Pedigree Worksheet – day 3 - Free Printable

Problem Analysis:

The provided image contains two pedigree charts. The first chart is related to hemophilia, and the second chart is related to Huntington's Disease. We are tasked with analyzing these pedigrees to answer specific questions about inheritance patterns, affected individuals, and relationships.

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Pedigree 1: Hemophilia

#### Key Rules for Hemophilia Pedigree:
1. Square = Male, Circle = Female
2. Darkened Symbol = Affected Individual (Hemophilia)
3. Clear Symbol = Normal Individual
4. Horizontal Line = Marriage
5. Vertical Line = Offspring

#### Questions:
1. How many males are there?
- Count all squares in the pedigree.
- Answer: There are 10 males.

2. How many males have hemophilia?
- Count all darkened squares.
- Answer: There are 4 males with hemophilia.

3. How many females are there?
- Count all circles in the pedigree.
- Answer: There are 7 females.

4. How many females have hemophilia?
- Count all darkened circles.
- Answer: There are 2 females with hemophilia.

5. Marriage Indicators:
- A horizontal line connecting a circle and a square indicates marriage.

6. Children Indicators:
- Vertical lines extending from a horizontal line indicate offspring.
- Short vertical lines branching off indicate multiple children.

a. How many children did the first couple (couple in row I) have?
- The first couple has one child (a male).
- Answer: 1 child.

b. How many children did the third couple (couple in row III) have?
- The third couple has four children (two males and two females).
- Answer: 4 children.

7. Generations:
- Level I represents the first generation.
- Level II represents the second generation, and so on.

a. How many generations are there?
- Count the levels from top to bottom.
- Answer: 4 generations.

b. How many members are in the fourth generation?
- Count all individuals in the bottom row (Level IV).
- Answer: 6 members.

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Pedigree 2: Huntington's Disease

#### Key Rules for Huntington's Disease Pedigree:
1. Shaded Individuals = Affected by Huntington's Disease
2. Unshaded Individuals = Not Affected
3. Dominant or Recessive Trait Determination:
- If an affected individual has unaffected parents, the trait is dominant.
- If an affected individual has unaffected parents, the trait is recessive.

#### Questions:
6. Write the generation on the pedigree (number them).
- Label each level as follows:
- Topmost level: Generation I
- Second level: Generation II
- Third level: Generation III
- Fourth level: Generation IV

7. Which members of the family above are afflicted with Huntington's Disease?
- Identify all shaded individuals.
- Answer: Individuals I-1, II-2, II-3, III-1, III-3, III-4, III-5, and III-6 are afflicted.

8. Is Huntington's Disease caused by a dominant or recessive trait?
- Observe that individual I-1 (affected) has an unaffected parent (I-2). This indicates a dominant trait.
- Answer: Dominant trait.

9. How many children did individuals I-1 and I-2 have?
- Count the number of offspring from the marriage of I-1 and I-2.
- Answer: 3 children.

10. How many girls did II-1 and II-2 have? How many have Huntington's Disease?
- II-1 and II-2 have 2 daughters (III-1 and III-2).
- Only III-1 is shaded (affected).
- Answer: 2 girls; 1 has Huntington's Disease.

11. How are individual II-2 and III-5 related?
- II-2 is the mother of III-5.
- Answer: Mother and daughter relationship.

12. Write the genotypes of each individual on the pedigree.
- Assume the gene for Huntington's Disease is H (dominant allele) and h (recessive allele).
- Affected individuals have at least one H allele.
- Unaffected individuals have genotype hh.

- I-1: Affected → Genotype = Hh
- I-2: Unaffected → Genotype = hh
- II-1: Unaffected → Genotype = hh
- II-2: Affected → Genotype = Hh
- II-3: Affected → Genotype = Hh
- III-1: Affected → Genotype = Hh
- III-2: Unaffected → Genotype = hh
- III-3: Affected → Genotype = Hh
- III-4: Affected → Genotype = Hh
- III-5: Affected → Genotype = Hh
- III-6: Affected → Genotype = Hh

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Final Answers:

1. Males: 10
2. Males with Hemophilia: 4
3. Females: 7
4. Females with Hemophilia: 2
5. a. Children of First Couple: 1
b. Children of Third Couple: 4
6. Generations: 4
7. Members in Fourth Generation: 6
8. Affected Individuals for Huntington's Disease: I-1, II-2, II-3, III-1, III-3, III-4, III-5, III-6
9. Dominant or Recessive: Dominant
10. Children of I-1 and I-2: 3
11. Girls of II-1 and II-2: 2; Affected: 1
12. Relationship between II-2 and III-5: Mother and daughter
13. Genotypes:
- I-1: Hh
- I-2: hh
- II-1: hh
- II-2: Hh
- II-3: Hh
- III-1: Hh
- III-2: hh
- III-3: Hh
- III-4: Hh
- III-5: Hh
- III-6: Hh

Final Answer Boxed:
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\boxed{
\text{See detailed answers above.}
}
\]