A Cross Is Performed Between A Bird That Is Homozygous For Red Feathers And A Bird That Is Homozygous For Blue Feathers. Purple Offspring Result Due To Incomplete Dominance. Then, Two Of The Purple Offspring Are Crossed.What Proportion Of The Offspring
Introduction
In the world of genetics, the concept of incomplete dominance is a fundamental principle that helps us understand how different traits are expressed in offspring. In this article, we will explore a scenario where a bird that is homozygous for red feathers is crossed with a bird that is homozygous for blue feathers, resulting in purple offspring due to incomplete dominance. We will then examine the outcome of crossing two of the purple offspring and determine the proportion of offspring that will exhibit the dominant, intermediate, and recessive traits.
Incomplete Dominance
Incomplete dominance is a phenomenon where one allele does not completely dominate the other allele, resulting in a combination of the two traits. This is in contrast to complete dominance, where one allele completely masks the other allele. In the case of bird feathers, the red and blue alleles are incompletely dominant, resulting in a purple color when combined.
Crossing Red and Blue Birds
Let's consider a scenario where a bird that is homozygous for red feathers (RR) is crossed with a bird that is homozygous for blue feathers (bb). The resulting offspring will have a combination of the two alleles, resulting in a purple color (Rb).
| Parent 1 (RR) | Parent 2 (bb) | Offspring (Rb) |
|---|---|---|
| Red | Blue | Purple |
Genotype and Phenotype
The genotype of the offspring is Rb, which means they have one allele for red feathers (R) and one allele for blue feathers (b). The phenotype of the offspring is purple, which is a combination of the two traits.
Crossing Purple Offspring
Now, let's consider a scenario where two of the purple offspring (Rb) are crossed. We want to determine the proportion of offspring that will exhibit the dominant, intermediate, and recessive traits.
Possible Genotypes and Phenotypes
When two purple offspring (Rb) are crossed, the possible genotypes and phenotypes of the offspring are:
| Genotype | Phenotype |
|---|---|
| RR | Red |
| Rb | Purple |
| bb | Blue |
| RB | Purple |
| Bb | Purple |
Proportion of Offspring
To determine the proportion of offspring that will exhibit the dominant, intermediate, and recessive traits, we need to calculate the probability of each genotype.
- RR: 25% (1/4)
- Rb: 50% (2/4)
- bb: 25% (1/4)
Conclusion
In conclusion, when two purple offspring (Rb) are crossed, the proportion of offspring that will exhibit the dominant, intermediate, and recessive traits is:
- Red (RR): 25%
- Purple (Rb): 50%
- Blue (bb): 25%
This demonstrates the concept of incomplete dominance in bird feathers, where the combination of two alleles results in a new trait that is different from the original traits.
References
- [1] "Genetics" by William S. Klug and Michael R. Cummings
- [2] "Biology" by Campbell and Reece
Further Reading
- [1] "Incomplete Dominance" by Khan Academy
- [2] "Genetics of Bird Feathers" by Science Daily
A Cross is Performed between a Bird that is Homozygous for Red Feathers and a Bird that is Homozygous for Blue Feathers. Purple Offspring Result due to Incomplete Dominance. Then, two of the Purple Offspring are Crossed. What Proportion of the Offspring =====================================================
Q&A: Understanding Incomplete Dominance in Bird Feathers
Q: What is incomplete dominance?
A: Incomplete dominance is a phenomenon where one allele does not completely dominate the other allele, resulting in a combination of the two traits. This is in contrast to complete dominance, where one allele completely masks the other allele.
Q: What happens when a bird that is homozygous for red feathers is crossed with a bird that is homozygous for blue feathers?
A: When a bird that is homozygous for red feathers (RR) is crossed with a bird that is homozygous for blue feathers (bb), the resulting offspring will have a combination of the two alleles, resulting in a purple color (Rb).
Q: What is the genotype and phenotype of the purple offspring?
A: The genotype of the purple offspring is Rb, which means they have one allele for red feathers (R) and one allele for blue feathers (b). The phenotype of the purple offspring is purple, which is a combination of the two traits.
Q: What happens when two purple offspring are crossed?
A: When two purple offspring (Rb) are crossed, the possible genotypes and phenotypes of the offspring are:
| Genotype | Phenotype |
|---|---|
| RR | Red |
| Rb | Purple |
| bb | Blue |
| RB | Purple |
| Bb | Purple |
Q: What is the proportion of offspring that will exhibit the dominant, intermediate, and recessive traits?
A: To determine the proportion of offspring that will exhibit the dominant, intermediate, and recessive traits, we need to calculate the probability of each genotype.
- RR: 25% (1/4)
- Rb: 50% (2/4)
- bb: 25% (1/4)
Q: What is the significance of incomplete dominance in bird feathers?
A: Incomplete dominance in bird feathers is significant because it demonstrates how different traits can combine to produce a new trait that is different from the original traits. This concept is important in understanding the genetics of many organisms.
Q: What are some real-world examples of incomplete dominance?
A: Some real-world examples of incomplete dominance include:
- The combination of red and white flowers in certain plant species
- The combination of brown and black fur in certain animal species
- The combination of blue and yellow eyes in certain human populations
Q: How can incomplete dominance be used in agriculture and animal breeding?
A: Incomplete dominance can be used in agriculture and animal breeding to produce new traits that are desirable for human consumption or other purposes. For example, farmers can use incomplete dominance to produce crops with improved disease resistance or animal breeders can use it to produce animals with improved growth rates.
Q: What are some limitations of incomplete dominance?
A: Some limitations of incomplete dominance include:
- The complexity of the genetic system
- The difficulty of predicting the outcome of certain crosses
- The potential for unintended consequences
Conclusion
In conclusion, incomplete dominance is a fundamental concept in genetics that helps us understand how different traits are expressed in offspring. By understanding incomplete dominance, we can better predict the outcome of certain crosses and use it to produce new traits that are desirable for human consumption or other purposes.