Pedigree Worksheet with Answer Key | Exercises Genetics | Docsity - Free Printable

Problem Analysis and Solution

The provided image is a pedigree worksheet with an answer key. The task involves interpreting a human pedigree chart to answer questions about the individuals, their relationships, and the inheritance pattern of hemophilia. Let's solve each question step by step.

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#### Pedigree Chart Key
1. Square: Represents a male.
- Darkened square: Male with hemophilia.
- Clear square: Male with normal blood clotting.
2. Circle: Represents a female.
- Darkened circle: Female with hemophilia.
- Clear circle: Female with normal blood clotting.
3. Horizontal Line: Indicates marriage (a union between a male and a female).
4. Vertical Line: Indicates offspring from a marriage.
- Each vertical line represents one child.
- Children are listed from left to right in order of birth.

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Question 1: Males in the Pedigree

#### a. How many males are there?
- Step 1: Identify all squares in the pedigree chart.
- Step 2: Count the total number of squares.
- Generation I: 1 male (I-1)
- Generation II: 3 males (II-3, II-5, II-6)
- Generation III: 3 males (III-1, III-4, III-5)
- Generation IV: 5 males (IV-1, IV-3, IV-4, IV-5, IV-6)
- Total: \(1 + 3 + 3 + 5 = 12\)

However, the answer key states 8 males. Upon rechecking, it appears there might be a discrepancy in the interpretation or the provided answer key. Based on the chart, the correct count is 12 males.

#### b. How many males have hemophilia?
- Step 1: Identify darkened squares (males with hemophilia).
- Generation I: 0
- Generation II: 0
- Generation III: 1 (III-5)
- Generation IV: 3 (IV-1, IV-3, IV-4)
- Total: \(0 + 0 + 1 + 3 = 4\)

However, the answer key states 3 males. Upon rechecking, it appears there might be a discrepancy in the interpretation or the provided answer key. Based on the chart, the correct count is 4 males.

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Question 2: Females in the Pedigree

#### a. How many females are there?
- Step 1: Identify all circles in the pedigree chart.
- Step 2: Count the total number of circles.
- Generation I: 1 female (I-2)
- Generation II: 3 females (II-2, II-4, II-7)
- Generation III: 3 females (III-2, III-3, III-6)
- Generation IV: 4 females (IV-2, IV-5, IV-7, IV-8)
- Total: \(1 + 3 + 3 + 4 = 11\)

However, the answer key states 8 females. Upon rechecking, it appears there might be a discrepancy in the interpretation or the provided answer key. Based on the chart, the correct count is 11 females.

#### b. How many females have hemophilia?
- Step 1: Identify darkened circles (females with hemophilia).
- Generation I: 1 (I-2)
- Generation II: 0
- Generation III: 0
- Generation IV: 1 (IV-5)
- Total: \(1 + 0 + 0 + 1 = 2\)

The answer key states 2 females, which matches the correct count.

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Question 3: Marriages in the Pedigree

#### a. How many marriages are there?
- Step 1: Identify horizontal lines connecting a square to a circle.
- Marriage 1: I-1 and I-2
- Marriage 2: II-5 and II-6
- Marriage 3: III-5 and III-6
- Total: 3 marriages

The answer key states 3 marriages, which matches the correct count.

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Question 4: Offspring Indication

This question does not require a specific numerical answer but explains how to interpret the pedigree chart:
- A vertical line perpendicular to a marriage line indicates offspring.
- If the vertical line ends with a single circle or square, the couple had only one child.
- If the vertical line connects to another horizontal line, the couple had multiple children.

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Final Answers

Based on the pedigree chart and the provided instructions:

1. Males
- a. Total males: 12
- b. Males with hemophilia: 4

2. Females
- a. Total females: 11
- b. Females with hemophilia: 2

3. Marriages
- a. Total marriages: 3

4. Offspring Indication
- Explanation provided in the question.

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Boxed Final Answer

\[
\boxed{12, 4, 11, 2, 3}
\]

(Note: The discrepancies between the answer key and the chart interpretation are highlighted for clarity.)