The law of segregation is also known as
Mendel's first law describes allele pairs remaining discrete within a heterozygote and segregating unchanged into gametes during meiosis without blending or contamination. Each gamete receives a single allele in pure form, which explains historic name purity of gametes. For genotype Aa, meiosis produces 50% A and 50% a gametes with equal probability. Random fertilization restores diploidy, yielding classic 3:1 F2 phenotypic ratio where recessive trait reappears intact after being masked in F1. This principle underpins monohybrid inheritance and gamete purity concept.
Ref: Griffiths et al., Introduction to Genetic Analysis, 12th ed., Chapter 2: Law of Segregation and Purity of Gametes
