Escherichia coli is surprisingly tolerant to chromatinization by archaeal histones, suggesting that histones can become established as ubiquitous chromatin proteins without interfering critically with some key DNA-templated processes.

In Thermoplasma acidophilum, an archaeon without histones, a DNA-binding protein acquired from bacteria via horizontal gene transfer mediates histone-like chromatin architecture.

Archaeal histones compact DNA into nucleosome-like particles of varying sizes that contort sporadically and reorient DNA wrapping.

Similarities in the way that nucleosomes are organized into chromatin in archaea and eukaryotes suggest that chromatin might have been involved in gene regulation before its role in DNA packaging evolved.

The crenarchaeon Sulfolobus synthesizes the N-glycan core in the identical way as all Eukaryotes, which strengthens the hypothesis that the eukaryotic N-glycosylation is acquired from an ancient archaeon during eukaryogenesis.