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Unformatted text preview: Dosage on Enzyme/Product Conc.
Effects Hypothetical Threshold for Normal Phenotype
to conc. of
product 0 Enzyme Concentration
Enzyme A- AB- B02/12/14 A- A+
B- B+ A+A+ B+B+ BIS101001, Spring 2013—Genes and Gene Expression, R.L. Rodriguez ©2013
BIS101001, Spring 2013—Genes and Gene Expression, R.L. Rodriguez 23 Molecular Basis of Dominance When the amount of enzyme produced by the
heterozygote (A+A-) is sufficient enough to generate
adequate levels of enzyme product for normal
function or the normal phenotype (i.e., haplohaplosufficient), A+ is considered dominant over A- and A),
is considered recessive to A+.
When the amount of product made by the B-B+
heterozygote is not sufficient to achieve the threshold
level (i.e., haploinsufficient), the defect B- is
dominant to B+ and B+ is considered recessive to B-.
In the case of A-A+, the wild type allele (A+) iis
dominant over the defect...
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- Spring '08