The document discusses multiple alleles and uses blood type as an example. It notes that there are three main alleles (Ia, Ib, Io) that determine blood type. The possible genotypes are Ia Ia, Ia Ib, Ia Io, Ib Ib, Ib Io, and Io Io. The possible phenotypes are A, B, AB, and O.

1. Multiple alleles Starter activity Distinguish the phenotype features of the following alleles (Hb haemoglobin) Hb a / Hb a Hb a / Hb s Hb s / Hb s

2. Learning objectives Understand the term multiple alleles List the genotype and phenotype of the blood groups To draw genetic cross tables between blood groups

3. http://courses.bio.psu.edu/fall2005/biol110/tutorials/tutorial5.htm http://library.thinkquest.org/20465/genes.html When there are 3 or more alleles for a specific locus, this means that there are multiple alleles. In humans, the ABO blood group system involves 3 different alleles What is the gene locus referred for the blood group ( ) which represents for isoheamagglutinogen What does gene represent? The 3 alleles for this are (Ia, Ib), (Io, Ia), Ib

4. Io is recessive to Ia and Ib the result is that no antigen is produced on the cell surface. How many alleles does a person carry? How many possible genotypes are there? How many possible phenotypes are there? List the possible allele combinations for blood group A and B What is the allele combination for blood group AB What is the allele combination for blood group O It is this system that is used to determine if certain family members can be compatible for blood transfusion

5. Genetic cross Parents : Group A / B Phenotype : Ia Io / Ib Io Genotype : Ia Io / Ib Io Gametes: Ia Io Ib Io IaIb IbIo IaIo IoIo

6. Genetic cross Parents : Phenotype Genotype Gametes