Multiple Alleles:

1

• Multiple Alleles
• BLOOD TYPES
• An application of Co-dominance Mode of Inheritance

2
CO-DOMINANCE

• Review
• Co-dominance
• Two dominant alleles are expressed at the same
  time.

3
CODOMINANCEMULTIPLE ALLELES

• Some traits have more than two alleles.
• For blood types, 2 of the genes are codominant
  and one is recessive.
• 3 possible genes
• A and B are codominant
• O is recessive.
• Genes A IA B IB O i

4
The Story of Blood Transfusions

• 1492
• As Pope Innocent VIII sank into a coma, the
  blood from 3 boys was given through the mouth.
  All 4 individuals died.
• Mid-1600s
• A British physician transfused sheeps blood into
  a soldier. The soldier died a painful death.
• 1881
• First recorded human-to-human blood transfusion
  by British physician James Blundell. Patient
  shows initial improvement and then dies.

5

• 1901
• Austrian physician Karl Landsteiner discovers the
  three main human blood groups (A, B and Che
  later changed C to O). For this, he was awarded
  the Nobel Prize.

• He mixed red blood cells with different kinds of
  blood. When he mixed A blood with red blood
  cells from the B group, he saw clumping. The
  same thing happened when he did the opposite.
• He found that when he put red blood cells from
  group C into any other blood type, there was
  never any clumping.

6

• 1902
• Dr. Alfred von Decastello and Adriano Sturli
  identify AB blood type which clumps in both A
  and B blood.
• This clumping is called agglutination.

• 1917
• Dr. Oswald Robertson collects and stores type O
  blood to be used for casualties in World War I.
• This would be the first blood bank.

• 1907
• Dr. Reuben Ottenberg, New York, performs the
  first transfusion using cross matching (matching
  blood types).
• Over the next several years, he virtually
  eliminates transfusion reactions.

7
Picture of Red Blood Cells
8
ANTIGEN (Agglutinogen-kind of protein)

• On the surface of the cell membrane of a red
  blood cells, there are proteins protruding out.
• These proteins are called antigens or
  agglutinogens.
• They are used to identify the cells as self.

9

• Antibodies
• Your bodys defense mechanism. Antibodies attack
  foreign substances.
• If the wrong blood type is transfused into a
  person (such as A into an O person), the
  antibodies in the recipients blood will try to
  destroy the group A cells.

10
Why, when you mix certain peoples blood, does it
cause clumping

• Example Anti-A antibodies attach to A antigens,
  binding red blood cells together and causing
  clumping.
• The kidney tries to filter the clumps out of the
  blood and the kidneys can become damaged to the
  point of kidney failure.

11
(No Transcript)
12
(No Transcript)
13
(No Transcript)
14
(No Transcript)
15
(No Transcript)
16
(No Transcript)
17
(No Transcript)
18
(No Transcript)
19
(No Transcript)
20
(No Transcript)
21
(No Transcript)
22
(No Transcript)
23
(No Transcript)
24
(No Transcript)
25
Example Cross a type A father and a type O
mother. One of their children is a type O. Is
this child adopted?
26
Example Cross a type A father and a type O
mother. One of their children is a type O. Is
this child adopted? (2 possible punnett
squares)
27
Example Cross a type A father and a type O
mother. One of their children is a type O. Is
this child adopted? (2 possible punnett squares)
28
ExampleCross a type A father and a type O
mother. One of their children is a type O. Is
this child adopted? (2 possible punnett squares)
29
Example Cross a type A father and a type O
mother. One of their children is a type O. Is
this child adopted? (2 possible punnett squares)
30
Example Cross a type A father and a type O
mother. One of their children is a type O. Is
this child adopted? (2 possible punnett squares)
31
UNIVERSAL DONOR VS UNIVERSAL RECIPIENT

• What type of blood would be the Universal Donor
  and why?
• Type O because it has no antigens on its
  surface to be recognized by antibodies.
• What type of blood would the Universal Recipient
  and why?
• Type AB because it has no antibodies to
  recognize and attack foreign blood types.

32
Rh Factor

• Rh positive indicates the presence of the Rh
  antigen on the red blood cell.
• This is dominant.
• or -
• Rh negative indicates the lack of Rh antigen on
  the surface of the red blood cell.
• This is recessive.
• - -

33
Anti-Rh Antibodies

• A person only develops anti-Rh after exposure to
• Rh-positive cells through transfusion or
  pregnancy.
• Leakage of red blood cells from an Rh baby into
  a Rh- mothers system during delivery will cause
  a build up of the anti-Rh antibodies in the
  mothers blood.
• This takes awhile so probably wont affect the
  first baby.
• The anti-Rh antibodies can pass through the
  placenta and enter the circulatory system of the
  next Rh baby.
• This will clump the babys red blood cells.

34
ExampleCross a type Rh father and a Rh-
mother. What is the chance that their baby will
cause a build up of anti-Rh antibodies in the
mother?
35
ExampleCross a type Rh father and a Rh-
mother. What is the chance that their baby will
cause a build up of anti-Rh antibodies in the
mother? (2 possible punnett squares)
36
ExampleCross a type Rh father and a Rh-
mother. What is the chance that their baby will
cause a build up of anti-Rh antibodies in the
mother? (2 possible punnett squares)
37
ExampleCross a type Rh father and a Rh-
mother. What is the chance that their baby will
cause a build up of anti-Rh antibodies in the
mother? Baby would have to be . (2 possible
punnett squares)
100 chance
38
ExampleCross a type Rh father and a Rh-
mother. What is the chance that their baby will
cause a build up of anti-Rh antibodies in the
mother? (2 possible punnett squares)
100 chance
39
ExampleCross a type Rh father and a Rh-
mother. What is the chance that their baby will
cause a build up of anti-Rh antibodies in the
mother? (2 possible punnett squares)
100 chance
50 chance
40
ExampleYou can then put Rh factors together
with Blood Types to get a complete blood type.If
the mother was homozygous A- and the father was
heterozygous A here are the two possibilities
you could get
41

• Most common blood types
• A and O-
• make up about 72 of the population.
• Least common blood type
• AB-
• make up only about 1 of the population

42
Extra Credit?!?

• If your parents know their blood types, draw a
  punnett square showing what blood types you could
  possibly be!
• Let me know if you need help!

43
(No Transcript)