How would the DNA in two sister chromatids compare to each other?

Sister chromatids are formed during DNA replication in the S phase of the cell cycle. When a chromosome duplicates, each half is a sister chromatid, and they contain the exact same sequence of nucleotides. This means that the DNA in sister chromatids is entirely identical to each other, reflecting an exact copy of the original chromosome prior to replication.

This uniformity is crucial for accurate cell division, as it ensures that each daughter cell receives an identical set of genetic information. Any alteration or mutation does not occur between sister chromatids until after they have separated during cell division, ensuring genetic consistency during this critical process. Thus, the DNA in the two sister chromatids would indeed be identical.