title: Possible translocation of a gene for thymidylate kinase from the chloroplast to the nuclear genome during evolution.
abstract: On the basis of the fact that in Acetabularia three out of four enzymes that are involved in deoxyribonucleotide metabolism are translated on 70 S ribosomes, while a fourth one is synthesized on 80 S ribosomes, the suggestion was made that translation on 80 S ribosomes might reflect an evolutionarily more recent situation while translation on 70 S ribosomes might be of more ancient origin. This hypothesis prompted experiments aimed at defining the site of translation of thymidylate kinase in a species closely related to Acetabularia but long ago separated from it: Batophora oerstedii. It was demonstrated that in this species, in contrast to a number of Acetabulariae, thymidylate kinase is translated on 70 S ribosomes. A possible, appealing interpretation of this finding is that during evolution the coding site for thymidylate kinase has been translocated from the chloroplast to the nuclear genome.
mesh_terms: D000076:Acetabularia / Q000235:genetics; D005075:Biological Evolution; D000460:Chlorophyta / Q000201:enzymology / Q000235:genetics; D002736:Chloroplasts; D005796:Genes; D009703:Nucleoside-Phosphate Kinase / Q000235:genetics*; D010770:Phosphotransferases / Q000235:genetics*; D012270:Ribosomes; D014178:Translocation, Genetic
chemical_list: D010770:Phosphotransferases; D009703:Nucleoside-Phosphate Kinase; C020093:dTMP kinase