Scientists have for the first time synthesized a chromosome of a eukaryotic cell (in this case, a yeast). A genetic sequence was designed on a computer, then pieced together and integrated into a living yeast cell to create a semi-artificial life-form.
Life is classified as either eukaryotic or prokaryotic. Prokaryotes evolved first, and lack the membrane-bound organelles (i.e., the nucleus), which are a feature of eukaryotes.