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

= female = male

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

mom dad oldest youngest daughter #1 daughter #2 son

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

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

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

A B C D E F questions… G

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

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

**A pedigree chart follows one trait. How do you show traits? Shading ( shaded = dominant ) 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 R R r RR RR Rr Rr

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

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

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

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

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