The document discusses multiple alleles in the context of ABO blood groups. It explains that ABO blood groups are controlled by a gene that has three allelic forms - IA, IB, and i - which produce different sugars and determine the presence of antigens and antibodies. Depending on the combination of alleles, an individual can have one of four blood types - A, B, AB, or O - which determines what blood types can be accepted in a transfusion.

1. MULTIPLE ALLELES
( BLOOD GROUP)

2. WHAT ARE ALLELES ?
• Alleles are the gene which code for a pair of
contrasting traits.
• they are the slightly different forms of the
same gene.

3. MULTIPLE ALLELES
• If there are more than two allele i.e., three
alleles , governing the same character , then
it is called as multiple alleles.
• It is found only when population studies are
made.

4. ABO Blood Group
• ABO blood group are controlled by the gene
I.
• Gene has three allelic form: IA , IB , i
• Alleles IA and IB produce slightly different
form of the sugar while allele i does not
produce any sugar.

5. GENOTYPE PHENO
TYPE
TERMINAL
SUGAR OF
ANTIGEN
ANTIGEN
PRESENT
ANTIBODI
ES
PRESENT
RED CELL
TYPE
AGGLUTIN
ATION
TRANSFUS
IN
ACCEPTED
FORM
IAIA or IA i A A-
galactosamine
Antigen-A Anti-B B, AB A,O
IB IB OR IB i B B-
galactosamine
Antigen-B Anti-A A,AB B,O
IA IB AB A-
galactosamine
B-
galactosamine
Antigen-A
Antigen-B
None None A,B,AB
ii O None None Anti-A
Anti-B
A,B ,AB O

6. THANK YOU