Download File - Mrs. Sterling

Ch. 10.3 Notes
Other Patterns of Inheritance
Let’s go back…
WE have done a lot of work with simple
dominant vs. recessive inheritance. We
should give this a name:
Mendelian Inheritance
Big Picture
Many traits in our body are not a simple
dominant vs. recessive trait. There are other
factors that come into play. Can you think
of any trait in the body like this?
Eye color, hair color, height, skin color,
weight
Mendelian Dominance
Incomplete -Sometimes there is more than one dominant
Dominance allele!
-What would be the phenotype of a
heterozygous individual who has two dominant
alleles and neither can express itself fully?
You get a blend of the two
-Let’s show some examples:
If we cross a homozygous black rooster (CBCB)
with a homozygous white hen (CWCW), what
would their chicks look like?
P1 Generation:
__________
CBCB x __________
CWCW
What would the F1
generation’s chick’s
look like?
CBCW x ___________
_________
CBCW
Incomplete Dominance
Codominance -Sometimes there is more than one
dominant allele!
-What would be the phenotype of a
heterozygous individual who has two
dominant alleles and neither can express itself
fully? Spotted or striped
-Let’s show some examples:
If we cross a homozygous black rooster (BB)
with a homozygous white hen (WW), what
would their chicks look like?
P1 Generation:
__________
x __________
BB
WW
Examples in
humans:
Blood types: What would the F1
generation’s chick’s
O=recessive
look like?
A=dominant BW
_________ x ___________
BW
B=dominant
AB=codominant
Codominance
Codominance
Multiple Alleles What do you think this means?
There are more than two traits to
choose from, but no blending or
spotting
What are some examples?
Hair color & eye color in humans
Fur color in some dogs
Multiple Alleles
Polygenic Inheritance
Definition:
Many genes affect one
phenotype
So what does this mean:
Many different
phenotypes possible
What are some examples of traits
that are polygenic in humans?
Skin color & height
For skin color, the more dominant
alleles you have, the ________________
darker
your skin color.
Environmental
Factors
An individual’s phenotype depends on
____________________
as well as
genes
environment
__________________________________________.
Examples:
-Your diet influences your height
-Drugs & alcohol stunt your
growth (make you shorter and
not as well developed)
-Siamese cats turn black where
the body temperature is lower.