Analyze data
Reciprocal crosses in a fly
- Unit 5
- 4 points
- About 10 minutes
You can use a calculator on this question, just like on exam day.
A short question with data in a table or graph. You describe what the data show, use the data to judge a hypothesis, and explain how the results connect to biology you know. On the exam: Question 6 of 6 in Section II; about 10 minutes suggested.
The question and its sources
In a species of fly, females have two X chromosomes and males have one X and one Y chromosome. Wings are either gray or yellow. Researchers did two reciprocal crosses using true-breeding flies. In Cross 1, gray-winged females were mated with yellow-winged males. In Cross 2, yellow-winged females were mated with gray-winged males. They recorded the wing color and sex of the offspring (Table 1).
Table 1. Offspring of two crosses
| Cross | Gray-winged females | Yellow-winged females | Gray-winged males | Yellow-winged males |
|---|---|---|---|---|
| Cross 1: gray female × yellow male | 52 | 0 | 49 | 0 |
| Cross 2: yellow female × gray male | 51 | 0 | 0 | 47 |
Source: Hypothetical data
Suggested time: 10 minutes
Your answers are saved in this browser as you type.
Part (a)
1 pointBased on Table 1, identify the dominant wing color, and support your answer with data from Cross 1.
0 / 2,500 characters
Part (b)
1 pointBased on Table 1, describe how the wing color of the male offspring in Cross 2 differs from that of the male offspring in Cross 1.
0 / 2,500 characters
Part (c)
1 pointA student claims that the gene for wing color is on an autosome. Use the data to evaluate the student's claim.
0 / 2,500 characters
Part (d)
1 pointExplain why all of the male offspring in Cross 2 had yellow wings.
0 / 2,500 characters
Checking scoring…
Scoring it yourself shows you the rubric, examples and a model answer. Try writing your answer first.