Question

What is the law of segregation?

Answer 1

Mendel's laws:

1. Gregor Mendel performed several experiments with pea plants. His observations are the foundation for modern genetics, and important for heredity study.
2. They help in determining the inheritance pattern of a trait implemented in hybridization experiments for better characteristics.
3. Mendel proposed three laws of inheritance: the law of segregation, the law of dominance, and law of independent assortment.

Law of segregation :

1. The law of segregation states that the two alleles of a pair segregate or separate during gamete formation or meiosis cell division such that only one allele will be present in each gamete.
2. The law of segregation can be deduced from monohybrid cross where a cross is performed between a pure tall pea plant and dwarf pea plant.
3. The plants of F, generation are all hybrid tall (Tt) though they have received the factor (gene) for dwarfness.
4. If the hybrids are allowed to self pollinate then the plants of second filial or F, generation, appear to have both tall and dwarf in the phenotypic ratio of 3: 1.
5. Further self breeding of these F, plants, shows that the dwarf plants breeds true and produce only dwarf plant (tt). Amongst tall plants 1/3 breed true i.e., produce only tall plants (TT), the remaining 2/3 of the F, tall plants behave as hybrids (Tt) and produce both tall and dwarf 1:1 in the ratio of 3:1.
6. Therefore the F, phenotypic ratio of 3:1 is genotypically, 1:2:1, i.e., 1 pure tall (TT): hybrid tall (Tt): 1 dwarf (tt).
7. This law is based on his four basic concepts:
   
   1. Genes exist in multiple allelic forms.
   2. When gametes are produced by meiosis, the allele pairs separate, leaving a single allele in each gamete.
   3. Each organism inherits two alleles of her for each trait.
   4. The two alleles of the pair are different. One is dominant and the other is recessive.