2) If total colour blindness was due to a gene located on the Y chromosome, then:
A) the trait would appear only when the individual inherited the dominant gene
B) males would inherit the gene from their mothers
C) it would never appear in females
D) it would be found only in the homozygous recessive condition in females
7) What is the phenotype of the female and what is the phenotype of the male with respect to the three traits shown in the above diagram? (Thumbnail #1)
Question 7 Hint:
Two possible ways to help visualize the traits is to write out the genotypes as:
•the female is
deP; the male
Dep deP dEP •the female as
ddeePP; the male as
DdEePp_____________________________
_____________________________
_______________
8) A genetic counsellor told the couple that all their sons and daughters would be expected to produce peptidase C. Do you agree with the genetic counselor? Explain. (Thumbnail #2)
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9) The first child of this couple was Rh-negative. What is the chance that the second child of this couple be a girl and be Rh-negative? Show your work. (Thumbnail #3)
_____________________________
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10) Nomenclature for writing alleles on a homologous chromosome pair
The phrase DEP/dep means the first three letters, DEP, represent the alleles that will appear, in this order, on the first homologous chromosome. The “/” signifies the following alleles, dep, will appear on the second homologous chromosome (also in the stated order). It is to be assumed that the genes will appear at the same location on both the two homologous chromosomes.
A student wrote the male genotype as DEP/dep. Do you agree? Explain. (Thumbnail #4)
_____________________________
_____________________________
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11) The sperm chromosome maps are more likely to be DeP than DEP. Explain. (Thumbnail #5)
_____________________________
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