Sandwalk: Where did your chicken come from?

Wednesday, July 08, 2020

Where did your chicken come from?

Scientists have sequenced the genomes of modern domesticated chickens and compared them to the genomes of various wild pheasants in southern Asia. It has been known for some time that chickens resemble a species of pheasant called red jungle fowl and this led Charles Darwin to speculate that chickens were domesticated in India. Others have suggested Southeast Asia or China as the site of domestication.

The latest results show that modern chickens probably descend from a subspecies of red jungle fowl that inhabits the region around Myanmar (Wang et al., 2020). The subspecies is Gallus gallus spadiceus and the domesticated chicken subspecies is Gallus gallus domesticus. As you might expect, the two subspecies can interbreed.

The authors looked at a total of 863 genomes of domestic chickens, four species of jungle fowl, and all five subspecies of red jungle fowl. They identified a total of 33.4 million SNPs, which were enough to genetically distinguish between the various species AND the subspecies of red jungle fowl. (Contrary to popular belief, it is quite possible to assign a given genome to a subspecies (race) based entirely on genetic differences.)

The sequence data suggest that chickens were domesticated from wild G. g. spadiceus about 10,000 years ago in the northern part of Southeast Asia. The data also suggest that modern domesticated chickens (G. g. domesticus) from India, Pakistan, and Bangladesh interbred with another subspecies of red jungle fowl (G. g. murghi) after the original domestication. These chickens from South Asia contain substantial contributions from G. g. murghi ranging from 8-22%.

Next time you serve chicken, if someone asks you where it came from you won't be lying if you say it came from Myanmar.

Image credits: BBQ chicken, Creative Common License [Chicken BBQ]
Red Jungle Fowl, Creative Commons License [Red_Junglefowl_-Thailand]
Map: Lawler, A. (2020) Dawn of the chicken revealed in Southeast Asia, Science: 368: 1411.

Wang, M., Thakur, M., Peng, M. et al. (2020) 863 genomes reveal the origin and domestication of chicken. Cell Res (2020) [doi: 10.1038/s41422-020-0349-y]

2 comments :

Robert Byers said...: Subspecies(race) ? They are confused about what species much less subspecies. What stops the divisions or fixes them? What is a race?
Probably chickens come from those areas but creationists should question the dNA trails suggested. We should see options for populations to simply change bodyplans from influences working with the dna and then like results come about. so a option the DNA is just simply a replica but not a trail. For example the Giant panda and the Red panda both developed thier long bony thumb though they are not the same creature. So it could be they both have the same DNA score for the thumb.; Thursday, July 09, 2020 10:03:00 PM
Jonathan Badger said...: "(Contrary to popular belief, it is quite possible to assign a given genome to a subspecies (race) based entirely on genetic differences.)"

Like so many things this depends on definitions. Certainly it is possible to assign human ethnicity (which is where I suspect you are going with this) via genetic differences, but that is rather more specific than the idea of "race" that claims that all humans can be neatly categorized into three arbitrary categories.; Friday, July 10, 2020 1:35:00 AM

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The old argument of design in nature, as given by Paley, which formerly seemed to me to be so conclusive, fails, now that the law of natural selection has been discovered. We can no longer argue that, for instance, the beautiful hinge of a bivalve shell must have been made by an intelligent being, like the hinge of a door by man. There seems to be no more design in the variability of organic beings and in the action of natural selection, than in the course which the wind blows.Charles Darwin (c1880)

Although I am fully convinced of the truth of the views given in this volume, I by no means expect to convince experienced naturalists whose minds are stocked with a multitude of facts all viewed, during a long course of years, from a point of view directly opposite to mine. It is so easy to hide our ignorance under such expressions as "plan of creation," "unity of design," etc., and to think that we give an explanation when we only restate a fact. Any one whose disposition leads him to attach more weight to unexplained difficulties than to the explanation of a certain number of facts will certainly reject the theory.

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The world is not inhabited exclusively by fools, and when a subject arouses intense interest, as this one has, something other than semantics is usually at stake. Stephen Jay Gould (1982)
I have championed contingency, and will continue to do so, because its large realm and legitimate claims have been so poorly attended by evolutionary scientists who cannot discern the beat of this different drummer while their brains and ears remain tuned to only the sounds of general theory. Stephen Jay Gould (2002) p.1339
The essence of Darwinism lies in its claim that natural selection creates the fit. Variation is ubiquitous and random in direction. It supplies raw material only. Natural selection directs the course of evolutionary change. Stephen Jay Gould (1977)
Rudyard Kipling asked how the leopard got its spots, the rhino its wrinkled skin. He called his answers "just-so stories." When evolutionists try to explain form and behavior, they also tell just-so stories—and the agent is natural selection. Virtuosity in invention replaces testability as the criterion for acceptance. Stephen Jay Gould (1980)
Since 'change of gene frequencies in populations' is the 'official' definition of evolution, randomness has transgressed Darwin's border and asserted itself as an agent of evolutionary change. Stephen Jay Gould (1983) p.335
The first commandment for all versions of NOMA might be summarized by stating: "Thou shalt not mix the magisteria by claiming that God directly ordains important events in the history of nature by special interference knowable only through revelation and not accessible to science." In common parlance, we refer to such special interference as "miracle"—operationally defined as a unique and temporary suspension of natural law to reorder the facts of nature by divine fiat. Stephen Jay Gould (1999) p.84

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Wednesday, July 08, 2020

Where did your chicken come from?

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