Evolution: DNA storage in Archaea and eukaryotes differs (Evolution)

by David Turell , Saturday, May 01, 2021, 16:17 (1300 days ago) @ David Turell

The new study:

https://science.sciencemag.org/content/372/6541/477.2?utm_campaign=ec_sci_2021-04-29&am...

"Only eukaryotes and archaea use histones to package their DNA. This observation has prompted suggestions of an evolutionary affinity between these two domains of life. However, there are many differences between the structure of histones between the domains. Bowerman et al. extended earlier work to show how archaeal histones store and unpack DNA. In eukaryotes, a packet of four pairs of histones wraps around every ∼147 base pairs of DNA in a structure called a nucleosome. By contrast, the archaeal equivalent of a nucleosome, the archaeasome, forms a histone core with more than four histone pairs. Archaeasomes can expand, in effect stretching the coil, to open up the DNA in a way that is very different from how this process occurs in eukaryotes."

Comment: the theory that similar DNA storage means we descended from Archaea is not supported by this study. The storage methods are very different, but somewhat similar in that we both use histones.