Patterson et al. (2012) recently published evidence for admixture in northern Europeans between a population resembling modern Sardinians (and the Neolithic Tyrolean Iceman, whose genome was published earlier this year), and, surprisingly Native Americans. The authors attribute the Amerindian-like ancestry element to a North Eurasian population that spawned Native Americans, and which also contributed ancestry to northern Europeans. They propose two possibilities for the origin of this admixture: (i) the Mesolithic Europeans resembled Amerindians, or (ii) there was an influx of Amerindian-like populations from the east during late prehistory. A palimpsest of these two processes may explain parts of the observed signal of admixture.
In a recent K=4
admixture experiment, I demonstrated that ADMIXTURE software produces an Amerindian ancestral component that closely tracks the signal of admixture using the D-statistic test. I have decided to make this test available for download and use with
DIYDodecad.
The test has four ancestral populations:
- European
- Asian
- African
- Amerindian
It is important to remember that some of these components track different aspects of ancestry that is better resolved at higher resolution. There are also populations that "don't fit well" in this 4-partite scheme (e.g., certain African or Australasian populations).
For example, the Amerindian component of this test may indicate (i) real recent Native American ancestry, (ii) East Eurasian ancestry found in Siberia and East Asia, (iii) the common signal of admixture differentiating most European groups from Sardinians and Near Eastern Caucasoid groups. Similarly, the Asian component may indicate Australasian, South Asian, or East Eurasian ancestry. And, the European component tracks the ancestry of individuals from West Eurasia in general, although it reaches is maximum in Sardinians.
This test may, however, be useful to Old World individuals who want to get an idea about the signal of admixture discovered by Patterson
et al.,
so I decided to make it available. For individuals who don't suspect recent Amerindian or Siberian/East Asian ancestry, and who don't belong to populations with recent such ancestry, the Amerindian component will most likely represent the aforementioned signal.
You need to extract the contents of the
RAR file to the working directory of
DIYDodecad. You use it by following exactly the instructions of the DIYDodecad README, but always type 'globe4' instead of 'dv3' in these instructions. You can consult the
spreadsheet for proportions of the 4 components in different world populations.
Terms of use: 'globe4', including all files in the downloaded RAR file is free for non-commercial personal use. Commercial uses are forbidden. Contact me for non-personal uses of the calculator.
