punnettsquares Mr. Smith
Lindsay Middle School 7th Grade Life Science
Punnett Square (Scenarios)

Using a blank sheet of paper, set up a Punnett square for each scenario and compile all necessary information.

Scenario #1 (Use uppercase R to identify the dominant characteristic & lowercase r to identify the recessive characteristic.)

In peas, the color yellow is dominant to the color green.  A homozygous yellow pea is crossed with a homozygous green pea plant.  What will the genotypes and the phenotypes of all of the possible offspring be?  Indicate the probability of each outcome.

Scenario #2 (Use uppercase H to identify the dominant characteristic & lowercase h to identify the recessive characteristic.)

In peas, the smooth shape is dominant to the wrinkled shape.  A heterozygous smooth shaped pea is crossed with a homozygous wrinkled shaped pea.  What will the genotypes and the phenotypes of all of the possible offspring be?  Indicate the probability of each outcome.

Scenario #3 (Use uppercase D to identify the dominant characteristic & lowercase d to identify the recessive characteristic.)

In humans, the widow's peak (hairline) is dominant and the straight hairline is recessive.  Parent 1 is heterozygous widow's peak (hairline) and Parent 2 is homozygous straight (hairline).  What will the genotypes and the phenotypes of all of the possible offspring be?  Indicate the probability of each outcome.

Scenario #4 (Use uppercase P to identify the dominant characteristic & lowercase p to identify the recessive characteristic.)

In humans, the gene for green eyes (color) is recessive and
the gene for brown eyes (color) is dominant.  Parent 1 is purebred for green eyes and parent two is hybrid for brown eyes.  What will the genotypes and the phenotypes of all of the possible offspring be.  Indicate the probability of each outcome.

Scenario #5 (Use P to identify the dominant characteristic & lowercase p to identify the recessive characteristic.)

A scientist is conducting an experiment with 2 plants.  One plant is homozygous tall and the other is heterozygous tall.  The tall gene is dominant to the short.  What will the genotypes and the phenotypes & phenotypes of all the possible offspring?  Indicate the probability of all offspring.

Scenario #6 (Use M to identify the dominant characteristic & lowercase m to identify the recessive characteristic.)

Step 1

In a certain bean, the color brown is dominant to the color black.  A homozygous brown bean is crossed with a homozygous black bean.  What are the possible genotypes & phenotypes of all of the possible offspring?  Indicated the probability of all offspring.

Step 2

In their second generation, a heterozygous brown bean is crossed with a heterozygous brown bean.  What are the possible genotypes & phenotypes of all of the possible offspring?  Indicate the probability of all offspring?

Scenario #7

Gregor Mendel was interested in beans plants.  He crossed a  hybrid full shaped bean pod with a purebred flat bean pod.  (A full shaped bean pod is dominant to a flat bean pod.) 

Use a capital letter F for the dominant allele and lowercase f for the recessive allele. 

What are the genotype and the phenotype of the offspring?  What is the probability that he'll get a flat bean pod?

Scenario #8

Use an upper case D for the dominant trait. (dimples)
Use a lower case d for the recessive trait. (no dimples)

Two parents decide to have kids.  Both parents have dimples, however one is heterozgous for dimples and the other is homozygous for dimples.  The gene for dimples is dominant.

What is the genotype for all of the offspring.  What is the phenotype?  What is the probability that the offspring will have dimples?

Scenario #9

Make a Punnett Square showing the possible offspring of two parents (one - AB & one - OO).  What will the genotype of the offspring be?  What will the phenotype of the offspring be?

Scenario # 10

What's the Blood Type?
Make a Punnett Square showing the possible offspring of two
parents.  One Parent has Blood Type AB and the other has Blood Type AO.  What will the genotype of the offspring be?  What will the phenotype of the offspring be?

Scenario #11

Sex-Linked Genetic disorders

In a certain family, hemophilia is quite common.  If a mom is a carrier and dad is "normal", what will happen with the offspring?

Scenario #12

Sex-Linked Genetic disorders

In a certain family, colorblindness is quite common.  If a mom is color blind, but the dad is "normal", what will happen with the offspring?

Scenario #13

Sex-Linked Genetic disorders

Muscular Distrophy

Mom is is "normal", but dad is infected with the disease.  What impact will that have on their male and female offspring?

Scenario #14

Sex-Linked Genetic disorders

retinitis pigmentosa (an eye disease that causes tunnel vision and progressive loss of sight)

Mom is a carrier and dad is normal.  What will happen to their offspring?

Scenario # 15

Queen Victoria was a carrier of the recessive allele for hemophilia. Her husband was normal.  Together, they had 9 children (4 males and 5 females).  Of the 4 males, 1 was infected and he married a normal female.  (Together they had a carrier daughter who married a normal male.)  Of the 5 females, 2 were carriers and they both married normal males. (One of those families had 3 kids/ 2 carrier females and 1 infected male.  The other family had 1 normal male, 2 infected males and 1 carrier female.)
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Last updated  2008/09/28 08:28:46 EDTHits  1719