DNA in the nucleus is packed into chromatin using proteins.Mitosis requires that the cell's chromatin be further packed into specific structures that are called chromosome which from a unique karyotype for each species.During mitosis the parent cell DNA is separated such that each daughter cell receives a complete karyotype.
细胞核中的DNA与蛋白质结合被包装成染色质。有丝分裂过程中细胞中的染色质进一步被包装成称为染色体的特定结构，这是每一个物种具有独特核型的原因。在有丝分裂过程中，母细胞DNA分离，从而每个子细胞获得一套完整的核型。