July 26, 2012

Ancient DNA... of chickens

Sure, why not?

Alice A. Storey, Investigating the Global Dispersal of Chickens in Prehistory Using Ancient Mitochondrial DNA Signatures. PLoS ONE, 2012. Open access ··> LINK [DOI: 10.1371/journal.pone.0039171]

The authors managed to produce more or less reliable mtDNA haplotypes for 48 remains of historical and prehistorical chickens from Thailand, Pacific Islands, Latin America (a pre-Columbian site in Chile but post-Columbian sites elsewhere) and (medieval) Spain.

Excepting the oldest Thai haplotype, all them belonged to haplogroups D and E, as follows:

Fig. 1
In spite of the authors burying most of the relevant data in the supplemental material, I was able to conclude that the ancient haplotypes (ah) above mean in terms of samples:

  • Haplogroup E:
    • cluster 1:
      • ah1 Pacific Is. (n=1)
      • ah2 Pacific Is. (n=4), Thailand (n=1), Chile (n=1)
      • ah6 Peru (n=1)
    • cluster 2:
      • ah3 Pacific Is. (n=10), Chile (n=2), Spain (n=3), Haiti (n=1), Florida (n=1)
      • ah4 Spain (n=1)
      • ah5 Bolivia (n=3)
      • ah7 Spain (n=1)
  • Haplogroup D:
      • ah9 Pacific Is. (n=1), Peru (n=1)
    • cluster 3:
      • ah10 Pacific Is. (n=14)
      • ah11 Pacific Is. (n=1)
  • Haplogroup B (not shown):
      • ah12 Thailand (n=1)
There is no ah8 apparently. 

It must be noted that the ah9 haplotype from Peru is very early post-Columbian, from before 1600 CE, making it another likely evidence of Polynesian introduction of chicken in South America, along with the Chilean sites (which allow for no other explanation). However the Peruvian haplotype is more related to Micronesia than to Hawaii or Rapa Nui.

Other 17th century samples from Bolivia and Peru (ah5 and ah6) have no obvious connection with either plausible origin. Instead Caribbean sites are probably related to Spain.

A simplified geographical distribution is also offered (oddly enough on a pre-WWI map):

Fig. 2

The authors conclude:

As a result of the careful analysis of archaeologically associated, and in some cases directly dated, ancient DNA samples an early global distribution of haplogroup E chickens has been revealed. This dispersal out of Asia began before 3000 years ago and involved the movement of chickens both westwards to Europe and eastwards into the Pacific. The distribution of haplogroup D likely represents a separate dispersal into the Pacific from a distinct Asian domestication centre. The eventual identification of these centers will greatly enrich our understanding of chicken domestication and the history of dispersals from multiple locations. While unambiguous data does not yet exist to trace any of the detected mtDNA signatures back to specific domestication centers, the analysis of ancient DNA sequences presented here is an important first step towards it. Future research needs to focus on markers identified, from both full mtDNA genomes and nuclear genes which are subsequently targeted in ancient specimens, examined within their historical and/or archaeological context.

2 comments:

  1. "Sure, why not?"

    Because any information about any species usually has wider implications.

    "It must be noted that the ah9 haplotype from Peru is very early post-Columbian, from before 1600 CE, making it another likely evidence of Polynesian introduction of chicken in South America, along with the Chilean sites (which allow for no other explanation)".

    There was a program on the radio recently where a New Zealand Anthropologist mentioned the 'chicken' evidence as yet more evidence for Polynesian arrival in the Americas. Thanks for the link. Her name is Lisa Matisoo-Smith if you wish to follow it up. Here's a short interview with her that is perhaps mildly interesting:

    http://www.youtube.com/watch?v=KACEB8l_Knw

    "(oddly enough on a pre-WWI map)"

    You think Spain's the only place with economic problems? The map is probably from the University of Otago. Universities in New Zealand are remarkably underfunded.

    ReplyDelete
    Replies
    1. It's a wrongly chosen Wikipedia map.

      We already knew about the likelihood of Polynesian arrival to America based, effectively, on chicken genetics. At least I did.

      Delete

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