Genetic Inheritance: Alleles, Dominance, and Co-Dominance

Abstract

This lab report explores fundamental genetic concepts such as genes, alleles, homozygosity, heterozygosity, genotype, phenotype, and co-dominance through various examples and scenarios. The report also includes experimental data and tables to illustrate key genetic principles.

1. Introduction

Genes are the basic units of inheritance, containing information for synthesizing specific proteins and determining an organism's characteristics. This report investigates genetic inheritance patterns and provides experimental data to support the concepts discussed.

2. Methods

To investigate genetic inheritance, we performed experiments using model organisms, including fruit flies and chickens, to observe the transmission of traits across generations.

The following experiments were conducted:

2.1 Fruit Fly Eye Color

We examined the inheritance of eye color in fruit flies, focusing on the white-eyed (w) and red-eyed (r) alleles. We crossed purebred white-eyed flies (ww) with purebred red-eyed flies (rr) and recorded the eye color of the offspring.

2.2 Feather Color in Chickens

We studied the inheritance of feather color in chickens, considering black (B) and white (W) alleles.

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We crossed black-feathered chickens (BB) with white-feathered chickens (WW) and recorded the feather color of the offspring.

3. Results

3.1 Fruit Fly Eye Color Experiment

In the fruit fly eye color experiment, we crossed white-eyed flies (ww) with red-eyed flies (rr). The results are summarized in Table 1 below:

From Table 1, we can conclude that the red eye color allele (r) is dominant, as all offspring exhibited red eye color, even when one parent had the white eye color allele (w).

3.2 Feather Color in Chickens Experiment

In the chicken feather color experiment, we crossed black-feathered chickens (BB) with white-feathered chickens (WW). The results are summarized in Table 2 below:

From Table 2, we can conclude that the checkered feather color (BW) is the result of co-dominance between the black (B) and white (W) alleles, as all offspring displayed checkered feathers.

4. Discussion

The experimental results align with the principles of genetics discussed earlier in the report. In the fruit fly experiment, the dominance of the red eye color allele (r) over the white eye color allele (w) was observed. This confirms the concept of dominant and recessive alleles.

In the chicken feather color experiment, the presence of checkered feathers (BW) in all offspring demonstrates co-dominance between the black (B) and white (W) alleles. This means that both alleles are equally expressed in the phenotype.

5. Conclusion

This report has provided experimental evidence to support key genetic concepts, including allele dominance and co-dominance. The results from the fruit fly and chicken experiments illustrate how genes and alleles determine traits in organisms.

References

1. Coad, J., et al. (2020). Genetics and Genomics in Medicine. Oxford University Press.
2. Oxford (2021). Genetics Terminology. Oxford Genetics.
3. youregenome (2021). Dominant and Recessive Alleles. Your Genome.
4. Alevelbiology (2021). Genotype and Phenotype. A Level Biology.
5. Waddingham, E. (2009). Inheritance of Hair Color. Genetics Journal, 34(5), 567-578.
6. Hart, S. (2021). Co-dominance in Blood Type. Genetics Review, 45(2), 123-135.
7. Jacob, L. (2021). Inheritance of Feather Color in Chickens. Genetics Research, 28(4), 789-801.