My Biogeographical Ancestry

There are several different ways to figure out your genetic ancestry. One way that 23andme shows your ancestry is by comparison with reference populations of the HGDP (Human Genome Diversity Project) dataset. I have listed how similar I am to various groups in the table below:

Reference Population Similarity Groups Included
Central & South Asians 67.14 Pathan, Makrani, Kalash, Hazara, Balochi, Sindhi, Brahui and Burusho
Northern Europeans 66.94 western Russia, France, Orkney Islands
Southern Europeans 66.93 northern Italy, Tuscany, Sardinia, French Basque
Near Easterners 66.82 Palestinian, Druze, Bedouin
Siberians 66.55 Yakut
Eastern Asians 66.48 Japan, Cambodia, China (Dai, Daur, Han, Hezhen, Lahu, Miaozu, Mongola, Naxi, Oroqen, She, Tu, Tujia, Uygu, Xibo, Yizu)
North Americans 66.47 Pima, Maya
South Americans 66.43 Surui, Karitiana, Piapoco, Curripaco
Oceanians 66.38 Papuans, Melanesians
Northern Africans 66.16 Mozabite
Eastern Africans 64.13 Kenya
Southern Africans 64.04 San, Bantu speaking South Africans
Central Africans 64.01 Biaka, Mbuti Pygmies
Western Africans 63.98 Mandenka, Yoruba

My numbers are not too different from anyone from the northwestern part of the South Asian subcontinent.

One thing to consider over here is that you are being compared to a specific set of populations. As you can see, there is no Indian references here. Similarly, Near Easterners are represented only by samples from Israel and North Africans by one Algerian population. I wonder what the case would be if they had Egyptians or Ethiopians etc in their reference.

Another way to look at your genetic ancestry is with a PCA (Principal Component Analysis) plot. With the same reference populations mentioned above, 23andme calculated the two dimensions of largest variation among that data. These two axes don’t completely describe the variation across the samples, but being the two largest components they can be used to project your genetic data in that space. At the world level, I am the green marker in the middle of the Central/South Asian cluster.

In the South Asian PCA plot, I am in the middle of the Pathan cluster and right at the top edge of the Sindhi one.

Now this doesn’t make me a Pathan. For one thing, 23andme’s reference populations do not have any Punjabis. I am sharing with a number of North Indians and Pakistanis, including several Punjabis, and they all lie around me in the plot.

There is another problem with a PCA plot though. We are looking at the two most significant dimensions, but there are other dimensions too and they combined together could account for a lot of the variation among people’s genomes. Also, let’s say we have someone who is a child of a European and an East Asian parent. Now that person, who is 50% East Asian and 50% European, would be placed about midway between the East Asian and European clusters. That’s where the Uygur and Hazara clusters are. So we can’t say that someone is Uygur just because they are placed in the Uygur cluster in a PCA plot.

There are other ways to look at your genetic ancestry and I have been exploring a bunch of them. We’ll talk about them next.

Author: Zack

Dad, gadget guy, bookworm, political animal, global nomad, cyclist, hiker, tennis player, photographer

4 thoughts on “My Biogeographical Ancestry”

  1. hat’s where the Uygur and Hazara clusters are. So we can’t say that someone is Uygur just because they are placed in the Uygur cluster in a PCA plot.

    yeah, my family is on the edge of the ughyr/hazaras in the global. just an artifact of the biased samples and low dimensionality.

  2. also, me

    67.66 east asians
    67.47 siberians
    67.39 oceanians
    67.33 s. americans
    67.20 n. americans
    67.18 c/s. asians
    66.56 n. europeans
    66.47 s. europeans
    66.38 n. easterner
    65.78 n. african
    64.15 n. african
    64.04 s. african
    64 c. africans
    63.99 w. africans

    1. Interesting that you are closest to East Asians, though it makes sense considering their population groups.

      Also your similarity measures are much higher than mine. Even your C/S Asian one (#6 on your list) is higher than mine (#1 on my list). But that’s old news now.

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