Linda Besner updates the age-old debate about the chicken and the egg, as scientists have recently claimed to have solved the problem:
The one hailing Team Chicken revolves around a British paper called “Structural Control of Crystal Nuclei by Eggshell Protein,” written by Colin Freeman and John Harding from the University of Sheffield and David Quigley and P. Mark Rodger from the University of Warwick. They used a supercomputer to figure out how eggshells are formed, and it turns out they depend upon a protein found in chicken ovaries called ovocledidin-17. This would mean that an egg can only come into being if formed inside a chicken.
Team Egg’s argument involves less computer modelling and more taxonomy. The question, the Eggers say, hinges on how you define a chicken egg—is it an egg laid by a chicken or an egg from which a chicken emerges? Today’s barnyard Gallus gallus domesticus must have evolved from an earlier thingummy with chicken-like qualities. In 2008, Jonas Eriksson et al. argued that the chicken is a hybrid, the offspring of both the red and the grey junglefowl. At some point (here I’m fudging, because evolution takes longer than this, but you get the idea) something that wasn’t quite a chicken laid an egg, from which something hatched, which tipped over into chickendom. The zygote in which the genetic change happened that created the first chicken was contained inside an egg. So—the egg came first.
Besner sides with Team Egg:
The egg is all surprise, a sphere of unexercised influence, an occlusion. It’s what you have before you know what you have. … If there is a feathered state beyond this, I’m not expecting to get there in this lifetime. I’m not sure I want to; the egg is where the mystery is.
Above video via Kottke:
As the curator of the egg collection at London’s Natural History Museum explains, the double egg is rare but real and results from a fully formed egg being pushed back into the ovary, where another egg forms around it.