122Chapter 4 •Eukaryote Chromosome Mapping by RecombinationInputTesterPOutputMeioticdiploid (F1)A/a . B/bA . Ba . bn2nA/A . B/Ba/a . b/b. Meiosis. . . . MeiosisFertilizationParental-typegameteParental-typegameteRecombinantgameteRecombinantgameteParental type++++Progeny (2)Parental typeRecombinantRecombinant±. . . . . . . . Figure 4-7 Detection ofrecombination in diploidorganisms. Recombinantproducts of a diploidmeiosis are most readilydetected in a cross of aheterozygote and arecessive tester. Note thatFigure 4-6 is repeated aspart of this diagram.in Figure 4-8. Let’s reconstruct a standard Mendeliananalysis to illustrate how recombinants are produced:PA/A;B/B±a/a;b/bGametesA;Ba;bF1A/a;B/bTestcrossA/a;B/b±a/a;b/bF1dihybridTesterProgenyA/a;B/ba/a;b/bA/a;b/brecombinanta/a;B/brecombinantThe last two genotypes must be recombinant becausethey were formed from gametes of the dihybrid (output)that differed from the gametes that formed the F1(input). Note that the frequency of recombinants from
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This note was uploaded on 01/10/2011 for the course BIOL BIOL taught by Professor Johnson during the Spring '08 term at Aberystwyth University.