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Pedigrees

Pedigrees. Pedigrees. Show how traits are passed on in a family. Female. =. Male. =. See purple booklet after page 16 OR blue page 57 for pedigree symbols (these are on your diploma exam data sheet). Line down from a horizontal line indicates offspring.

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Pedigrees

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  1. Pedigrees

  2. Pedigrees Show how traits are passed on in a family Female = Male = • See purple booklet after page 16 OR blue page 57 for pedigree symbols (these are on your diploma exam data sheet). • Line down from a horizontal line indicates offspring. • Oldest offspring always on the left • Affected individuals are shaded in • Heterozygous individuals half shaded in (sometimes)

  3. Modes of Inheritancesee purple pages 15, 16 Sex Linked Autosomal Dominant Autosomal Recessive • Males mostly affected • Males inherit sex-linked trait from mothers • Girls must have • affected fathers • Aa or AA = affected • Affected need only • have 1 affected parent • Affected (Aa) parents can have unaffected children (aa) • aa = affected • May skip 1 or more • Generations (recessive trait hidden for generations) • 2 unaffected may have affected • 2 affected will have all children affected for more details see - Blue booklet: pages 54, 55

  4. HINT: what do these symbols mean? Albinism not dominant Must be autosomal recessive. For this condition, affected individuals are homozygous recessive – lack enzyme to produce melanin. Recessive? Dominant? Sex-linked?

  5. Pedigree Analysis What is this pedigree showing?

  6. Why is inbreeding not recommended? Chance of recessive condition showing up in offspring is increased!

  7. Jason Lets’ draw a pedigree for Jason’s family • Sister (28) – unaffected • Jason (27) - unaffected • Brother (25) – affected • Identical twin brothers (18) – unaffected • Mother (46) – unaffected • Father (45) – affected • Paternal sister (43) – affected • Paternal grandmother (77) – unaffected • Paternal grandfather (79) - affected

  8. Pedigree Questions Today • Go to…purple - after page 16 – page 2 (Tay-Sachs disease)… • orange page 48 – 50 • Together: start page 51… All pedigree questions: • Purple: page 2 – 5 (after page 16) • Orange: pages 48 - 55 • Blue: page 33 – 36

  9. All X-linked Questions: • Orange: pages 36 – 41 • Blue: page 48 All pedigree questions: • Purple: page 2 – 5 (after page 16) • Orange: pages 48 - 55 • Blue: page 33 – 36 • Pedigree sheet

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