. My colleagues

believe that this is not a valid point and there is no advantage of
using one over the other for this task.
Please post all responses on this NG
Cheers!
Brian




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