Homologous chromosomes are defined by which characteristics?

• A. Homologous Chromosomes
• B. Non-homologous pairs
• C. Sister chromatids
• D. Chromosome replicas

Answer: (A)

The defining feature of homologous chromosomes is that they are a matched pair in a diploid cell: the two chromosomes carry the same genes in the same order and usually are similar in length and centromere position, one inherited from each parent. They may carry different alleles for those genes, but their gene content and arrangement align so they can pair during meiosis and segregate properly. This is why they are considered homologous to each other, unlike the other choices. Non-homologous pairs do not share the same gene loci, so they aren’t homologous. Sister chromatids are identical copies of the same chromosome after DNA replication, not a different chromosome from the parent, and chromosome replicas refer to duplicated chromosomes, again not the paired, parental-origin counterpart that defines homologous chromosomes.