the evolutionary history within excavates is Kipferlia bialata. According to recent research this organism is able to replicate without some key proteins for replicating DNA (see below). DNA replication, chromosome segregation, and sex A recent study using comparative genomics has revealed extensive loss of the DNA replication and segregation protein complements within Metamonada and has highlighted that the genomes of C. membranifera and C. frisia are even further reduced. These genomes lack the DNA replication proteins of the origin recognition complex (ORC), Cdc6, some components of the GINS complex and some subunits of polymerases delta and epsilon, as well as most structural kinetochore subunits, a microtubule plus-end tracking complex and all subunits of the Ndc80 complex involved in chromosome segregation. ORC and Cdc6 are proteins in charge of replication initiation and licensing in eukaryotes, and their absence appears to indicate the existence of a non-standard and as-yet undescribed mechanism to start replication. The absence of Ndc80 complex proteins also suggest that a non-standard mechanism could be in place for chromosome attachment to microtubules for chromosome segregation. Carpediemonas is the first known eukaryote to possess such drastically altered DNA replication and segregation machineries. Since Carpediemonas reproduces, it is obvious that they do replicate their DNA and researchers have proposed a hypothesis on how replication starts. This hypothesis uses elements of processes observed in other species but takes into account the specific protein complements found in Carpediemonas. In short: replication is proposed to proceed by a Dmc1-dependent homologous recombination mechanism that does not require origins of replication and that is mediated by RNA:DNA hybrids. This hypothesis still needs to be experimentally proven. Sexual or parasexual reproduction have not been directly observed in Metamonada. However, the study confirms the conservation of key meiotic proteins in the group with the bonus finding that Carpediemonas species have homologs from the tmcB family and sperm-specific channel subunits, the latter only reported previously only in Opisthokonta and three other protists. The presence of such proteins means that further investigations are required to understand if sex occurs, and if these proteins actually participate during sex and what their role could be. In short, Carpediemonas are intriguing microbial eukaryotes. References Metamonads Excavata genera Monotypic eukaryote genera