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)

Modes of Inheritance see purple pages 15, 16 Autosomal Recessive Sex Linked 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) Males mostly affected Males inherit sex- linked trait from mothers Girls must have affected fathers

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

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 Madness!! Jason and Amy want to start a family, but are concerned about a genetic disorder called Zitmania which afflicts some of the members of each of their families. Jason is 27 years old, and Amy is 25, and neither one of them have the disorder. They gathered the following info about each of their respective family members and sat around a camp fire one night while on a hiking trip in Jasper. They decided to use their knowledge of pedigree analysis to determine the chance of passing on Zitmania to their offspring! They expressed to each other how happy they were that they finished Bio 30!! They felt equipped with the necessary skills to analyze the situation without the help of an expensive genetics counselor!!

Use the info they compiled to draw a pedigree for Jason’s family and one for Amy’s. Determine the mode of inheritance based on these pedigrees and write the genotypes of each family member in the pedigree below the symbol for male and female. Calculate the probability of Jason and Amy having a son who is affected with Zitmania. Calculate the probability of them having a daughter with the disorder.

Jason’s Family Sister (28) – 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

Amy’s Family Brother (37) – affected Brother (37) – unaffected Mother (56) – unaffected Father (58) – affected Maternal brother (46) – unaffected Maternal brother’s wife (43) – affected Maternal brother’s daughter (19) – unaffected Maternal grandmother (89) – unaffected Maternal grandfather (85) - affected Amy

Jason’s Family Amy’s Family X LINKED? AUTO RECESSIVE? AUTO DOMINANT? Jason

Amy and Jason’s Family Probability of affected male or female = ¼ * ½ = 1/8 Zz ? XZYXZY XZXzXZXz ? XZXZ XzXz XZXZ Y XZXZXZXZ XZXzXZXz XZYXZY XzYXzY ? ? Z z Z z ZZ Zz zz Probability of affected male = 1/2 * 1/2 = 1/4. Female = 0. Autosomal Recessive Sex Linked

Amy and Jason’s Family Probability of affected male or female = 0 X 1/2 = 0 zz ? ? z z z z Autosomal Dominant

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 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 Blue: page 33 – 36 Pedigree sheet