1 Genetic pedigrees are like family trees They

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Genetic pedigrees are like family trees. • • • They show phenotypes, but also can show hidden traits throughout a genotypes. Phenotypes are used to infer genotypes on a pedigree. Autosomal genes show different patterns on a pedigree than sex-linked genes. 2

Genetic pedigrees • Okay, here are some general rules to keep in mind when creating a pedigree: 1. = Males If you don’t know the sex or it isn’t given you use a triangle. 2. = Females 3. / = Shaded = expresses the trait (usually a disease). 3

Genetic Pedigrees Circles/squares are half shaded or dotted to represent carriers (heterozygous individuals). Note: Carriers of recessive diseases/disorders are considered HEALTHY and don’t express the disease or disorder. * Draw a half shaded and note carrier 4

Genetic Pedigrees • Lets create a simple pedigree. . Using PKU: • PKU (phenylketonuria) is a recessive disorder (healthy is dominant) where sufferers don’t make a protein needed to properly digest certain foods • It can lead to brain damage or be fatal if untreated 5

Creating a pedigree * Lets start with a key: H = Healthy h = PKU 6

Creating a pedigree (cont. ) 1. Manny and Rosa are married and both are healthy. 7

Creating a pedigree (cont. ) 2. They have 3 children. 3. Their oldest child, Jacob, has a recessive disorder called PKU. 8

Creating a pedigree (cont. ) 4. Their middle child Erica and their youngest Matthew are healthy. 5. Now, If healthy is dominant to PKU, fill in the missing genotypes. (start with what you know). 9

Creating a pedigree (cont. ) • We know Jacob has PKU, so he is hh. hh • Now, work backwards for the rest… If Jacob is hh, then he has to have gotten one of each allele from each parent. H h Since Manny and Rosa are healthy, it is safe to say they are heterozygous. H h hh 10

Creating a pedigree (cont. ) • By finishing the punnett sqaure, we know that the other 2 children could be either homozygous dominant or heterozygous. H h • You should have something H HH Hh like this… Hh hh Hh H? h Hh hh H? 11

The next generation 6. Erica meets Moe in college and the two become married (add to your pedigree). 7. Erica and Moe have 2 daughters (add this to your pedigree). 8. Their youngest daughter, Jaime, shows signs of PKU, while Aimee does not (add to pedigree). 9. Fill in the genotypes of the four individuals…starting with what you know. 12

The Next Generation Key H = Healthy h = PKU Hh H? Hh hh This is what you should have! Woo-hoo! 13

Pedigrees Continued… • This family has a history of sickle cell disease in their family • Fill in the genotypes of every person in this family • Hint: make a key, start with what you know (the shaded shapes) and label the genotypes you know 14

Sickle cell anemia (recessive) pedigree Use the key and fill out this pedigree Hint: 3 unknown Key H = Healthy h = Sickle cell anemia 15

You should have something that looks like this… Hh H? hh hh Hh Hh H? Key H? H = Healthy h = Sickle cell anemia 16