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Unformatted text preview: pically has red eyes (+). An alternate form of the red eye allele is the purple eyed (pr) phenotype: ALLELIC FORMS FOR EYE COLOR AND WING SHAPE Wild type (normal) red eyes = Pr, pr+ or + normal wing shape = Vg, vg + or + Mutant (defective) purple eyes = pr vestigial (stubby) wing shape = vg March 19, 2012 BIS101001, Spring 2012--Genes and Gene Expression, R.L. Rodriguez 2012 7 Linkage or eye color and wing shape alleles Previously, Mendel showed that a test cross for an F1 expressing 2 traits (dihybrid) produced a 1:1:1:1 ratio. However in the test cross below, Morgan found an exception to Mendel's results. In the example below, the test cross to a homozygous (male) tester, produce the standard 1:1 ratio typical of a monohybrid cross. In other word, the eye color (pr) and wing shape (vg) are acting as one gene or "linked". F1 pr + vg X + pr pr vg tester vg pr pr vg vg pr + vg + 1:1 ratio
March 19, 2012 BIS101001, Spring 2012--Genes and Gene Expression, R.L. Rodriguez 2012 8 Interchromosomal...
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