I am having problems with this homework. The instructions are not 4739

Experiment 1: Punnett square crosses

Materials
Red beads
Blue beads
Green beads
Yellow beads
2 100mL Beakers

Procedure
1. Set up and complete Punnett squares for each of the following crosses:
(remember Y = yellow, and y = blue)
Y Y and Y y

Y Y and y y

     

Y

Y

Y

YY

YY

y

Yy

Yy

     

Y

Y

y

Yy

Yy

y

Yy

Yy

a) What are the resulting phenotypes?

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All Rights Reserved

The punnet square shows all of the possible combinations that would result
from the mating of the given genotypes. In this example the dominant allele is
represented by Y, and determines the color of the corn to be yellow. The
results from the square is: 100 percent of the offspring will have a yellow
phenotype, because every combination expresses the dominant allele Y.

b) Are there any blue kernels? How can you tell?
For a recessive allele to be expressed there must be two recessive alleles
present.In this particular example, there is no combination that leads to a
homozygous recessive genotype or yy. Meaning there is no blue corn
expressed.

2. Set up and complete a Punnett squares for a cross of two of the F1 from 1b
above:
a) What are the genotypes of the F2 generation?
The results of the completed punnet square shows the probability of producing
a homozygous recessive offspring is 25%, a 50% chance of producing a
heterozygous offspring and a 25% chance the offspring will be homozygous
dominant.

b) What are their phenotypes?
The results show a 75% chance the offspring will be yellow and 25% chance
the offspring will be blue.

© 2010 eScience Labs, Inc.
All Rights Reserved