What are Mendel’s three laws of inheritance, and how did he arrive at these principles?
The Correct Answer and Explanation is :
Mendel’s three laws of inheritance, which form the foundation of classical genetics, are:
- Law of Segregation: This law states that every individual has two alleles for each gene (one inherited from each parent), and these alleles separate or segregate during gamete formation. As a result, each gamete carries only one allele for each gene. When gametes combine during fertilization, the offspring inherit one allele from each parent.
- Law of Independent Assortment: According to this law, the alleles for different traits segregate independently of one another during gamete formation. This means that the inheritance of an allele for one trait does not affect the inheritance of an allele for another trait, assuming the genes are located on different chromosomes or are far apart on the same chromosome.
- Law of Dominance: This law states that when two different alleles for a gene are present in an individual, one allele may mask the expression of the other. The dominant allele is expressed in the phenotype, while the recessive allele is only expressed when two copies are present (homozygous recessive).
Explanation:
Mendel, an Austrian monk, conducted experiments on pea plants in the mid-1800s to study inheritance patterns. He meticulously crossed pea plants with different traits, such as flower color and seed shape, and analyzed the results over multiple generations. By observing the ratios of different traits in the offspring, he identified consistent patterns.
Mendel’s approach was different from earlier ideas of inheritance. Rather than believing traits were blended (a common belief at the time), he demonstrated that discrete units (now known as genes) controlled traits and were inherited in predictable ways. He used mathematical ratios to support his findings, such as the 3:1 ratio for dominant and recessive traits in the F2 generation, which led him to propose his laws.
His work laid the groundwork for the understanding of heredity, although the scientific community did not fully appreciate it until decades later, when the principles of genetics were confirmed through the study of chromosomes and DNA.