Practice Pedigrees! Try them out! A shape with a dot in the center denotes a ‘carrier’
Are you ready for some Pedigrees?!?! • Before we move on any questions regarding Punnett Squares?
What are Pedigrees? • A pedigree is a diagram of family relationships that uses symbols to represent people and lines to represent genetic relationships. • Pedigrees are often used to determine the mode of inheritance (dominant, recessive, etc.) of genetic diseases. • Autosomal: Refers to chromosomes that are NOT sex chromosomes (xx or xy).
Anatomy of a Pedigree Circle= FemaleSquare= Male A line connecting a square and a circle implies they “mated.” Probably in the early afternoon. If a circle or square is darkened, that means has a particular trait or suffers from a disease/disorder.
Different Modes of Inheritance: 1.) Autosomal Dominant • Diseases or traits that exhibit an Autosomal Dominant inheritance pattern follow the following rule:A = the trait (a genetic disease or abnormality, dominant) a = normal (recessive) • Examples of autosomal dominant disorders: Achondroplasia, pseudoachondroplasia, the multiple epiphyseal dysplasias, chondrodysplasias, osteogenesis imperfecta, Marfan syndrome, polydactyly, hereditary motor sensory neuropathies I and II (Charcot-Marie-Tooth disease), myotonic dystrophy, and neurofibromatosis.
Are these both examples of Autosomal Dominant Pedigrees? B A Explain your answer! What are the genotypes in pedigree B?
Quick Review Question! You know you love it! • What can you conclude from these two examples about the parents of a person that has a dominant characteristic? • A.)If a person has a dominant trait, the parents will not have the trait. B.)If a person has a dominant trait, the parents might have the trait or they might not have it. C.) If a person has a dominant trait, at least one of the parents will have the trait. D.)If a person has a dominant trait, both of the parents will have the trait.
Another Example: Aww Yea!! What are the genotypes in this pedigree?
Quick Review Questions: The Adventure Continues! • 1.) Is it possible that this pedigree is for an autosomal dominant trait? • 2.) Can two individuals that have an autosomal dominant trait have unaffected children? A.)If two individuals have a dominant trait, none of their offspring will have the trait. B.)If two individuals have a dominant trait, their offspring might or might not have the trait. C.)If two individuals have a dominant trait, their offspring will have the trait.
Different Modes of Inheritance: 2.) Autosomal Recessive • Diseases or traits that follow Autosomal Recessive inheritance patterns:A = normal a = the trait (a genetic disease or abnormality) • Examples of Autosomal Recessive diseases: Cystic fibrosis, sickle cell anemia (We will study this very soon), and Tay Sachs disease.
Guess what: More Pedigrees! • Assuming that the trait is recessive, write the genotype of each individual next to the symbol. Is this an example of an Autosomal Recessive Pedigree?
What About this one? Assuming the disorder is recessive, is this an example of an Autosomal Recessive pedigree? Write in the Genotypes for each individual.
Quick Review Question: Great things come in 3’s • 1.) If a trait is autosomal recessive, what can you conclude about the children if both parents are affected? • A.) If both parents are affected, none of the children will be affected.B.)If both parents are affected, the children might or might not be affected. C.)If both parents are affected, all of the children will be affected.
Hmm, what about this one? Is it possible that this pedigree is for an autosomal recessive trait? What are the Genotypes for these individuals?
Quick Review Question: • If a trait is autosomal recessive, what can you conclude about the children of two parents that are not affected? • A.) If two parents have a dominant trait, the children will not have the trait. B.) If two parents have a dominant trait, the children might or might not have the trait. C.) If two parents have a dominant trait, the children will have the trait.
Challenge Question 1 Assign Genotypes as usual. Can this pedigree possible represent an Autosomal Recessive disease? What does this pedigree infer about recessive traits?
Different Modes of Inheritance: 3.) X-Linked Recessive • The sex of an individual has been linked to certain disorders, we’ll finish by examining these pedigrees. • New NomenclatureXA= normal Xa = the trait (a genetic disease or abnormality) Y = Y chromosome (males only) • Examples for a Female: XAXa, XAXA, XaXaWhat would the male sex genotype look like? • Examples for Males: XAY, XaY
Let’s Practice Assign the genotypes (Use X and Y’s now). Is it possible that the pedigree above is for an X-linked recessive trait?
Keep Going, almost there! Is it possible that these pedigrees represent an X-linked recessive trait? Assign the genotypes (Use X and Y’s now).
Last Quick Review Questions! • What can you conclude about the children of mothers affected with an X-linked recessive trait: If the mother has an X-linked recessive trait, the children will not have the trait. A. )If the mother has an X-linked recessive trait, the children might or might not have the trait. B.) If the mother has an X-linked recessive trait, all of the children will have the trait. C.) If the mother has an X-linked recessive trait, females will have the trait but males will only have the trait if their father also has the trait. D.) If the mother has an X-linked recessive trait, males will have the trait, but females will only have the trait if their father also has the trait.
Last Quick Review Questions! A New Hope! • What can you conclude about the father of an affected female? • A.)The father of an affected female will not be affected. B.) The father of an affected female might or might not be affected. C.)The father of an affected female will be affected. Why is this so? Let’s Explore that tomorrow!
Homework! • Create a simple Pedigree of your own family! • Figure out whether a trait (eye color, hair color, a disease) has an autosomal dominant or autosomal recessive behavior. • 2 Generations are requiredbut 3 would be best. • Due Thursday! Example
Solution! Ehf EhF eHF ehF EHF ehf EHF EEHHFF EhF Ehf eHF ehF ehf Fill in the rest of the table and interpret the data!
Question of the Day! What makes a family a family? When does a immediate family stop and an ancestry begin?
We Are Family! Introduction to Dihybrid Crosses and Pedigree Genetics Mr. NicholsPHHS
Introduction Problems • In summer squash, white fruit color (A) is dominant over yellow fruit color (a) and disk-shaped fruit (D) is dominant over sphere-shaped fruit (d).If a white homozygote squash with Heterozgous disk-shaped fruit is crossed with a yellow, sphere-shaped fruit, what will the phenotypic and genotypic ratios be for:
Try this one on your own! • In the deep rainforests of Brazil lives the Ocamazi tribe, amongst the members of this tribe exists a dominant trait for webbed feet (F), most have this trait, those that don’t have non-webbed feet (f). Additionally most members of this tribe webbed hands(W), a small minority have normal non-webbed fingers (w). Needless to say this tribe is great at swimming. • Problem: An Ocamazi princess Heterozygous for both webbed feet and fingers travels to another tribe to meet her soon to be husband, his tribe also has webbed feet which is also heterozygous for but no webbed hands which he is homozygous for. Draw the cross for the mating of these two people.
Solution • Princess: FfWw Husband: Ffww Fw fw Fw fw Interpret this data! FW FFWw FFWw FfWw FfWw FFww Ffww Fw FFww Ffww ffWw ffWw fW FfWw FfWw fw Ffww ffww ffww Ffww F-Webbed Feet, f-Non Webbed FeetW- Webbed hands, w-Non Webbed hands
Challenge Problem • You are a world-famous breeder of Purple-People Eaters. Tragically, your entire stock perishes in a fire except for two individuals. They are both heterozygous for all three traits desired. The three traits are as follows: Traits • EE or Ee=Two eyes ee= One eye • HHorHh= Twohornshh= One horn • FF or Ff= Non-flying ff= Flying
HAPPY FRIDAY, GET YOUR NOTES OUT IN PREPARATION FOR AMAZING THINGS TO COME!!!
Solve the following Pedigree by assigning genotypes and determining the mode of inheritance.