Topic 12 pt 1: Pedigree analysis Flashcards

1
Q

Why are humans terrible organisms to study from a genetics perspective

A
  • can’t selectively mate
  • too few offspring
  • long generation time
  • few discrete traits
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2
Q

What is a pedigree

A

Pictorial representation of a family history; a family tree that outlines the inheritance of one or more characteristics

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3
Q

What is a proband

A

The person from whom the pedigree is initiated

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4
Q

Slide 6***

A

Pedigree symbols

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5
Q

What should we keep in mind when carrying out a pedigree analysis

A
  1. Genetic disorders are rare
  2. Mendelian ratios are rarely seen
  3. Non-family members are assumed to be homozygous normal (WT)
  4. Recessive disorders more common (not phenotypically visible; het)
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6
Q

What is the different between a disorder and a variant

A

Disorder = individuals are affected or not affected
Variants = more common

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7
Q

What are the four key observations made when doing pedigree analysis

A
  1. Are the affected individuals in each generation
  2. Are there sex-differences between affected individuals
  3. Is there male to male transmission
  4. Do unaffected parents have affected offspring
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8
Q

Slide 8***

A

important

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9
Q

Characteristics of an autosomal recessive trait

A
  • appears in both sexes equally
  • skips generations
  • affected offspring born to unaffected parents
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10
Q

Answers to four questions in autosomal recessive trait

A
  1. No (recessive)
  2. No (autosomal)
  3. Not sure
  4. Yes (recessive)
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11
Q

Example of autosomal recessive trait. Describe it

A

Cystic fibrosis
- common, fatal
- build-up of mucus in the lungs
- digestive problems

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12
Q

Characteristics of an autosomal dominant trait

A
  • both sexes equally
  • both sexes transmit to offspring
  • does not skip generations
  • affected offspring have affected parent
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13
Q

Example of autosomal dominant trait

A

Hereditary dwarfism (achondroplasia)

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