It's the classic conundrum: What came first, the chicken or the egg? When it comes to the simple answer to the question as it relates to Gallus gallus domesticus (a.k.a. the chicken), that riddle's been largely solved thanks to evolution. At some point thousands of years ago, ancient chicken breeders chose two tame jungle fowl (gallus gallus) and the resulting union produced the egg of the world's first genetically distinct chicken. In summary: egg predates chicken.

However, a new study from the University of Geneva suggests that the egg's temporal superiority may be even more profound than this simple brain teaser suggests. In 2017, scientists discovered the single-celled Ichthyosporean microbe Chromosphaera perkinsii in marine sediments near Hawaii. Although new to human science, this organism was a serious old-timer, having separated from the animal evolutionary line more than a billion years ago -- long before the first appearance of animals. However, scientists from Switzerland and the U.S. have discovered that this animal contained genetic instructions from embryonic development, meaning that the eggs existed even before life itself. The results of the study were published earlier this year in the journal Nature.

"This paper gets at the core question of developmental biology, which is how we go from one cell to a whole animal, by looking at a related process in a weird, microbial relative to animals," John Burns, a senior research scientist at Bigelow Laboratory in Maine said in a press statement. "We're using our emerging understanding of the diversity of microbial life to answer questions about how we got here and how life works in other evolutionary branches."

We know that single-celled organisms were the first forms of life on Earth, but piecing together the complete roadmap between yeast and, say, blue whales hasn't been easy. In their quest to understand how microbial life developed into proto-animals, researchers spotted this incredible embryonic by closely observing ancient protist C. perkinsii. The team -- lead by Omaya Dudin form the University of Geneva -- found that these cells reached their maximum size and separated with growing any further. To do this, they formed "multicellular colonies" that, incredibly, resembled embryonic development. Burns analyzed the genetic activity in these "colonies" and compared them to the process of mitosis found in other animal species.

"Some of the genes that the microbe uses to drive its development, and the general patterns they follow, are similar to what we observe in animals," Burns said in a press statement. "These ancient relatives of animals may contain some programs that their direct animal ancestors built on through evolution."

While similar biological processes often point to a related genetic lineage, there always lurks the possibility that this embryonic similarity developed through convergent evolution -- when nature develops the same effective processes multiple times independent of each other. This is the same idea that drives the convergent evolutionary quirk known as carcinization where nature keeps trying to turn animals into crabs.

But whether chicken, crab, human, or blue whale, science continues to support that the egg -- or at least some impressive co-production of it -- predates us all.