What are sister chromatids?

Sister chromatids are indeed identical copies of a single chromosome that form after DNA replication during the S phase of the cell cycle. Each chromosome, once replicated, consists of two identical halves, known as sister chromatids, which are joined together at a region called the centromere. This structure is essential for accurate segregation during cell division, as it ensures that each daughter cell receives an identical set of chromosomes.

The identification of sister chromatids as identical copies highlights their role in ensuring genomic stability during the processes of mitosis and meiosis. Understanding this concept is fundamental to the study of genetics, cell biology, and the mechanisms underlying diseases such as cancer, where errors in chromosome segregation can lead to aneuploidy or other chromosomal abnormalities.