Download Human Blood Groups

Incomplete Dominance
Codominance
Human Blood Types

Heterozygous phenotype is an intermediate
phenotype between the two homozygous
phenotype
Snapdragons
RR – red
WW – white
RW – pink
Human Hair
SS - straight
CC - curly
SC - wavy

Organism X exhibits incomplete dominance for
its fur color. One homozygous form is red and
the other homozygous form is blue. The
heterozygous form is purple.

Cross a blue female and a purple male.

Predict the ratios of fur color in their offspring.

Both alleles are expressed in the heterozygous
condition
Cows
RR – red (chestnut)
WW – white
RW – roan
Chickens
BB – black
WW - white
BW – black and
white
Phenotypes:
1) Roan 50%, White 50%
2) Red 25%, Roan 50%, White 25%
3) Roan 100%
4) Red 50%, Roan 50%
5) Black and White 100%
6) Black 50%, Black and White 50%
7) Black 25%, Black and White 50%, White 25%
8) Black and White 50%, White 50%



Blood groups were discovered in 1901 by Karl
Landsteiner
Adult human has 4-6 liters of blood
Parts of blood:
a. Red blood cell: contains hemoglobin which
transports oxygen to body
b. White blood cells: fight infections
c. Platelets: help blood clot
d. Plasma: made of salts and proteins
Multiple alleles (2 or more) code for traits
Ex: Blood groups
Human Blood Group Genotypes
A: IAIA
(homozygous dominant)
or
IAi
(heterozygous)
B: IBIB
(homozygous dominant)
AB: IAIB
O: ii
(co-dominant)
(homozygous recessive)
or
IBi (heterozygous)
Human Blood Donating
Blood Group
Proteins
Can Give to
Can Receive
From
A
A
A, AB
A, O
B
B
B, AB
B, O
AB
AB
AB
A, B, AB, O
O
None
A, B, AB, O
O

Named for rheses
monkey

Rh+: has the Rh
protein

Rh-: does not have
Rh protein

RR or Rr = Rh+
rr = Rh-
1) Sally is heterozygous for Blood type A and Sam has
blood type O. Predict the possible blood types of
their children.
2) Tracy has blood type AB, while her husband has
blood type A. Is it possible for them to create a
child with blood type O? Set up a cross.
3) Allison has a child with blood type AB. She has
blood type A and her husband (Phil) has blood type
AB. Is Phil the father?
1) 50% A, 25% AB, 25% B
2) Woman 1
3) Not their child
4) He could be the father
5) Garfield could be the father
6) Blood type A or B
7) Blood type A, B, AB
8) Blood type A, B, AB, O
9) Blood type O
10) Yes
11) No, all kids will be blood type O



Genetic disorders can be carried on
the X chromosome
The Y chromosome is too small, only
carries for male characteristics
Examples of sex-linked recessive
disorders: hemophilia,
colorblindness, baldness
Can cause
massive
internal
bleeding =
bruising
Hemophilia
Females
XHXH – normal for bloodclotting
XHXh – carrier for hemphilia
XhXh – hemophilia
Males
XHY – normal for bloodclotting
XhY – hemophilia
Colorblindness and Baldness
Females
XBXB – normal vision
XBXb – carrier for colorblindness
XbXb – colorblind
Males
XBY – normal vision
XbY – colorblindness
1)
John’s mom is colorblind and his dad has normal
vision. Give the genotype and phenotype ratios
for John and his siblings.
2)
Susan is a carrier for hemophilia. She marries
Bob who has hemophilia. Give the genotype and
phenotype ratios for their children.
3)
Rick wants to know if he will be bald as an adult.
Rick’s mom is not bald. Rick’s dad is bald. Rick’s
maternal grandfather is bald. Rick’s paternal
grandfather is not bald. What about Rick?