Download Warm Up

Okay – Not
really
Other Patterns of
Heredity
 Polygenic traits = several genes influence the trait.
 Examples: Eye color, weight, height, hair color, & skin
color.
Incomplete dominance

 Incomplete dominance = a trait that is in between the
two parent traits.
 Ex: Red snapdragon flower crossed with white
snapdragon flower results in
PINK snapdragon flowers.
Co-dominance

 Co-dominance = Two dominant alleles are expressed
at the same time.
 EX: Homozygous red horse crossed with a
homozygous white horse results in
Red AND white horse
Multiple Alleles

 Genes with 3 or more alleles are said to have
multiple alleles.
 EX: Blood type in humans (ABO)
Blood types

Some traits are caused by mutations

 Sickle cell anemia
 Recessive genetic disorder.
 Red blood cells are sickle shaped.
 Don’t move well through vessels.
Possible Genotypes
RR = normal red blood cell
Rr = slightly curved red blood cell
rr = sickle-shaped red blood cell
In tropical areas of the world, being
heterozygous for sickle cell anemia is not so
bad.
It provides some immunity to the organism
Responsible for malaria.
Hemophilia

 Recessive genetic disorder.
 Blood cannot clot well.
 Sex-linked trait.
 Mostly affects males.
What gender has a greater chance of getting hemophilia?
Warm Up

 What are the 4 main blood types?
Day 4 Notes
Blood Type = Multiple Alleles &
Codominance
Blood type in
humans is controlled
by 3 alleles
 A, B, and O
 A & B are
codominant
 O is recessive
Phenotype
Genotype
A
AA or AO
B
BB or BO
AB
AB only
O
OO only
Blood type continued…
 A-type can only receive A or O blood

 B-type can only receive B or O blood
 AB-type can receive A, B, O, AB blood
 Universal Receiver
 O-type can only receive O blood
 Universal Donor
Problem 1: Is a type O possible in this
situation?

 Could you please help me? I have a question that is
NOT a homework question. I am a Junior in High
School. "Could a man with type B blood and a
woman with type AB produce a child with type O
blood?" I think not, because type O is recessive, and
the B's seem to be dominant. My cousin thinks yes.
Thank you for your help.
IMPOSSIBLE
Problem 2: What are the potential blood types of the
father of my son?

 I have been reading your info about inheritance of
blood types and I am getting very confused! I am
trying to figure out what blood type the father of my
son could have since my son and I are both type A.
Could you please help?

The father could be:
 A. A, AB, B, or O
 B. Either A or B
 C. Either A or O

 http://nobelprize.org/educational_games/medicine
/landsteiner/