PLEASE ANSWER ALL QUESTIONS...IF YOU CANNOT DO NOT ANSWER 6. Colorblindness is a
ID: 322299 • Letter: P
Question
PLEASE ANSWER ALL QUESTIONS...IF YOU CANNOT DO NOT ANSWER
6. Colorblindness is a phenotype caused by an X-linked, recessive allele (Xb). Jonathan is colorblind, but his mother is not. Which of the following is a possible genotype of his mother? (Here, XB refers to the dominant, X-linked allele that does not cause colorblindness.)
Xb Xb
XB Xb
XB XB
Xb Y
7. If Jonathan's mother has another son with Jonathan's father, who is not colorblind, what is the probability that her new son will also be colorblind? (Hint: Complete a Punnett square for Jonathan's mother and father.)
0%
25%
50%
100%
8. In Nina Jablonski's article, she explains that dark skin pigmentation in humans was historically a beneficial phenotype in __________ environments. (More than one answer may be correct!)
high UVA
low UVA
low latitude (tropical)
high latitude (polar)
A.Xb Xb
B.XB Xb
C.XB XB
D.Xb Y
Explanation / Answer
Answer:
6). B. XB Xb
The X chromosomes of son will get from the mother. If the mother is heterozygous for the colorblindness, the trait can not be expressed in the mother as it is X-linked recessive disorder. But, 50% of her sons will get the disease.
7). C. 50%
XB Xb (mother, normal) x XB Y(father, normal)
XB
Y
XB
XB XB (normal female)
XB Y (normal male)
Xb
XB Xb (normal female)
Xb Y (colorblind male)
50% sons are colorblind and the remaining 50% sons are normal.
XB
Y
XB
XB XB (normal female)
XB Y (normal male)
Xb
XB Xb (normal female)
Xb Y (colorblind male)
Related Questions
Navigate
Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.