A pea plant which is homozygous for green pods which are inflated [GGII] is crossed with a homozygous plant for yellow pods which are constricted [ggii]. Answer the following questions:
State Mendel’s law of ‘Segregation of Gametes’.
Topic: Law of Segregation
Answer
MENDEL’S LAW OF SEGREGATION states that the two members of a pair of factors (alleles) SEPARATE from each other during the formation of gametes, so that each gamete receives only ONE allele of the pair. The alleles remain unaltered and are restored in pairs at fertilisation.
The essential words are that the alleles SEPARATE during GAMETE FORMATION and each gamete receives only ONE.
It is also called the LAW OF PURITY OF GAMETES, and that name is worth giving: a gamete is "pure" because it carries one allele only, never a blend of the two.
THE EVIDENCE for it is the reappearance of the recessive character in F2. If the alleles had blended in the F1 hybrid, the recessive character would have been lost for ever. That it returns unchanged proves they separated intact.
THE PHYSICAL BASIS, worth adding: the alleles separate because the HOMOLOGOUS CHROMOSOMES carrying them separate during MEIOSIS.