Assume that this is one of Santhi's chromosomes obtained from a sample of her blood. This chromosome is composed of two chromatids joined by a centromere. Which of the following statements is INCORRECT? The cell that contains these sister chromatids must be diploid. The sister chromatids were formed by replicating a single chromatid. The sister chromatids were joined by fertilization, bringing together a maternal and paternal chromatid.