Human Genetics – Part II (Pedigree Notes)
A ______is a chart that shows how a trait, and the genes that control it, are inherited in a family. You can trace the presence of certain traits in your own family by using this chart.
A pedigree shows the ______between parents and children over the generations and how a trait is passed down from one generation to the next. A ______trait is one that (if present) always appears in a persons’ phenotype (physical appearance), but a ______trait is one that only shows if both parents contribute the affected gene.
In a pedigree chart, certain ______indicate sex and colors signify whether or not they carry the trait or show the trait.
A *circle* represents a ______.
A *square* represents a ______.
A *horizontal* line between 2 people indicates ______.
A *vertical* line extending from a marriage line indicates the ______from the couple.
A *fully* shaded shape represents a person who ______the trait in their phenotype.
A *half* shaded shape represents a person who is a ______of the trait
but does not show the trait. NOTE: some pedigrees don’t indicate carriers (carriers must be ______)
Generations are indicated with ______numerals (I, II) and individuals are marked with Arabic numbers (1, 2).
= sickle cell anemia
Pedigree Questions: this pedigree doesn’t indicate carriers
1. What sex is individual I-2?
2. How many children are in the 2nd generation from the union of I-1 and I-2?
3. What are their sexes?
4. Which individual was married in generation 2?
5. How many daughters are in generation 3?
6. How many sons are in generation 4?
7. List the 3 individuals who were afflicted with sickle cell anemia?
8. Were individuals I-1 and I-2 carriers of sickle cell?
9. How do you know? (Explain your answer to #8)
10. List another carrier of sickle cell anemia.