Our results imply that the genomes of haplodiploid and of diploid higher
eukaryotes do not differ systematically in their recombination rates and associated parameters.
Unlike bacteria, some archaea also contain histones, but researchers weren't sure whether these microbes spool DNA around the protein bobbins the way
eukaryotes do.
We evolved from other eukaryotes, but
eukaryotes do not automatically evolve to be humans.
I would be surprised if such
eukaryotes did not date back to at least 3.0 billion years before the present.
Not exact matches
«It doesn't really matter which
eukaryote you look at, whether it's amoebas or plants or humans or fish or insects or anything,» says coauthor John Reeve, a microbiologist at Ohio State University.
The researchers saw that archaea DNA coils around the histones, similar to the way it
does in
eukaryotes.
The microbe's DNA, however,
does show a few telling similarities to those of
eukaryotes, says Woese, who worked with Bult to understand the new sequence.
Only later
did eukaryotes say good - bye to their strange relatives and set off on their own evolutionary path.
In particular, one of the enzymes needed for the synthesis of important glycoconjugates had not yet been identified: the apicomplexan organisms
do not have the GNA1 enzyme that fulfils this function in animals, plants and other
eukaryotes.
«How
do you make a
eukaryote, that's a big question,» said Schleper, a microbiologist at the University of Vienna in Austria.
Yeasts, like humans, are
eukaryotes: They have complex DNA packaged in chromosomes and riddled with introns (pieces of DNA that don't contribute to the final protein) and «junk DNA» with no known purpose.
These were the
eukaryotes — mainly plants and animals, whose cells had a nucleus — and the prokaryotes, such as bacteria, whose cells
did not.