Last year, there was a paper in the Proceedings of the National Academy of Sciences that argued that a site in Chile had chicken bones within a prehistoric context. Basically, a research team compared DNA of chickens at El Arenal-1 in Chile to Mele Havea in Tonga (2000-1550 years old), and Fatu-ma-Futi in American Samoa, about the same date as El Arenal-1, and discovered they had similar structures. I reported that in this space, in conjunction with a paper on the prehistoric presence of sweet potatoes in Polynesia. The two together made for strong evidence of prehistoric trans-pacific contact of some sort.
Chickens feed at a poultry wholesale market in Chengdu of Sichuan Province, China.
Photo Credit: China Photos / Getty Images
However, recent DNA studies of the chicken bones from el Arenal-1 suggest that they are not in fact prehistoric, but rather have the same genetic structure as modern chickens from around the world. Apparently (I haven't read the paper), there is a definite DNA signature from pre-historic chickens, found on Easter Island, and that signature is missing in the collections studied from Chile, Tonga, and American Samoa.
The researchers call the modern chicken a "Kentucky Fried Chicken", arguing that modern-day chickens in restaurants and fast-food chains worldwide have essentially the same mtDNA, and that mtDNA is found in the so-called 'prehistoric chickens' in Chile (and in Tonga, and in American Samoa).
As for me, I don't understand how it is possible that a chicken bone direct-dated to the 14th century BC in Chile can have the same mtDNA as modern chickens. I was amazed at the Storey et al. paper last year, because Polynesian chickens in Chile seemed pretty unlikely, but I just don't see how these two pieces of data can both be true. This can't be the last word on this issue.
- TransPacific Connections, the story on Storey et al. 2007
- SEAARch: Chickens from Polynesia? Not so fast, thanks for the heads-up
- Chicken Bone Spurs Debate Over Americas' First Visitors, National Geographic
- Chicken And Chips Theory of Pacific Migration, TerraDaily
- Jaime Gongora et al. 2008. Indo-European and Asian origins for Chilean and Pacific chickens revealed by mtDNA. Proceedings of the National Academy of Sciences 105(30):10308-10313.
- Storey, Alice A. et al. 2007. Radiocarbon and DNA evidence for a pre-columbian introduction of Polynesian chickens to Chile". Proceedings of the National Academy of Sciences 104(25):10335-10339.
Comments
Does mitochondrial DNA always change through the years? I’m 52 and chickens look the same to me now as when we raised them when I was a child of 10. I know 40 years is an atom in the sea in comparison to the length of time we’re discussing. But a chicken is a rather, how do I say it, “generic” animal? Not saying there aren’t some amazing breeds out there!
Also, other than breed, and maybe injuries and defects, I can hardly tell one chicken from another. How different from each other is their DNA? Given a plain white generic egg-laying chicken in a commercial chicken house. (I’ve gathered eggs too… Yuck! I don’t recommend it.)
Am I being a chicken ‘bigot’?
That’s a really good question that I can’t answer! *How* alike are “Kentucky Fried Chickens” and how much wiggle room is there in the mtDNA. Maybe somebody who has actually read the paper can give us a clue.
Until then, bawk, bawk!
I dont really understand why you are commenting on a paper you havent read. If you read this new paper you would understand that it has major flaws in logic, and the authors have already had to admit some of their statements might not be right in the press. Stick with the Storey et al paper.
So, I’ve read both papers…..
The DNA used for these two studies is a particularly variable segment of mitochondrial DNA(mtDNA) – hard to know what the expected rate of change in this would be, but for a simple comparison the equivalent human mtDNA is estimated to change at about one position every 20 000 years or so (although that rate itself is highly controversial)- so no change over the time frame here – between the early Polynesian sites and the modern samples – is not very surprising. The point really with the Storey et al paper is that it demonstrates the chicken bone is from a pre-European South American archaeological context, and contains a sequence common in pre-European Polynesian chickens – so a good parsimonious argument is a Polynesian introduction. That the particular sequence (known as a haplotype) is widespread in modern chickens doesn’t affect Storey et al’s argument – just reflects the prehistorical and historical human-mediated movements of chickens worldwide.
I did read both papers.
So sequences of genes can often change relatively quickly, but the complete mtDNA would hardly have changed at all during the time period in discussion.
Thank you. That answered my question.
Thanks, Melanie! Your comment is exactly why I posted on something I hadn’t read–in the hope that someone else might have and could comment intelligently on it. I can’t read everything, and I had posted fairly substantially on Storey et al. Seemed like a reasonable compromise.
Kris
Read the book “1421″ how the Chinese sail around the world. The ships were huge. They carried everything would need on the voyages that last for years.
Chickens were a part of their preserves.
Yes, Asian chickens in S. America in the 1400s A.D. wouldn’t surprise me much. But the 14th century B.C.?
If it’s true, that’s veeeeery interesting!