Here in the U.S., our eggs mostly come in two colors: white and brown. But there are two breeds, one in Chile and one in China, that are known to lay blue eggs. Yeah, weird, right? And a new study has figured out why that happens.
The Araucana chicken from Chile and the Dongxiang and Lushi chickens from China (none of which are particularly common in North America) are known to lay pale-blue eggs. This is rare for a chicken; while bird eggs can come in all sorts of colors and patterns, chicken eggs are almost always white or brown. So what's the deal?
A new study found that a single gene, called callee oocyan, is responsible for the odd coloration of these blue chicken eggs. But how did it get there? Turns out that these chickens have a high incidence of a particular retrovirus, called EAV-HP. Retroviruses are a type of virus that integrates its own genetic data into the host in an unusual order. Instead of transcribing DNA into RNA and then into protein, retroviruses operate backwards, retroviruses have RNA, which they use to make DNA, and then integrate that DNA into the DNA of their hosts. HIV is probably the best-known retrovirus.
This EAV-HP retrovirus is responsible for inserting that weird gene, the one that turns the chicken eggs blue. Specifically, it changes the chemistry of the eggshell so that it can take in biliverdin, a bile pigment, from the chicken's uterus. Weird! And not necessarily harmful; blue eggs are widely eaten and the Araucana, in particular, is a very popular exotic chicken breed. But now you know why their eggs are blue!
[via Virology Blog]
I'm not sure I go for this. There are many araucanas, or more properly americanas, in backyard flocks. If this is a virus acquired trait, why hasn't it been passed to other chicken breeds? A chicken is a chicken after all...
The virus itself may not be there anymore - but the changed genes simply have been passed down from bird to bird - essentially creating a new breed.
Most peopel wouldnt believe how much humans have been mutated and changed by viral dna over 100-s of thousands of years.
What are they talking about?? Fenton Blue chickens originally from England Lay blue eggs. Humans have never mutated. All bones found have EXACTLY the same as we have...
IT doesnt have to be bones, rather minor alterations picked up over long periodes of time.
"About eight percent of human genetic material comes from a virus and not from our ancestors, according to researchers in Japan and the U.S."