All ciliate possess multiple dimorphic nuclei which have separated the functions of protein synthesis, performed by the macronuclei or somatic-nuclei, and heritable DNA replication, performed by the micronuclei or germ-line nuclei. The class Karyorelictea are characterised by an inability to replicate the macronucleus, a process called amitosis, which must be re-synthesized from the micronucleus every cell division. The majority are unculturable, although clonal lines of Loxodes have been developed. The class is divided into three orders, Protostomatida, Loxodida and Protoheterotrichida, which were defined morphologically, but have been confirmed with molecular phylogenetics.