Pedigrees Show traits are passed on in a

Pedigrees Show 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)

Modes of Inheritance see purple pages 15, 16 Autosomal Recessive Autosomal Dominant • 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 • Aa or AA = affected • Affected need only have 1 affected parent • Affected (Aa) parents can have unaffected children (aa) Sex Linked • Males mostly affected • Males inherit sexlinked trait from mothers • Girls must have affected fathers

Albinism Must be autosomal recessive. For this condition, affected individuals are homozygous recessive – lack enzyme to produce melanin. Recessive? Dominant? Sex-linked?

Pedigree Analysis What is this pedigree showing?

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

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 Jason

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

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