 The first model known as the " syntrophic model " proposes that a symbiotic relationship between the archaea and bacteria created the nucleus @-@ containing eukaryotic cell . ( Organisms of the Archaea and Bacteria domain have no cell nucleus . ) It is hypothesized that the symbiosis originated when ancient archaea , similar to modern methanogenic archaea , invaded and lived within bacteria similar to modern myxobacteria , eventually forming the early nucleus . This theory is analogous to the accepted theory for the origin of eukaryotic mitochondria and chloroplasts , which are thought to have developed from a similar endosymbiotic relationship between proto @-@ eukaryotes and aerobic bacteria . The archaeal origin of the nucleus is supported by observations that archaea and eukarya have similar genes for certain proteins , including histones . Observations that myxobacteria are motile , can form multicellular complexes , and possess kinases and G proteins similar to eukarya , support a bacterial origin for the eukaryotic cell . 
 The first model known as the " syntrophic model " <a href='uninflect' title='1'><mark>proposes</mark></a> that a symbiotic relationship between the archaea and bacteria created the nucleus @-@ containing eukaryotic cell . ( Organisms of the Archaea and Bacteria domain <a href='got' title='2'><mark>have</mark></a> no cell nucleus . ) It is hypothesized that the symbiosis originated when ancient archaea , similar to modern methanogenic archaea , invaded and lived within bacteria similar to modern myxobacteria , eventually forming the early nucleus . This theory <a href='drop_aux' title='3'><mark>is</mark></a>analogous to the accepted theory for the origin of eukaryotic mitochondria and chloroplasts , which are thought to <a href='been_done' title='4'><mark>have</mark></a> developed from a similar endosymbiotic relationship between proto @-@ eukaryotes and aerobic bacteria . The archaeal origin of the nucleus is supported by observations that archaea and eukarya <a href='got' title='5'><mark>have</mark></a> similar genes for certain proteins , including histones . Observations that myxobacteria are motile , can form multicellular complexes , and possess kinases and G proteins similar to eukarya , support a bacterial origin for the eukaryotic cell . 
The first model known as da " syntrophic model " propose dat a symbiotic relationship between the archaea and bacteria created tdanucleus @-@ containing eukaryotic cell . ( Organisms of thdarchaea and Bacteria domain got no cell nucleus . ) It is hypothesized tdatthedambiosis originated when ancient archaea , similar to modern methanogenic archaea , invaded and lived within bacteria similar to modern myxobacteria , eventually forming the daly nucleus . This theory analogous to the accepted theory fa the odain of eukaryotic mitochondria and chloroplasts , which r thought to done developed from a similar endosymbiotic relationship between proto @-@ eukaryotes and aerobic bacteria . The archaeal origin of the nucleus is supported by observations thdatrchaea and eukarya got similar genes for certain proteins , including histones . Observations that myxobacteria arrotile , can form multicellular complexes , and possess kinases and G proteins similar to eukarya , support a bacterial origin for the eukaryotic cell .