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Science Answers Question: Where Did Blue Eggs Come From?

Viruses can cause foodborne illnesses, but viruses can also shape the evolution and diversity of a species to create something entirely new on the menu.

Take the much-in-demand blue eggs that trend-setting foodies say are tastier and better for baking than brown eggs. In its latest issue, the Public Library of Science journal PLOS ONE has created a worldwide stir by publishing a University of Nottingham study that says blue eggs originated from a genetic mutation.

In findings that are parallel to research conducted by Chinese scientists on Asian and American breeds, the School of Biology at Nottingham found that the first blue eggs were produced by the South American chicken known as the Mapuche fowl and their European descendants, the Araucana, between 200 and 500 years ago.

The four-year Nottingham study is expected to help with agricultural breeding techniques that will be needed to meet the growing demand for blue eggs.

The study took advantage of unique genetic resources from “heritage” (fancy poultry) breeders to identify the exact location at fine resolution of the mutation in the genome in blue egg-laying chickens. Further genetic study found the cause of the blue-colored eggshell was an ancient and harmless retrovirus in the domestic chicken.

A retrovirus is simply a virus that carries the genetic blueprint in the form of ribonucleic acid (RNA). It reproduces itself in the host cell using an enzyme that turns the RNA into deoxyribonucleic acid or DNA. That’s how the genetic material from the retrovirus becomes part of the DNA of the infected cell.

Blue eggs came about because the effect of the retrovirus was to leave an accumulation of green-blue bile pigment in the eggshell as it develops in the hen.

“An unexpected find was the unique integration sites for the retroviruses in South American/European and Asian chickens,” said David Wragg, who led the Nottingham research project. “It shows the importance of viruses in shaping evolution and diversity of species.”

“It’s quite remarkable – retroviruses are generally considered to integrate at random locations in the genome, and so the chance of retroviruses integrating at more or less the same location in two chicken populations is extremely low,” Wragg added.

He says chicken owners hundreds of years ago must have noticed that trait and incorporated it into their subsequent breeding.

While common to other bird species such as Robins, the researchers say only the rare native breeds of chickens produce them. The challenge for agriculture now, they say, will be to conserve and promote them.

© Food Safety News
  • Tessa

    OMG!! And it’s viruses they use to make GMO foods too! I will never eat another blue or brown egg ever again. We MUST demand labels on all eggs clearly stating if the eggs came from a bird with virus. All this genetic mutation is unsustainable and it is destroying us all. I am so upset about this mutant stuff.

    • LMG

      Tessa – You are very misinformed about “this mutant stuff”. Viruses insert their genetic information into host cells to reproduce. On their own viruses do not have everything they need to reproduce so they need a host cell. This has been happening in nature from the beginning. In fact about 8% of the human genetic code is from viral genetic code. So for these blue egg laying chickens this virus was using their cells long ago. The genetic code left behind in the chickens makes them have blue pigment in the shells but they are not currently spreading whatever virus this was from their genetic history. The following is a good explanation of how viruses work. http://science.howstuffworks.com/life/cellular-microscopic/virus-human1.htm But basically to avoid any foods containing any viral genetic information would mean you wouldn’t be eating anything.
      Sincerely,
      Concerned Food Microbiologist.

  • Ann

    Tessa, this is a natural process, not a man-made artificial one as GMO organisms are. Genetic mutations happen naturally all the time in all living beings, and have been doing so since life began on this planet. Your body (and everyone else’s) has hundreds if not thousands of viruses and bacteria in it. Study science and you’ll understand.

  • J T

    I think Tessa’s hereditary line may have missed a few of those evolutionary mutations that the rest of us have benefited from…

  • Michael Bulger

    “… unique genetic resources from “heritage” (fancy poultry) breeders…”

    I don’t understand why News Desk dealt with heritage poultry in this manner. It seems to belittle the term heritage and suggest that it is an arbitrary or whimsical fantasy not worthy of serious explanation.

    In fact, the term has a definition (see American Livestock Breeds Conservancy http://www.albc-usa.org/heritagechicken/definition.html). We could go on and on about the importance of biological diversity or preserving breeds, but I just thought I’d point out that News Desk injected a bit of unnecessary emotion/opinion where they could have just as easily offered readers an informative tidbit of real knowledge.

  • Matthew

    I believe Tessa was being sarcastic and her point was that it’s just as silly to be afraid of GMO’s as it is to be afraid of eating anything.

    • Organic Foodie

      Matthew, you obviously have not been doing your research on GMOs . I would strongly urge you to dig deeper than what the media is paid to feed you….

  • JoeDrager

    We’re all gonna die. Personally, I expect to do it at about 106 years of age.