APPROVED SOLUTION
The following problem set is worth 75 points.
Problems are due to the instructor NLT
1600 on 14 Sept 07.
A Documentation of Written Work Coversheet must be
initialed, signed, and attached.
Any assistance outside of the instructor must be
documented and properly acknowledged.
This includes websites, textbooks, personnel
and resources outside of original thought.
For assistance or further guidance, see your
instructor.
For full credit, show all work, and calculations.
Use the correct pedigree symbols as
outlined in your textbook.
Attach additional worksheets as needed.
DOMINANCE & RECESSIVENESS
1.
(10 pts) The lack of pigmentation, albinism, in humans is the result of a recessive
allele
a
and normal pigmentations is the result of its dominate allele
A
.
Two normal
parents have an albino child.
Determine the probability that:
(a) the next child is albino.
Explain and complete the Punnett square.
In order to have an albino child, both parents must be carry
the recessive allele.
Parental cross must be Aa x Aa thus there
is ¼ or 25% chance
(b) the next two children are albinos.
Each cross will yield the same probability.
Thus, the probability of one child being
albino is multiplied by two or ¼ x ¼ = 1/16
(c) What is the chance of these parents producing two children, one albino and the other
normal?
Chance one normal = ¾
Chance one albino = ¼
Using the multiplication rule:
Chance two children, one albino and one normal = 2( ¾ x ¼) = 3/8
1
P
1
A
a
A
AA
Aa
a
Aa
aa
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APPROVED SOLUTION
2.
(19 pts) Black wool of sheep is due to a recessive allele
b
and white wool to its
dominant allele
B
.
A white ram (male) is crossed to a white ewe (female), both animals
carrying the allele for black.
They produce a white male lamb that is then backcrossed to
the female parent.
What is the probability of the backcross offspring being black?
Clearly state a) the probability of the F
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 Fall '08
 Eslinger
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