Before the DNA is replicated in a human somatic cell, the cell has 46 chromosomes. Also, after the sister chromatids are separated during Anaphase, the chromosome number in the cell doubles to 72, so when the sister chromatids are joined, Why isn't the chromosome number also 72? On the internet, some sources say that one chromosome in a cell that hasn't replicated its DNA is equal to one chromatid. Is this correct, or are chromosomes and chromatids structurally different?