Lab 9 Elizabeth Stassenko 112514Plant GeneticsPurpose
Lab 9
Elizabeth Stassenko
11/25/14
Plant Genetics
Purpose: To predict and to identify the genotype of offspring using a Punett Square
Exercise 1: Observing a Monohybrid Cross
Hypothesis using Punett square:
Gametes
X
x
X
XX
Xx
x
Xx
xx
Data:
Questions:
A. What are the predicted ratios of the phenotypes in the plants?
I predicted ¾ will germinate as green and ¼ will germinate as yellow
B. What was the total number of seeds that germinated?
80
C. What are the actual ratios of the phenotypes displayed in the tobacco plants? D. Explain why it may be important to collect data from a larger population.
51/80 for the green germinated seeds, and 21/80 for the yellow germinated seeds. It is very important to have a large test group so the results are more proven, since the population is larger.
E. If all yellow seedlings were removed from the population, would the next generation still have a chance at displaying the yellow allele? Explain.
Yes, because one of the green seedlings may have a hidden recessive gene.
F. Would a cross between a homozygous and a heterozygous parent show the same ratios?
Explain.
It depends if the homozygous parent is homozygous recessive or homozygous dominant. If they are recessive then yes, the ratio will change.
Exercise 2: Dihybrid Cross
Procedure:
Data:
Data Table 4: Corn kernel data.
Number of Kernels
Kernel Percentage
(Divide count by total, then multiply by 100)
Kernel Coloration
Purple
180
65.2%
Yellow
96
32.8%
Total
276
Kernel Texture
Smooth
198
71.7%
Wrinkled
78
28.3%
Total
276
Data Table 6: Data from corn kernels.
Number Counted
Ratio: Number counted / total
Purple and smooth
123
123/276
Purple and wrinkled
59
59/276
Yellow and smooth
75
75/276
Yellow and wrinkled
19
19/276
TOTAL
276
Fathers Gametes
Mothers
Gametes As
As
aS as aS
AaSs
AaSs aaSS aaSs
As
AAss
AAss
AaSs
Aass
aS
AaSs
AaSs aaSS aaSs
as
Aass
Aass aaSS aass
Elizabeth Stassenko
11/25/14
Plant Genetics
Purpose: To predict and to identify the genotype of offspring using a Punett Square
Exercise 1: Observing a Monohybrid Cross
Hypothesis using Punett square:
Gametes
X
x
X
XX
Xx
x
Xx
xx
Data:
Questions:
A. What are the predicted ratios of the phenotypes in the plants?
I predicted ¾ will germinate as green and ¼ will germinate as yellow
B. What was the total number of seeds that germinated?
80
C. What are the actual ratios of the phenotypes displayed in the tobacco plants? D. Explain why it may be important to collect data from a larger population.
51/80 for the green germinated seeds, and 21/80 for the yellow germinated seeds. It is very important to have a large test group so the results are more proven, since the population is larger.
E. If all yellow seedlings were removed from the population, would the next generation still have a chance at displaying the yellow allele? Explain.
Yes, because one of the green seedlings may have a hidden recessive gene.
F. Would a cross between a homozygous and a heterozygous parent show the same ratios?
Explain.
It depends if the homozygous parent is homozygous recessive or homozygous dominant. If they are recessive then yes, the ratio will change.
Exercise 2: Dihybrid Cross
Procedure:
Data:
Data Table 4: Corn kernel data.
Number of Kernels
Kernel Percentage
(Divide count by total, then multiply by 100)
Kernel Coloration
Purple
180
65.2%
Yellow
96
32.8%
Total
276
Kernel Texture
Smooth
198
71.7%
Wrinkled
78
28.3%
Total
276
Data Table 6: Data from corn kernels.
Number Counted
Ratio: Number counted / total
Purple and smooth
123
123/276
Purple and wrinkled
59
59/276
Yellow and smooth
75
75/276
Yellow and wrinkled
19
19/276
TOTAL
276
Fathers Gametes
Mothers
Gametes As
As
aS as aS
AaSs
AaSs aaSS aaSs
As
AAss
AAss
AaSs
Aass
aS
AaSs
AaSs aaSS aaSs
as
Aass
Aass aaSS aass