Download Chapter 3.7

Chapter 3.7
What are incomplete dominance
and codominance?
INCOMPLETE DOMINANCE:
It means that the
offspring will show a
blending of traits from
each parent.
Homozygous red
flowering plants are
crossed with
homozygous whiteflowering plants. It will
produce pink-flowers.
CODOMINANCE: neither allele is dominant
nor recessive. Both alleles show up in a
future organism. Codominance is different
from incomplete dominance because
incomplete dominance does not involve
blending.
CODOMINANCE in
CHICKENS: There is a
kind of chickens that
has a gene for black
feathers and a gene for
white feathers. Neither
of these gene is
dominant over the
other.
Checking concepts: What gene combination
do pink four o’clock flowers have?
What is the result of a cross between
homozygous red and homozygous
white four o’clock flowers?
What color feathers will a chicken with the
gene combination WW have?
What is the gene combination for a chicken
with black and white feathers?
What gene combination will have a 50%
chance of occurring if two heterozygous
black and white chicken are mated?
Why are capital letters used to represent all
the genes for feather color in certain types of
chicken?
Why does blending occur only in organisms
that are heterozygous for a certain trait?