X What does pedigree mean Pedigree a diagram

X What does pedigree mean? Pedigree: a diagram that traces one trait through several generations of a family

= female = male

Example #1 3 How many girls? ___ 2 How many boys? ___ mom daughter #1 dad daughter #2 son

mom dad oldest daughter #1 youngest daughter #2 son

A horizontal line connecting two shapes represents a cross/marriage. mom dad

Example #2 How many crosses/marriages? 2 A C B D E F G

A vertical line extending down from a marriage/cross represents that the couple has children. mom dad

A C B D questions… E F G

Example #3 A C How many couples have children? B D H H G E F M J N P K L O Q ? R S T 4

How do you show twins? A C B D E F

How do you show traits? Shading ( shaded = recessive ) RR Rr rr mutation **A pedigree chart follows one trait.

Rr mom RR dad R = tongue roller r = non-roller Rr son Rr daughter RR daughter R RR RR r Rr Rr

A C B D G E F M Practice questions… J N P HH K L O Q R S T

What is wrong with this pedigree chart? This offspring cannot receive 2 recessive genes. This offspring cannot receive 2 dominant genes. This offspring cannot receive 2 recessive genes.

What are possible genotypes for individual W? W R r R RR Rr rr W could be RR (no shading) or Rr (half-shaded) or rr (all shaded).

Pedigree charts help to trace genetic diseases. Most genetic diseases are a recessive gene. Info to help you with page 93 If you have 1 recessive, you are a carrier, but you are not sick. Aa If you have 2 recessive genes, you are sick with the disease. (you are “affected”) aa

4 3 Granddaughter, carrier, 3 rd generation, older sibling Grandson, carrier, 3 rd generation, middle sibling rr Rr 1 7

A person that carries one copy of the disease gene, but it is masked by the dominant trait. (hybrid) 2 U U is further left. This makes U older than V

Genetic Pedigree Answers 4 1. How many children did the first generation have? 2. How many girls did the first generation have? 3. Describe individual Y. A female carrier/hybrid 4. Describe individual Z. A male carrier/hybrid 5. How many children and grandchildren have the disease? 6. What is the genotype of X? Use the letter R/r. 7. What is the genotype of Y? Use the letter R/r. 8. How many children and grandchildren are carriers for the disease? 9. 10. 1. 3 1 rr Rr 7 Shows the dominant trait, but can pass the What is a carrier? recessive gene on to offspring. How many kids did W and his wife have? 2 U Who is older, U or V? It comes first left to right How do you know?