Slide 1Mendelian ratiosPartial or Incomplete DominanceMENDELIAN GENETICSJanuary 28, 2015Mendelian ratios•Monohybrid: study single pair of alleles•3:1 = phenotypic ratio•1:2:1 = genotypic ratio•1:1 alleles at one locus segregate equally (testcross)•Dihybrid: study of two pair of alleles•9:3:3:1 = phenotypic = both dihybrid gametes independently assort•1:2:1:2:4:2:1:2:1 genotypic ratio•1:1:1:1 one dihybrid gamete independently assorts (testcross)Partial or Incomplete Dominance •Dominance that occurs in heterozygotes•One dominant allele is only partially expressed and this determined by a threshold effect•1:2:1 genotypic ratio
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