Mendel formulated the law of of purity of gametes on the basis of

Options

A. monohybrid cross
B. dihybrid cross
C. test cross
D. back cross

Answer

**Step-by-Step Solution:**

1. **Understanding Mendel's Law of Purity of Gametes**: Mendel's law of purity of gametes states that during the formation of gametes, the alleles for a trait segregate so that each gamete carries only one allele for each trait. This means that gametes are pure in terms of the genetic information they carry.

2. **Monohybrid Cross**: Mendel conducted experiments using monohybrid crosses, which involve the inheritance of a single contrasting trait. For example, he studied the trait of height in pea plants, where one allele represented tallness (T) and the other represented dwarfism (t).

3. **Setting Up the Cross**: In a typical monohybrid cross, Mendel would cross a pure tall plant (TT) with a pure dwarf plant (tt). The gametes produced by the tall plant would be T (dominant), and the gametes produced by the dwarf plant would be t (recessive).

4. **F1 Generation**: The offspring (F1 generation) from this cross would all be heterozygous (Tt), displaying the dominant trait (tall). This shows that the dominant allele masks the presence of the recessive allele.

5. **Self-Fertilization of F1 Generation**: When Mendel allowed the F1 plants (Tt) to self-fertilize, he observed the next generation (F2). The possible combinations of alleles from the F1 generation would be TT, Tt, Tt, and tt.

6. **F2 Generation Ratio**: The phenotypic ratio in the F2 generation was found to be 3 tall (TT and Tt) to 1 dwarf (tt). This ratio illustrates the segregation of alleles during gamete formation.

7. **Conclusion**: The results of the monohybrid cross demonstrated that the traits do not blend but remain distinct and separate in the gametes. This led Mendel to formulate the law of purity of gametes, confirming that each gamete carries only one allele for each trait.

**Final Answer**: Mendel formulated the law of purity of gametes based on the results of the monohybrid cross.

---