Mendel’s laws of heredity refer to biological concepts of heredity first uncovered by the Austrian monk Gregor Mendel, who lived in the early 1800s. He conducted experiments crossing various sizes and colors of pea plants and recording the outcomes of these crosses revolutionized the understanding of heredity. Taken together, his laws make up the principles of Mendelian inheritance.
At the time of his experiments, Mendel knew nothing about genes or chromosomes. But through his work, he came to understand that garden peas transmit their visible traits (phenotypes) like color and height to their offspring in a measurable way. Also, Mendel found that through careful observation and record-keeping, he could predict the color and height of pea plants.
Key Points on Mendel’s Laws
- The law of inheritance was proposed by Gregor Mendel after conducting experiments on pea plants for seven years.
- Mendel’s laws of inheritance include the law of dominance, the law of segregation, and the law of independent assortment.
- The law of segregation states that every individual possesses two alleles and only one allele is passed on to the offspring.
- The law of independent assortment states that the inheritance of one pair of genes is independent of the inheritance of another pair.
The two experiments lead to the formulation of Mendel’s laws known as laws of inheritance which are:
- Law of Dominance: It is Mendel’s first law of inheritance. According to the law of dominance, hybrid offspring will only inherit the dominant trait in the phenotype. The alleles that are suppressed are called the recessive traits while the alleles that determine the trait are known as the dormant traits.
- Law of Segregation: The law of segregation states that during the production of gametes, two copies of each hereditary factor segregate so that offspring acquire one factor from each parent. In other words, allele pairs segregate during the formation of gamete and re-unite randomly during fertilization. This is also known as Mendel’s third law of inheritance.
- Law of Independent Assortment: It is the second law of inheritance, the law of independent assortment states that a pair of traits segregate independently of another pair during gamete formation. As the individual heredity factors assort independently, different traits get equal opportunity to occur together.