Transcript Pedigrees - Cobb Learning

Mind Stretcher 2/11/16
1. Asexual reproduction relates to humans in that
A. none of our body cells reproduce this way.
B. many body cells reproduce this way.
C. the parent cells do not divide.
D. meiosis occurs.
2. How are sex cells different from other human cells?
A. They have more chromosomes.
B. They have half as many chromosomes.
C. They are larger.
D. They have no chromosomes.
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Pedigrees
What is a Pedigree?
• A family tree
• A pedigree is a diagram of family history over
several generations. It uses symbols to represent
people and lines to represent genetic
relationships.
• These diagrams make it easier to visualize
relationships within families, particularly large
extended families.
• Pedigrees are often used to determine the
mode of inheritance (dominant, recessive,)
of genetic diseases.
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Sample Pedigree
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Reading A Pedigree
• Squares represent males.
• Circles represent females.
• Horizontal lines connecting a male and
female represent a marriage.
• Vertical lines extending downward
from a couple represent their children.
• Oldest individuals are found at the top
of the pedigree.
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Lets look again.
• How many males?
• How many females?
• How many generations?
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Purpose
• The purpose of a pedigree is to analyze
the pattern of inheritance of a particular
trait.
• The symbol of all individuals that possess
this trait are shaded in.
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Dominant or Recessive Traits
•
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Determine whether the disorder is
dominant or recessive.
– If the disorder is dominant, one of the
parents must have the disorder.
– If the disorder is recessive, neither
parent has to have the disorder
because they can be heterozygous.
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Example of Pedigree Charts
• Dominant or Recessive?
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Dominant!!
Because one parent
carries the
trait.
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Dominant or Recessive
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Recessive.
Because neither parent
carries the disorder.
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