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Incomplete & Codominance. Biology Honors. Exceptions to Mendel’s Work. Pea plants show complete dominance only Ex: purple flowers are dominant to white flowers PP=purple Pp =purple p p =white Sometimes genetics are more complex than that! (actually, they usually are).
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Incomplete & Codominance Biology Honors
Exceptions to Mendel’s Work • Pea plants show complete dominance only • Ex: purple flowers are dominant to white flowers • PP=purple • Pp=purple • pp=white • Sometimes genetics are more complex than that! (actually, they usually are)
RR = red rr = white Rr = pink Incomplete Dominance • Blending of traits • Neither allele dominates the other • Three genotypes = three phenotypes • Example: • REDflower x WHITE flower PINKflower
Incomplete Dominance Make a key to help you! RR = Red Rr = Pink rr = White
Practice, practice, practice! • Oompa Loompa can have red (R), blue (r) or purple hair. Purple hair results from the heterozygous condition. Make a "key" showing the genotypes and phenotypes for hair color. • RR = red • rr = blue • Rr = purple
Olivia Oompa is married to Odo Oompa and they both have purple hair. What color hair and in what proportion would you expect their children to have?
Codominance • Both traits are shown • Both alleles are dominant together • red x whitered & white spotted RR x rrRr • Think “co-” is together (cooperate, coexist)
Codominance • Make a key to help you! RR = Red Rr = Roan (red & white) rr = White
Practice, practice, practice • In a certain species of frogs, purple legs (L) are dominant to black legs (l), but heterozygous genotype results in purple and black legs. Set up a key to show this.
A purple and black legged male mates with a black legged female. What is the chance of having purple legged offspring? Show the cross.