Understanding the Law of Dominance in Class 10 Biology
When studying genetics in Class 10 Biology, one of the fundamental concepts is the law of dominance. This law explains the inheritance patterns of traits from parents to offspring. Let’s delve into a simple definition of the law of dominance and explore its implications.
What is the Law of Dominance?
The law of dominance states that in a heterozygous genotype, one allele will be dominant and the other recessive. The dominant allele will express its trait, while the recessive allele remains hidden. This means that only the dominant allele will be observed in the phenotype of an individual.
Examples of the Law of Dominance
One classic example of the law of dominance is the inheritance of seed shape in pea plants studied by Gregor Mendel. When a plant with round seeds (RR) is crossed with a plant with wrinkled seeds (rr), all the offspring have round seeds. This is because the allele for round seeds (R) is dominant over the allele for wrinkled seeds (r).
Another example is the inheritance of flower color in snapdragons. When a red-flowered plant (RR) is crossed with a white-flowered plant (rr), all the offspring have red flowers. The allele for red flowers (R) is dominant, while the allele for white flowers (r) is recessive.
Case Studies on the Law of Dominance
In humans, the law of dominance can be observed in traits like attached or detached earlobes. The allele for attached earlobes is dominant, while the allele for detached earlobes is recessive. If both parents have attached earlobes but carry the recessive allele, their offspring could have detached earlobes.
Similarly, the inheritance of widows peak hairline is governed by the law of dominance. The allele for widows peak is dominant, while the allele for straight hairline is recessive. A person with a widows peak allele will express the trait, even if they also carry the recessive allele for a straight hairline.
Implications of the Law of Dominance
Understanding the law of dominance is crucial in predicting the outcomes of genetic crosses and inheritance patterns. It helps in determining the likelihood of traits being passed down from parents to offspring and contributes to our knowledge of genetic variation in populations.
Conclusion
The law of dominance is a fundamental concept in genetics that governs the expression of traits in organisms. By grasping this principle, Class 10 students can unravel the mysteries of inheritance and genetic diversity in living organisms.
