A)
Incomplete Dominance:
* when one allele (form of a gene) is partially dominant over the other
* it is a blending of the alleles
ex. Four O'clock Flowers (key below)
R = red
W = white (can also use R')
RW or WR= pink can also be RR' or R'R)
More practice problems
4) Use a Punnett square to show the offspring of a cross between a red
Four O'clock flower and one that is heterozygous. Give the phenotypes
and genotypes of the offspring.
5) Use a Punnett square to show the offspring of a cross between a homozygous white Four O'clock flower and one that is heterozygous pink. Give the phenotypes and genotypes of the offspring.
B) Codominance:
* this time, both the alleles are expressed,
but they are not blended together
* in humans, this is like hair texture and blood groups
ex. cattle coat color (key below)
CR = red
CW = white
CWCR or CRCW = roan (where both red and white are expressed
Genetics
a wonderful review of all genetics--right now focus on the questions What is heredity? and What is a trait?
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