Example Lab Report on Genetic Crosses

In this lab report example, we will explore the principles of genetic crosses using pea plants. By following a structured format, you will gain insights into how to document your experiments effectively.
By Jamie

Introduction

Genetic crosses are a fundamental concept in genetics that allow us to study inheritance patterns. In this example, we will focus on a classic experiment using Mendel’s pea plants to illustrate how to conduct and report on genetic crosses.

Hypothesis

If true-breeding yellow-seeded pea plants (YY) are crossed with true-breeding green-seeded pea plants (yy), then all offspring (F1 generation) will exhibit yellow seeds due to the dominance of the yellow seed trait.

Materials

  • True-breeding yellow-seeded pea plants (YY)
  • True-breeding green-seeded pea plants (yy)
  • Plant pots
  • Potting soil
  • Water
  • Ruler
  • Labels for plants

Methodology

  1. Crossing the Plants:

    • Label two pots: one for yellow seeds (YY) and one for green seeds (yy).
    • Plant seeds from each variety in their respective pots.
    • Water the seeds and place them in a sunny location.

  2. Observation of F1 Generation:

    • After germination, observe the seeds of the first generation (F1) for their color.
    • Record the dominant trait exhibited by the F1 generation.

  3. F2 Generation Cross:

    • Allow the F1 plants to self-fertilize.
    • Collect and observe the seeds of the second generation (F2).

  4. Data Collection:

    • Count and record the number of yellow and green seeds produced in the F2 generation.

Results

F1 Generation:

  • All seeds observed were yellow (100% yellow, 0% green).

F2 Generation:

  • Total seeds collected: 100
  • Yellow seeds: 75
  • Green seeds: 25

Ratio Calculation:

  • Ratio of yellow to green seeds in F2: 3:1

Discussion

The results support the hypothesis, confirming that the yellow seed trait is dominant over the green seed trait. The observed 3:1 ratio in the F2 generation aligns with Mendelian inheritance patterns, demonstrating the principles of segregation and dominance.

Conclusion

This lab report on genetic crosses illustrates the principles of inheritance using pea plants. By documenting the methodology, results, and analysis, we gain a clearer understanding of genetic principles and their real-world applications.