In genetics, what does the law of segregation state?

• A. Recombination of alleles occurs randomly during fertilization.
• B. Traits are determined by a single gene only.
• C. Alleles segregate during gamete formation; offspring receive one allele from each parent
• D. Dominant alleles always determine phenotype in offspring.

Answer: (C)

The main idea is that each individual carries two copies of a gene, one from each parent, and these copies separate when gametes are formed. During meiosis, the two alleles for a gene segregate into different gametes, so any given gamete has only one allele. When fertilization occurs, the zygote receives one allele from each parent, restoring the pair. This is why a heterozygous parent (having two different alleles) produces gametes with either allele, and why offspring genotypes follow predictable ratios (for example, a cross between two heterozygotes yields a mix of homozygous and heterozygous offspring). It’s not about recombination at fertilization, it doesn’t claim traits are governed by a single gene, and it doesn’t state that dominant alleles always determine phenotype—the law specifically describes how alleles are distributed into gametes and re-paired in offspring.