Lecture 10  Multiple Alleles and Assorted Topics

I. Multiple Alleles

Most genes exist in populations in more than two allelic forms.

EX.  ABO blood groups in human population:

Four possible phenotypes for one character:
A,  B, AB, or O type.

A, B, refer to two carbohydrates on the surface of red blood cells.

A:  A substance alone on the surface of RBC.

B:   B substance alone on the surface of RBC.

AB:  A and B substance, both exist on the
         surface of RBC.

O:     Neither A nor B substance exist on the
          surface of RBC.

IA:  code for the production of A substance.

IB:  code for the production of B substance.

i:     giving rise to neither A or B sunstance.

ii:  receive homozygous.
IA  and  IB alleles are codominant, both are
expressed in the AB phenotype, and both are dominant to the i allele.

Six genotypes are possible to control ABO character.
Phenotype group Genotype Antigen Antibodies present 
in blood serum
O ii No a + b
A IA IA        IAi A b
B IB IB        IBi B a
AB IA IB A  B no

Matching compatible blood groups is critical for blood transfusions.

O type can be a universal blood donor.

AB type can receive blood from A type, B type and O
type donor.

Pseudoscience:  Blood type and Character (Donít believe it)

The personalities of each blood type.  Mr.Masahito and Toshitaka Nomi (November 23, 1997)
Type O Strongly purpose-oriented. Straight desire. Conscious of powerrelationship. Know how to take chances.  Dislike to be subordinate.Expressive.
Type A Considerate about everything. Prefer peaceful human relations.Slow to trust people. Observe social rules and customs.Regard social orderas important Restrain action and expression
Type B Dislike restrictions and one's own way. Non-stereotyped action.Non-stereotyped thinking. Self-conscious and not warped expressions. Makesless distinction of things. Not conscious of circumstances. Don't caresocial rules and customs.
Type AB Rational thinking. Good critic and analyst. To participateand contribute to the society. Good at adjusting human relations. Hopeto be in harmony with the society. Feels distant from the society.