Urkingdom | definition of Urkingdom by Medical dictionary
A conceptual ‘superkingdom’ lying at the root of the divergence between primitive organisms and bacteria from plants and animals, in which the mother organism, recently graduated from the primordial ooze, had a minimal complement of ‘ur’ genes essential for all organisms, including those genes encoding ribosomal RNA, ribosomal protein, enzymes and proteins required for DNA replication, DNA transcription and RNA translation
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References in periodicals archive
Ever since the proposal of using molecular markers such as 16S (or 18S) rRNA for comparing species similarity, in the late 1970s, followed by the outlining of a third "urkingdom
" (the Archaebacteria), our knowledge of organism relatedness has taken a great leap forward.
Remarkably, the archaic origin of this microbial urkingdom now does justice to its name.
Two of the three "aboriginal" lines of decent were initially conceptualized as "urkingdoms" of deep origin that were microbial and qualitatively different from eukaryotic organisms .