Question

AL11 Activity 4: Multiple alleles with Codominance 1. Some traits in a population are determined by multiple alleles. For example, there are three alleles for Mood type in the human population (type A), P type B). and i lypeo). Different combinations of these alleles (each individual can inherit only two alleles) produce the four different blood types (phenotypes) that we are familiar with Based upon the symbols alone, what can you predict about the relationships between each of the following allele pairs (complete dominance, codominance, or incomplete dominance)? & 1 and 10 b. Mando c. A and TT 2. Determine the genotypes that code for each of the four human blood types. Careful - individuals with two of the blood types can have more than one genotype) . Blood type (phenotype) Genotype(s) 3. Construct Punnett squares to help you determine the expected genotypic and phenotypic ratios of children resulting from the following crosses. a. Type AB x Type B (heterozygous) Genotypic ratio: Phenotypic ratio: 101

Answer 1

1. I^Aand I^O = Complete dominance

I^B and I^O= Complete dominance

I^Aand I^B= Co-dominance

2.

Blood type (Phenotype)	Genotype
O	IOIO
A	IAIA or IAIO
B	IBIB or IBIO
AB	IAIB

3. a. Type AB (I^AI^B) x Type B heterozygous (I^BI^O)

	IB	IO
IA	IAIB	IAIO
IB	IBIB	IBIO

Genotypic ratio: I^AI^B:I^AI^O:I^BI^B:I^BI^O=1:1:1:1

Phenotypic ratio: Blood group AB : Blood Group B : Blood group A= 1:2:1

b. Type A heterozygous (I^AI^O) x Type B heterozygous (I^BI^O)

	IB	IO
IA	IAIB	IAIO
IO	IBIO	IOIO

Genotypic ratio: I^B I^O:I^OI^O:I^AI^B:I^AI^O= 1:1:1:1

Phenotypic ratios: Blood group B:Blood group O:blood group AB:Blood group A= 1:1:1:1

c) Type O (I^OI^O) x Type AB (I^AI^B)

	IA	IB
IO	IAIO	IBIO
IO	IAIO	IBIO

Genotypic ratio: I^AI^O:I^BI^O= 1:1

Phenotypic ratio: Heterozygous A: Heterozygous B= 1:1

d) Type AB (I^AI^B) x Type A heterozygous (I^AI^O)

	IA	IO
IA	IAIA	IAIO
IB	IAIB	IBIO

Genotypic ratio: I^AI^B:I^AI^O:I^AI^A:I^BI^O=1:1:1:1

Phenotypic ratio: Blood group AB : Blood Group A: Blood group B =1:2:1

4.a. True (I^AI^OxI^AI^O)

b. False (I^AI^B cannot produce O blood child).

c. True (I^AI^BxI^AI^B= 25% chance of A blood group)

d. False ( for AB blood group both parents should have A or B allele).