What best describes homologous chromosomes?

• A. Sister chromatids
• B. The two chromosomes that carry identical genes in the same order from the two parents
• C. Non-homologous chromosomes
• D. Chromosome pairs that do not pair during meiosis

Answer: (B)

Homologous chromosomes are a matched pair, with one chromosome from each parent, that carry the same genes in the same order. They may have different alleles for those genes, which is why siblings can show different traits, yet the gene order is preserved so they line up during meiosis and can exchange genetic material. This pairing and potential recombination is what characterizes them as homologous. Sister chromatids, on the other hand, are identical copies of a single chromosome that have been replicated and remain attached until separation, not a maternal and paternal pair. Non-homologous chromosomes are different chromosomes that do not share the same gene order, so they do not pair with each other during meiosis. And chromosome pairs that do not pair during meiosis miss the crucial pairing of homologous chromosomes, which is a hallmark of meiosis.