Genetics punnet squares

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Assignment_04_Heredity.rtf

Assignment 4 - Heredity

Name :

Directions: Complete the Punnett Squares below and answer all associated questions (write legibly). Be sure to include the proper terminology to describe the alleles and the ratios of the genotypes and phenotypes of the characteristics indicated for each item.

Dominate-Recessive Inheritance

In humans, the gene for dimpled cheeks (D) is dominant over its allele for smooth cheeks (d). Complete the Punnett square given the parental cross (DD x dd). Complete the associated Punnett square information.

Genotypic ratio: ___________________________________

Phenotypic ratio: __________________________________

How many off-springs are heterozygous? ________

How many off-springs are homozygous dominate? ________

How many off-springs are homozygous recessive? ________

Could they have a child who has dimpled cheeks? ________

Which number(s)? ________

Dominate-Recessive Inheritance

A homozygous mother with small ears (e) marries a heterozygous man with large ears (E). Complete the Punnett square showing the off-spring possibilities. Complete the associated Punnett square information.

How many off-springs are heterozygous? ________

How many off-springs are homozygous dominate? ________

How many off-springs are homozygous recessive? ________

Will they have a child with small ears? ________

Which number(s)? ________

Multiple-Allele Inheritance

Three babies were born in a hospital on the same night, and their blood groups were later found to be O, B, and AB. Complete the Punnett square to cross parents AB x O (simply using the ABO system) to determine the blood type possibilities their off-springs would have. Use the Punnett square information to determine which baby (A, B, AB, or O) belong to them.

How many off-springs are blood type A? ________

How many off-springs are blood type B? ________

How many off-springs are blood type AB? ________

How many off-springs are blood type O? ________

Baby _________ belongs to the AB and O parents.

Sex-Linked Inheretance

Cross the parents (XBY x XBXb). The father is normal and the mother carries the color blind trait. The allele for color blind is b and normal is B. Complete the Punnett square showing the possible off-springs from this couple. Complete the associated Punnett square information.

Could they have a child who is color blind? ________

Which number(s)? ________