Problem: Test the probability of a cross between the two parents given their genotypes.

The following traits are found in humans:

Trait / Dominant / Recessive / Color of Paper Chromosome
Widow’s Peak / Widow’s Peak (W) / No Widow’s Peak (w) / Orange
Albinism / Normal (N) / Albino (n) / Yellow
Freckles / Freckles (F) / No Freckles (f) / Blue
Color Blindness / Normal Vision (B) / Colorblind (b) / Pink

Blood type will be on purple colored paper. Note: Blood type alleles for A and B are co-dominant to each other (meaning that they both go together).

Phenotype (Blood Type) / Genotype
A / IA IA or IA i
B / IBIBor IB i
AB / IA IB
O / ii

A man and a woman have children. Their genotypes are listed below:

Trait / Mom’s Genotype / Dad’s Genotype
Widow’s Peak / Ww / Ww
Albinism / NN / Nn
Freckles / Ff / Ff
Color Blindness / XBXb / Xb Y
Blood type / IA IB / ii

TASK 1: Complete the Punnett Squares for each trait on the worksheet using the parent genotypes. Next to each, write the predicted genotype and phenotype probabilities of the offspring.

TASK 2: Open the baggie and use the charts above to make sure you have the correct colored chromosomes. There should be 2 alleles for each trait for the mother and the father. Then FOLD the chromosomes in half so the letters for the alleles are inside. Place all of mom’s chromosomes into BEAKER A and all of dad’s chromosomes into BEAKER B. Answer the question for task 2.

TASK 3: Shake up the beakers containing the chromosomes. For the first child, randomly choose one of each colored chromosome from mom’s beaker and one of each colored chromosome from dad’s beaker. Answer the question for task 3on the student worksheet.

TASK 4: Fill in the table on the student worksheet to show this child’s genotype, phenotype, Repeat until you have pulled one allele from each parent for each trait listed on the data table.

TASK 5: Fold the alleles back up and put them back into the correct beakers. Mix them up. Repeat Tasks 3 and 4, 3 more times. Fill in the data tables on the worksheet.

TASK 6: Complete the table to compare your predicted results from Task 2 to your experimental results from Task 4 and 5. Analyze this information by answering the question and make a conclusion on the student worksheet.

TASK 1: (3 pts each)Complete the Punnett squares using the Parent’s genotypes. Write the predicted genotype and phenotype ratios next to the Punnett square.

Widow’s Peak:Color Blindness:

Albinism:Blood Type:

Freckles:Sex:

TASK 2: (2 pts)Read the procedure and explain why one allele for each gene goes on each chromosome? ______

______

TASK 3:(2 pts) Read the procedure and explain why does the child get one chromosome from each parent? ______

______

TASK 4: (5 pts)

Trait / Genotype / Phenotype
Widow’s Peak
Albinism
Freckles
Color Blindness
Blood Type
Sex of the child

TASK 5: (5 pts each)

Trait / Genotype / Phenotype
Widow’s Peak
Albinism
Freckles
Color Blindness
Blood Type
Sex of the child
Trait / Genotype / Phenotype
Widow’s Peak
Albinism
Freckles
Color Blindness
Blood Type
Sex of the child
Trait / Genotype / Phenotype
Widow’s Peak
Albinism
Freckles
Color Blindness
Blood Type
Sex of the child

TASK 6: (8 pts)

Trait / Predicted Genotype Ratio / Experimental Genotype Ratio / Predicted Phenotype Ratio / Experimental Phenotype Ratio
Widow’s Peak
Albinism
Freckles
Color Blindness
Blood Type
Sex of the Child

Are your predicted results the same as your experimental results*? In detail, analyze and come to a conclusion which explains why or why not.

______

***Predicted genotype and phenotype ratios come from your Punnett Squares in Task 1. Experimental genotype and phenotype ratios come from the chromosomes you pulled out. Determine the number of offspring that has each genotype and phenotype for your experimental ratio.