The simple repeat poly(dT-dG).poly(dC-dA) common to eukaryotes is absent from eubacteria and archaebacteria and rare in protozoans.

@article{Morris1986TheSR,
  title={The simple repeat poly(dT-dG).poly(dC-dA) common to eukaryotes is absent from eubacteria and archaebacteria and rare in protozoans.},
  author={James C Morris and Sidney R. Kushner and Robert Ivarie},
  journal={Molecular biology and evolution},
  year={1986},
  volume={3 4},
  pages={343-55}
}
Genomic DNA from a wide variety of prokaryotic and eukaryotic organisms has been assayed for the simple repeat sequence poly(dT-dG).poly(dC-dA) by Southern blotting and DNA slot blot hybridizations. Consistent with findings of others, we have found the simple alternating sequence to be present in multiple copies in all organisms in the animal kingdom (e.g., mammals, reptiles, amphibians, fish, crustaceans, insects, jellyfish, nematodes). The TG element was also found in lower eukaryotes… CONTINUE READING