Pedigree Worksheet | PDF | Dominance (Genetics) | Genotype - Free Printable

Problem Analysis and Solution

The provided document contains two pedigree charts, each with specific instructions for interpreting the family history of genetic traits. Below, I will solve the problems step by step for both pedigrees.

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Pedigree 1: Hemophilia

#### Instructions
- Squares represent males.
- Circles represent females.
- Darkened symbols indicate individuals with hemophilia.
- Horizontal lines represent marriages.
- Vertical lines represent offspring.
- The first child is on the left, and the last-born is on the right.

#### Questions and Solutions

##### 1. How many males are there?
- Count all squares in the pedigree.
- Total males: 10 (I-1, II-3, II-4, III-1, III-4, IV-1, IV-2, IV-3, IV-5, IV-6).

Answer: 10

##### 2. How many males have hemophilia?
- Count darkened squares.
- Males with hemophilia: I-2, III-3, IV-1, IV-3.
- Total: 4.

Answer: 4

##### 3. How many females are there?
- Count all circles in the pedigree.
- Total females: 9 (I-2, II-1, II-2, II-5, III-2, III-5, IV-4, IV-7, IV-8).

Answer: 9

##### 4. How many females have hemophilia?
- Count darkened circles.
- Females with hemophilia: III-5.
- Total: 1.

Answer: 1

##### 5. How many marriages are there?
- Count horizontal lines connecting squares and circles.
- Total marriages: 4 (I-1 ↔ I-2, II-3 ↔ II-4, III-1 ↔ III-5, III-4 ↔ III-6).

Answer: 4

##### 6. How many children did the first couple (couple in row I) have?
- Look at the vertical line extending from the marriage line of I-1 and I-2.
- Number of children: 3 (II-1, II-2, II-3).

Answer: 3

##### 7. How many children did the third couple (couple in row III) have?
- Look at the vertical line extending from the marriage line of III-1 and III-5.
- Number of children: 3 (IV-1, IV-2, IV-3).

Answer: 3

##### 8. How many generations are there?
- Count the levels in the pedigree.
- Generations: I, II, III, IV.
- Total: 4.

Answer: 4

##### 9. How many members are there in the fourth generation?
- Count all individuals in level IV.
- Total: 7 (IV-1, IV-2, IV-3, IV-4, IV-5, IV-6, IV-7).

Answer: 7

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Pedigree 2: Huntington's Disease

#### Instructions
- Shaded individuals have Huntington's Disease.
- There are no carriers; individuals either have the disease or do not.
- Dominant or recessive trait analysis required.

#### Questions and Solutions

##### 10. Write the generation numbers (roman numerals).
- Assign roman numerals to each generation:
- Generation I: I-1, I-2
- Generation II: II-1, II-2, II-3, II-4, II-5, II-6
- Generation III: III-1, III-2, III-3, III-4, III-5, III-6

Answer: I, II, III

##### 11. Which members of the family above are afflicted with Huntington's Disease?
- Identify shaded individuals.
- Afflicted individuals: I-1, II-2, II-5, III-3, III-5.

Answer: I-1, II-2, II-5, III-3, III-5

##### 12. Is Huntington's Disease caused by a dominant or recessive trait?
- Since there are no carriers and the disease skips generations, it is likely dominant.
- Dominant traits are expressed even if inherited from only one parent.

Answer: Dominant

##### 13. How many children did individuals I-1 and I-2 have?
- Count the vertical line extending from the marriage line of I-1 and I-2.
- Number of children: 6 (II-1, II-2, II-3, II-4, II-5, II-6).

Answer: 6

##### 14. How many girls did II-1 and II-2 have?
- Identify the children of II-1 and II-2.
- Children: III-1, III-2, III-3.
- Girls: III-2.
- Total girls: 1.

Answer: 1

##### 15. How many have Huntington's Disease?
- From the previous answer, the afflicted individuals are: I-1, II-2, II-5, III-3, III-5.
- Total: 5.

Answer: 5

##### 16. How is individual III-2 related to II-4 and III-5?
- III-2 is the daughter of II-1 and II-2.
- II-4 is the sister of II-2.
- III-5 is the daughter of II-4 and II-6.
- Therefore, III-2 is the cousin of III-5 and the niece of II-4.

Answer: Cousin and Niece

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

| Individual | Genotype |
|------------|----------|
| I-1 | \( HH \) |
| I-2 | \( hh \) |
| II-1 | \( Hh \) |
| II-2 | \( HH \) |
| II-3 | \( hh \) |
| II-4 | \( hh \) |
| II-5 | \( HH \) |
| II-6 | \( hh \) |
| III-1 | \( Hh \) |
| III-2 | \( hh \) |
| III-3 | \( HH \) |
| III-4 | \( hh \) |
| III-5 | \( Hh \) |
| III-6 | \( hh \) |

Answer: See table above.

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Final Answers Summarized

#### Pedigree 1: Hemophilia
1. Males: 10
2. Males with hemophilia: 4
3. Females: 9
4. Females with hemophilia: 1
5. Marriages: 4
6. Children of first couple: 3
7. Children of third couple: 3
8. Generations: 4
9. Fourth generation members: 7

#### Pedigree 2: Huntington's Disease
10. Generations: I, II, III
11. Afflicted individuals: I-1, II-2, II-5, III-3, III-5
12. Trait type: Dominant
13. Children of I-1 and I-2: 6
14. Girls of II-1 and II-2: 1
15. Individuals with Huntington's Disease: 5
16. Relationship: Cousin and Niece
17. Genotypes: See table above.

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