Which Mendelian principle describes how alleles separate into gametes?

• A. Principle of dominance
• B. Law of Segregation
• C. Law of Independent Assortment
• D. Law of Random Fertilization

Answer: (B)

Alleles separate into gametes during the formation of eggs and sperm. When an organism has two different alleles for a gene, those two copies separate so that each gamete receives only one allele. This happens in meiosis: homologous chromosomes carrying the different alleles segregate into different gametes, so offspring get one allele from each parent. This principle explains why a heterozygous individual can pass on either allele to the next generation and why traits follow predictable Mendelian patterns.

Other Mendelian ideas describe different ideas. Dominance explains how one allele can mask another in a heterozygote, not how alleles are separated into gametes. Independent assortment refers to how different genes can segregate independently of each other, not the separation of alleles for a single gene. Random fertilization describes the chance combination of gametes during mating, which adds variation but doesn’t explain the separation of alleles into separate gametes.