Which statement best describes Mendel's law of independent assortment?

Which statement best describes Mendel's law of independent assortment?

• A. Alleles assort independently if all possible gametes are formed in equal portions.
• B. Genes always assort independently.
• C. Crossing over occurs during meiosis.
• D. Mendel's law states that linkage occurs only for genes on different chromosomes.

Answer: (A)

Independent assortment means alleles of different genes segregate into gametes independently, so all possible allele combinations appear in the offspring with equal frequency when the genes are unlinked. This leads to the familiar outcome that, for a dihybrid cross, all gamete types occur in equal proportions, such as AB, Ab, aB, and ab, provided there is no linkage and no selection. The statement that best describes this is that alleles assort independently if all possible gametes are formed in equal portions, which captures both the independence of assortment and the equal-frequency result. The other statements mix in mechanisms or incorrect generalizations: crossing over is a meiotic process that can create new combinations but isn’t the law itself; linkage describes genes on the same chromosome and reduces independent assortment; and the law is not about genes always assorting independently under all circumstances.

Independent assortment means alleles of different genes segregate into gametes independently, so all possible allele combinations appear in the offspring with equal frequency when the genes are unlinked. This leads to the familiar outcome that, for a dihybrid cross, all gamete types occur in equal proportions, such as AB, Ab, aB, and ab, provided there is no linkage and no selection. The statement that best describes this is that alleles assort independently if all possible gametes are formed in equal portions, which captures both the independence of assortment and the equal-frequency result. The other statements mix in mechanisms or incorrect generalizations: crossing over is a meiotic process that can create new combinations but isn’t the law itself; linkage describes genes on the same chromosome and reduces independent assortment; and the law is not about genes always assorting independently under all circumstances.