Genetics News

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Genetics News

• Summary for Exam II- Do it NOW!

• Office hours underutilization

• Problem Set 7 available

• Problem Set 8 available

• Exam I

not available
Our answers and comments on web. Click on Course
at a Glance then Click on Exams Answer Keys
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Topics for Today

• Sex linkage/Sex limitation
• Calculation of probabilities from pedigree
• Extension of Mendelian Genetics - Multiple
  alleles determining one trait - Multiple genes
  determining one trait - Multiple genes with
  additive effect

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Study Question 6
How is the trait inherited?
x
Dd
Dd
Autosomal dominant
Dd
4
Study Question 6
How is the trait inherited?
Dd
Dd
Autosomal dominant
x
Autosomal recessive
dd
Dd
Dd
Dd
Dd
dd
dd
5
Study Question 6
How is the trait inherited?
XDY
XXD
Autosomal dominant
Autosomal recessive
XDY
x
Sex-linked dominant
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Study Question 6
How is the trait inherited?
XXd
Autosomal dominant
Autosomal recessive
XY
XXd
XdY
XXd
XY
Sex-linked dominant
XdY
XdY
Sex-linked recessive
7
Study Question 6
Could it be an autosomal dominant trait limited
to males?
Dd
Dd
Yes
Dd
dd
Dd
dd
Dd
Dd
Dd
8
Study Question 8
What is the probability that IV.1 will get the
disease?
Specify
P(III.2 x III.3 XdY)
XXd
Parse
Solve
P(III.2 is XXd) AND P(III.2 passes Xd)
XXd ?
XY
?
1/2
1/2
XdY ?
AND P(III.3 is XY) AND P(III.3 passes Y)
1
Probability 1/8
1/2
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Multiple Genes/One Trait
Conventional dihybrid cross
Substrate1 Product1 Substrate2
Product2 A
B
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Multiple Genes/One Trait
Dihybrid cross of interacting genes
9 3 3 1 ? ? ? ? 9 7
Substrate1 Substrate2
Product A
B
11
Multiple Genes/One Trait
Dihybrid cross of interacting genes
9 3 3 1 ? ? ? ? 9 7
chorismate compound X
tryptophan M
N
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Study Question 17
You cross a vermilion-eyed fly with a
cinnibar-eyed fly to obtain F1 progeny, then you
cross these progeny to get F2 progeny. What
phenotypic ratio do you expect?
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Study Question 17
Dihybrid cross of interacting genes
Substrate1 Substrate2
Product V
C
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Study Question 17
Dihybrid cross of interacting genes
9 ? ? ? ?
Substrate1 Substrate2
Product V
C
15
Study Question 17
Dihybrid cross of interacting genes
9 3 ? 1 ? ? ?
Substrate1 Substrate2
Product V
C
16
Multiple Genes/One Trait
Dihybrid cross of interacting genes
9 3 3 1 ? ? ? ? 9 3 4
9 3 3 1 ? ? ? ?
Substrate1 Substrate2
Product V
C
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Study Question 19
Conventional dihybrid cross
Pathway where dihybrid cross gives 151 ratio?
Substrate1 Product1 Substrate2
Product2 A
B
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Study Question 19
What kind of genetic situation can you imagine
that would lead to a 151 phenotypic ratio?
9 3 3 1 ? ? ? ?
9 3 3 1 ? ? ? ? 15
1
Substrate1 Product1 Substrate2
Product2 A
B
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Study Question 20
You find corn with kernels in the
ratio Yellow 247 Golden 154 Sickly green
23 Hypothesis?
Hypothesis One gene, multiple alleles AB x CD
1(11)1 121
20
Study Question 20One gene hypothesis
Exp Obs
You find corn with kernels in the
ratio Yellow 247 Golden 154 Sickly green
23 TOTAL 424
212106106424
Unit 424/4 106
21
Study Question 20Two gene hypothesis
You find corn with kernels in the
ratio Yellow 247 Golden 154 Sickly green
23 Hypothesis?
Hypothesis Two genes for one trait AaBb x AaBb
9331
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Study Question 20Two gene hypothesis
Exp Obs
You find corn with kernels in the
ratio Yellow 247 Golden 154 Sickly green
23 TOTAL 424
238.5 26.5 x 9159 26.5 x 6 26.5 26.5
x 1424
Unit 424/16 26.5