Non Mendelian Genetics

1
Non Mendelian Genetics

• Co dominant,
• Sex Linked and
• Polygenic Traits

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Codominance Blood Type
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Donors and Recipients
Donor Blood Type Donor Blood Type Donor Blood Type Donor Blood Type
Type A Type B Type AB Type O
Recipient
Type A Y N N Y
Type B N Y N Y
Type AB Y Y Y Y
Type O N N N Y
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Codominance Practice Problems
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Sex-linked Traits

• Colorblindness
• X chromosome,
• recessive

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Sex-linked Practice Problems
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Other Sex-linked Traits

• Duchenne muscular dystrophy
• gene for dystrophin, important structural protein
  in muscle
• Hemophilia
• Inability of blood to clot

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Polygenic Traits

• Most phenotypic traits are the result of
  multiple gene interactions.
• In humans these include
• Hair color
• Skin pigmentation
• Eye color
• Height
• Weight

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Hair Color
At least 4 genes control hair color
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Skin Color
11
The Ultimate Punnett Square
f two  AaBbCc  people would get married and have
children, the Punnett square would look like
this
If two heterozygous individuals (AaBbCc) have a
child, what is the probably that their child will
be very dark skinned?
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Eye Color in Humans

• More than 6 genes control eye color
• Two genes on Chromosome 15 account for most of
  the eye color combinations

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Genetics Problem Practice