Download Codominance and Incomplete Dominance

Codominance and Incomplete
Dominance
Dominance
• What is dominance?
• What makes a gene
dominant?
• What makes a gene
recessive?
• These factors affect
most genes and cause
them to be expressed
or hidden
Dominance
• Some genes do not play
by the same rules
• These genes have
special ways of being
expressed
• These genes are not
dominant or recessive
Codominance
• There are several genes
that have two different
dominant traits
• If these two dominant
traits are expressed at
the same time we call it
codominance
• Codominant genes are
genes that express both
alleles in the pairing
Codominance
• We call them
codominant genes
because both alleles in
the gene are expressed
• Both dominant traits
are represented in
organisms
Codominance
• Cows are a great example
of codominance
• There are cows that are a
red color
• There are cows that are a
white color
• Both of those cows have a
dominant phenotype
• However when we have
one dominant gene that
is white and one that is
red we have both
expressed
Codominance
Incomplete Dominance
• Sometimes genes do
not have such an easy
idea for dominance
• Sometimes with genes
there is no defined
dominant gene
• When there are two
different genes that are
considered dominant,
they can blend
Incomplete Dominance
• Genes that blend with
two dominant alleles
are called incomplete
dominance genes
• These genes can be
found in many different
types of organisms
Incomplete Dominance
• Snapdragons are a good
example of incomplete
dominance
• There are red
Snapdragons
• There are white
Snapdragons
• There are also pink
Snapdragons that are
formed with a
heterozygous genotype
Incomplete Dominance