Before mitosis, cell duplicates its DNA material so there are 46 chromosomes in duplicates and in total there are 46 x 2 = 92 sister chromatids. During mitosis, sister chromatids first join in the middle of the cell and then separate towards the opposite sides of the cell. After they separate, there are 46 sister chromatids on the one side and 46 sister chromatids on the other side. Each sister chromatid at the end of cytokinesis actually represents the chromosome of the newly formed daughter cell.
