F_2 maize kernel count is as follows: 450 purple and smooth, 49 yellow and wrink
ID: 321570 • Letter: F
Question
F_2 maize kernel count is as follows: 450 purple and smooth, 49 yellow and wrinkled, 155 purple and wrinkled, 145 yellow and smooth. (A) How many genes are involved? _______ How many alleles per gene are involved? _______ (B) Is this a result of a monohybrid or a dihybrid cross? _______ (C) Fill in the genotypes of the P_1: _______ x _______ F_1: _______ Explain your allele labeling. (D) The expected F_2 phenotypic ratio of kernels is (write down the numbers along with corresponding phenotypes): (E) State the complete null hypothesis for this experiment: (F) What is the purpose of Chi-square test? (G) What is the formula for the Chi square test? _______ (H) Calculate the Chi square, show your calculations in a table (as done in class) _______ (I) Calculate the degrees of freedom (J) State the p value based on your calculations. Explain how you determined the p value. (K) What can you conclude regarding the null hypothesis? (L) State the critical p value and its significance _______Explanation / Answer
F2 maize kernel count is as follows
450purple and smooth
49 yellow and wrinkled
155 purple and wrinkled
145 yellow and sm0oth
=======================
Parental Phenotype
Purple, Smooth Kernels x Yellow, Wrinkled Kernels
Genotype AABB x Genotype aabb
F1 Phenotype--------------- Purple, Smooth Kernels
Genotype AaBb
Genotype AaBb x Genotype AaBb
AB
Ab
aB
ab
AB
AB AB
Ab AB
aB AB
ab AB
Ab
AB Ab
Ab Ab
aB Ab
ab Ab
aB
AB aB
Ab aB
aB aB
ab aB
ab
AB ab
Ab ab
aB ab
ab ab
F2 Phenotypes*
F2 Phenotypes
genotypes
Observed
Yellow, Wrinkled Kernels
aabb
49
Yellow, Smooth Kernels
aaBb, aaBB
145
Purple, Smooth Kernels
AaBb, AABB, AaBB, AABb
450
Purple, Wrinkled Kernels
Aabb, AAbb
155
A)
LOCUS1
PURPLE - kernel --------DOMINANT ALLELE
YELLOW - kernel --------RECESSIVE ALLELE
===============
LOCUS 2
SMOOTH --------DOMINANT
WRINKLED --------RECESSIVE
B) TWO ALLELES
C) DIGYBRID CROSS
F2 generation,-EXPECTED RATIO ; 9:3:3:1
The pattern above corroborates with a Mendelian mode of inheritance:
The breeding of two true breeding strains results in a single F1 progeny indicating that the purple kernel and the smooth kernel traits each correspond to dominant phenotypes,
whereas the yellow kernel and the wrinkled kernel traits correspond to recessive traits.
In the F2 generation, we find that the kernel color gene and the kernel texture gene are unlinked, or likely to be on different chromosomes.
These F2 progeny are the result of segregation of alleles and independent assortment during meiosis
==================================================================
F2 Phenotypes
genotypes
Observed
EXPECTED
(O-E)^2/E
Yellow, Wrinkled Kernels
aabb
49
50
(49-50)^2/50
0.02
Yellow, Smooth Kernels
aaBb, aaBB
145
150
(145-150)^2/150
0.16
Purple, Smooth Kernels
AaBb, AABB, AaBB, AABb
450
499
(450-499)^2/499
4.81
Purple, Wrinkled Kernels
Aabb, AAbb
155
150
(155-150)^2/150
0.16
799
799
5.15
NULL HYPOTHESIS:
F2 progeny are the result of segregation of alleles and independent assortment.
ALTERNATIVE HYPOTHESIS
F2 progeny are the NOT result of segregation of alleles and independent assortment.
======================
Chi-Square Test (df=3)
CALCULATED Chi-square =5.15
CALCULATED Chi-square 5.15 IS MORE THAN TABLE VALUE AT 5% LEVEL OF SIGNIFICANCE
ACEPT NULL HYPOTHEIS
F2 progeny are the result of segregation of alleles and independent assortment.
AB
Ab
aB
ab
AB
AB AB
Ab AB
aB AB
ab AB
Ab
AB Ab
Ab Ab
aB Ab
ab Ab
aB
AB aB
Ab aB
aB aB
ab aB
ab
AB ab
Ab ab
aB ab
ab ab
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