During mitosis a cell undergoes DNA and organelle duplication followed by a single division, each haploid daughter cell produced this way is genetically identical to the parent cell. In contrast to this meiotic cells still must duplicate their organelles, however the DNA is replicated and the cell fuses with another diploid cell, creating a tetraploid cell with 4 copies of each chromatid; and this is followed by two divisions. Firstly each homologous chromosome pair joins together and crossing over may occur, leading to genetic variation. The first division following the crossing over splits the homologous pairs apart, taking with it any exchanged genetic material. The second division splits apart chromosomes into individual chromatids into individual cells, where they are taken is influenced by their orientation, known as independent assortment. This leads to further genetic variation between the four newly formed, unique, daughter cells.