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Warm Up. Copy the notebook info into your notebook Table of Contents March 19 th 7.L.2.2 Pedigree Notes March 19 th 7.L.2.2 Pedigree How do Pedigrees help determine inheritance of genetic traits and diseases?. Pedigrees. What is a pedigree?
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Warm Up Copy the notebook info into your notebook Table of Contents March 19th 7.L.2.2 Pedigree Notes March 19th 7.L.2.2 Pedigree How do Pedigrees help determine inheritance of genetic traits and diseases?
Pedigrees What is a pedigree? -Pedigrees are family trees which show which individuals in the family get certain diseases or have certain traits.
Why are pedigrees important? Scientists use pedigrees to track/trace the passing on of genes and traits over generations. Pedigrees help determine how genetic diseases are passed through families
Pedigrees show generationsEach row represents a generation Generation 1 Generation 2 Generation 3
Pedigrees Show Marriage/ MatingA horizontal line connecting a circle and a square means the male and female are “married”
Pedigrees show childrenVertical Line connect parents and children Parents Children
Pedigrees shown Genotypes / Affectednessshaded / colored = has traita colored in shape always has the recessive traitunless otherwise statedTwo lower cases in genotype
Clear shape = homozygous dominant genotype Heterozygous if child is colored in Genotype written as E? (letter and ?)
Shaded = homozygous recessive Half = heterozygous Clear = Homozygous Dominant or Heterozygous (depends on child’s genotype)
Pedigrees show Death Circle or Square with diagonal line means person has died
Rules of Logic for Reading A Pedigree 1. If neither parent show the trait: • a. the trait cannot be dominant. • b. the trait could be recessive and either parent or both could be heterozygous carriers. 2. If one parent shows the trait: • a. the trait could be dominant and the affected parent could be heterozygous while the unaffected parent is not a carrier • b. the trait could be recessive and the affected parent is homozygous while the unaffected parent could be a heterozygous carrier 3. If both parents show the trait: • a. the trait could be dominant and both parents could be heterozygous carriers which • means that some of the children could be unaffected • b. the trait could be recessive meaning that both parents would have to be homozygous and • all the children would have to be affected
Pedigree 1 shows a family of parrots. One of the offspring shows the trait for blue feathers. (R = red feathers, r = blue feathers) • Do you think blue feathers are dominant or recessive? recessive 2. What must the genotypes of the parents be? Rr 3. What two genotypes could the other offspring have? RR or Rr
Father has green leaves • Male = gg, female = Gg • Bb • bb • Bb or BB
Reading a Pedigree • How many males are there? • How many females are there? • How many children did the first • generation parents have? • 4. How many sets of married couples • Does the pedigree show? • How many carriers does the pedigree show? • 6. How many affected individuals does the pedigree show?
How many males are there? • 4 • How many females are there? 5 • 3. How many children did the first • generation parents have? 3 • 4. How many sets of married couples • Does the pedigree show? • 3 • How many carriers does the pedigree show? 0 • How many affected individuals does the pedigree show? 1
Practice • Genetics Pedigree Worksheet #1 > no dimples = dd (colored in = no dimples) #2 > unibrow = ee (colored in = unibrow) #3 > colored in = dd
Warm Up • Put Pedigree HW worksheet on desk • Answer front side of handout (the side that says Warm Up) READ KEY AT THE BOTTOM OF THE PAPER
Colored = FreeBlank = Attached F = Dominant, Free f = Recessive, Attached
How many generations? 3 The chart shows a total of 5 female offspring. How many of these women are carriers of colorblindness? 2 Of the 3 male offspring, how many have colorblindness? 2 Review Exit Ticket
Notes Table of Contents March 20th Pedigree Day 2 Notes March 20th Pedigree Day 2 How do you interpret a pedigree chart?
Identifying People in Pedigrees Roman Number of Generation and then Number in row IV 1 II 7
a. How many males are there? 8 b. How many males have hemophilia? 3 2. A circle represents a female. If it is darkened, she has hemophilia; if open she is normal. a. How many female are there? 8 b. How many females have hemophilia? 2 3. A marriage is indicated by a horizontal line connecting a circle to a square. a. How many marriages are there? 3 4. A line perpendicular to a marriage line indicates the offspring. If the line ends with either a circle or a square, the couple had only one child. However, if the line is connected to another horizontal line, then several children were produced, each indicated by a short vertical line connected to the horizontal line. The first child born appears to the left and the last born to the right. a. How many children did the first couple (couple in row I) have? 2 b. How many children did the third couple (couple in row III) have? 7 5. Level I represent the first generation, level II represents the second generation. a. How many generations are there? 4 b. How many members are there in the fourth generation? 7
I II III 6. Write the generation on the pedigree numbers (roman numerals). 7. Which members of the family above are afflicted with Huntington’s Disease? I-1, II-2, II-3, II-7, III-3 8. There are no carriers for Huntington’s Disease- you either have it or you don’t. With this in mind, is Huntington’s disease caused by a dominant or recessive trait? dominant 9. How many children did individuals I-1 and I-2 have? 6
10. How many girls did II-1 and II-2 have? 2 How many have Huntington’s Disease? 2 11. How is individual III-2 and II-4 related? niece-uncle I-2 and III-5? grandma-grandson 12. Write the genotypes of each individual on the pedigree.
I II III IV 13. Write the generation on the pedigree numbers (roman numerals). The pedigree to the above shows the passing on of Hitchhiker’s Thumb in a family. Is this trait dominant or recessive? recessive 14. How do you know? Because parents III-4 and III-5 had to have kids IV-2 and IV-4 15. How are individuals III-1 and III-2 related? mating 16. Name 2 individuals that have hitchhiker’s thumb. IV-2 and IV-4 17. Name 2 individuals that were carriers of hitchhiker’s thumb. III-4 and III-5 18. Write the genotypes for each individual on the pedigree.
19 • a. Which characteristic is dominant? Black • b. Which characteristic is recessive? White • c. Determine the genotypes of all individuals. You will have three “A?”. Write your Genotypes beneath each individual.
Interpreting a Pedigree Generations - Each row represents a generation. • Each generation is marked using Roman Numerals • (I, II, III, IV)
Interpreting a Pedigree On a pedigree the trait is shown by the colored shapes Generally if a shape is colored that person has the trait
Parent Genotype Based on Child If one or more child has the trait AND Parent shapes are blank Parent genotype = heterozygous
Determining if the trait is Dominant or Recessive • If one parent has disorder (colored) disorder is dominant • If neither parent has to have the disorder (blank) but children do, the disorder is recessive and parents are heterozygous.
Parent with disorder (colored in) = dominant Parent without disorder (blank) = recessive
Dominant Or Recessive? Dominant because The father has it
Dominant or Recessive Recessive because parents do not have it
Dominant or Recessive? Recessive because parents do not have it
Dominant or Recessive? Dominant because one parent has it
Practice Problem 1 and Problem 2
Problem 1 • I , II 1, II3, II 7, III3 • Dominant • 6 • 2 Huntington's = 1 • Uncle Grandmother1
Problem 2 • Recessive • Because the parents do not have it • Married • IV 1, IV3 • III 1, III 2
Problem 3 Create a pedigree for the following: 1. Joe Marries Sue- they are carriers for the jumping disease 2. They have 4 kids: Jack, Zack, Luke and Sara 3. Zack and Sara have the jumping disease (recessive) 4. Jack marries Amy, she has the disease 5. They have Lorie, who is also affected 6. Sara marries Dan who is a carrier. Sara is pregnant