5_Biol221 Lecture 5 01_27_11

5_Biol221 Lecture 5 01_27_11

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Unformatted text preview: PYM endoreduplicaAon Perazza, D. et al. Genetics 1999;152:461-476 Copyright © 2007 by the Genetics Society of America Additional examples of recessive epistasis. Blood types in humans 38 Co-dominance IA/IA IA/i IB/IB IB/i IAIB i/i 39 Bombay Phenotype 40 Bombay Phenotype An O blood type child can also be born to parents who do not have the O allele if a recessive form of the allele for the H antigen also is inherited from both parents. 41 Bombay Phenotype •The H antigen is a precursor to the A and B antigens. •The A and B alleles must be present to produce the A and B enzyme that modifies the H antigen to become the A or B antigen. •If only recessive alleles for the H antigen are inherited (hh), as is the case for this pedigree the H antigen will not be produced. •Subsequently, the A and B antigens also will not be produced. 42 Bombay Phenotype Bombay Phenotype 43 Bombay Phenotype 44 Dominant Epistasis Synthesis of malvidin is controlled by gene K, yet producAon of this pigment can be suppressed by gene D, which is found at completely different locus. In this case, the D allele is dominant to the K allele, so plants with the genotype KkDd will not produce malvidin because of the presence of the D allele. Dominant Epistasis K Malvidin D Synthesis of malvidin is controlled by gene K, yet producAon of this pigment can be suppressed by gene D, which is found at completely different locus. In this case, the D allele is dominant to the K allele, so plants with the genotype KkDd will not produce malvidin because of the presence of the D allele. Dominant Epistasis 12:4 Duplicate Gene Action For this type of pathway a functional enzyme A or B can produce a product from a common precursor. The product gives color to the wheat kernel. Therefore, only one dominant allele at either of the two loci is required to generate the product. Thus, if a pure line wheat plant with a colored kernel (genotype = AABB) is crossed to plant with white kernels (geno...
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This note was uploaded on 01/20/2014 for the course BIOL 221 taught by Professor Gallagher,kimberly during the Spring '13 term at UPenn.

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