Shown below is the arrangement of three genes in a heterozygous individual. All three genes have a classic dominant/recessive pattern of inheritance. w+ y+ c w y c+ a. What phenotypes would you expect in the parental, single crossovers and double crossovers after a cross with a homozygous recessive individual. b. If we know w is closer to y than it is to gene c, put the four categories above in order from highest frequency to lowest frequency.
a).
w+ y+ c / w y c+ (triple heterozygote) x wyc/wyc (tester)---Testcross
wyc/wyc genotype produces only one type of gametes, wyc. Triple hybrid produces 8 types of gametes. Hence, the 8 gametes produced by triple heterozygote represent their phenotypes.
Class of gametes |
Genotype of gametes |
Phenotype |
Parental |
w+y+c |
w+y+c / wyc |
wyc+ |
wyc+ / wyc |
|
Single crossover between w & y |
w+yc+ |
w+yc+ / wyc |
wy+c |
wy+c / wyc |
|
Single crossover between y & c |
w+y+c+ |
w+y+c+ / wyc |
wyc |
wyc / wyc |
|
Double crossovers |
w+yc |
w+yc / wyc |
wy+c+ |
wy+c+ / wyc |
b).
Always parental combinations are more numbered than any type of recombinants and double recombinants are very less numbered than any type of progeny.
Based on the distance between the genes, higher distance between the genes are more numbered in single crossovers than lower distantly arranged genes.
In the given question, it mentioned as gene “w” is closer to “y” than gene “c”. Therfore, the following categories are from higest frequency to lowest frequency.
Class of gametes |
Phenotype |
|
Parental |
w+y+c / wyc |
Very high |
wyc+ / wyc |
||
Single crossover between y & c |
w+y+c+ / wyc |
High |
wyc / wyc |
||
Single crossover between w & y |
w+yc+ / wyc |
low |
wy+c / wyc |
||
Double crossovers |
w+yc / wyc |
Very low |
wy+c+ / wyc |
Shown below is the arrangement of three genes in a heterozygous individual. All three genes have...
Show below is the arrangement of three genes in a heterozygous individual. All three genes have a classic dominant/recessive pattern of inheritance. w+ y+ c w y c+ What phenotypes would you expect in the parental, single crossovers and double crossovers after a cross with a homozygous recessive individual. If we know w is closer to y than it is to gene c, put the four categories above in order from highest frequency to lowest frequency.
12. What is a suspected heterozygous individual crossed with in
a test cross?
A. Homozygous dominant
B. Homozygous recessive
C. Heterozygous dominant
D. Heterozygous recessive
13. Which of the following genotypes is possible in the
offspring of a homozygous male with blood group A and a female with
blood group B?
The answers are 12B, 13B, 14C can you explain how?
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Peas heterozygous for three independently assorting genes were intercrossed. (example cross: Aa Bb Ccx Aa Bb Cc) What proportion of the offspring will be homozygous for all three recessive alleles? What proportion of the offspring will be homozygous for one gene and heterozygous for the other two?
number 8
D. ? 8. A female fruit fly is heterozygous for two genes, A and B. Gene A is X-linked, Whereas gene B is not. If this female is mated to a male that is recessive for both genes, predict the frequency of progeny genotypes. Show your work. A. Identify parental genotypes B. Identify the gametes C. Perform the cross D. Calculate the frequencies:
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You have three genes on the same chromosome - A, B and C. Each gene has two alleles in a dominant/recessive relationship. For these genes the homozygous recessive has the mutant phenotype for that trait, the dominant phenotype = wild type for that trait. allele A is dominant to a; phenotype a = mutant for trait a; phenotype A = wild type for trait A allele B is dominant to b; phenotype b = mutant for trait b; phenotype B...
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