Eurogenes Blog: November 2019

Monday, November 25, 2019

Viking Age Iceland

I finally managed to get some of the Icelandic ancients from Ebenesersdóttir et al. 2018 into the Global25 datasheets (see here). Better late than never. Look for the"ISL_Viking_Age" prefix. Below is a screen cap of a Principal Component Analysis (PCA) with the new samples. It was done with an online Global25 PCA runner freely available here.

The individuals classified as unadmixed Gaels and Norse by Ebenesersdóttir et al. generally also look like it based on their Global25 coordinates.

The mixture models below, using all of the populations from the Global25 "modern pop averages scaled" datasheet, were run with an online tool freely available here. Note that the ADD DIST COL option is set to 1X. This is a useful feature for modeling the fine scale ancestry of samples that are derived from very similar populations.

Sunday, November 10, 2019

Etruscans, Latins, Romans and others

I've just added coordinates for more than 100 ancient genomes from the recently published Antonio et al. ancient Rome paper to the Global25 datasheets. Look for the population and individual codes listed here. Same links as always:

Global25 datasheet ancient scaled

Global25 pop averages ancient scaled

Global25 datasheet ancient

Global25 pop averages ancient

Thus far I've only managed to check a handful of the coordinates, so please let me know if you spot any issues. Below is a Principal Component Analysis (PCA) featuring the Etruscan and Italic speakers. I ran the PCA with an online tool specifically designed for Global25 coordinates freely available here.

Can we say anything useful about the origins of the Etruscan and early Italic populations thanks to these new genomes? Also, to reiterate my question from the last blog post, what are the genetic differences exactly between the Etruscans, early Latins, Romans and present-day Italians? Feel free to let me know in the comments below.

Update 13/11/2019: Here's another, similar PCA. This one, however, is based on genotype data, and it also highlights many more of the samples from the Antonio et al. paper. Considering these results, I'm tempted to say that the present-day Italian gene pool largely formed in the Iron Age, and that it was only augmented by population movements during later periods. The relevant datasheet is available here.

Update 13/11/2019: It seems to me that the two Latini-associated outliers show significant ancestry from the Levant, which possibly means that they're in part of Phoenician origin. These qpAdm models speak for themselves:

ITA_Ardea_Latini_IA_o
ITA_Proto-Villanovan 0.547±0.081
Levant_ISR_Ashkelon_IA2 0.453±0.081
chisq 7.573
tail prob 0.87027
Full output

ITA_Prenestini_tribe_IA_o
ITA_Proto-Villanovan 0.679±0.068
Levant_ISR_Ashkelon_IA2 0.321±0.068
chisq 7.222
tail prob 0.89033
Full output

The Proto-Villanovan singleton is also a key part of the models. Dating to the Bronze Age/Iron Age transition, she appears to be of western Balkan origin. Moreover, her steppe ancestry is probably derived directly from the Yamnaya horizon.

ITA_Proto-Villanovan
HRV_Vucedol 0.677±0.031
Yamnaya_RUS_Samara 0.323±0.031
chisq 10.397
tail prob 0.661174
Full output

The cluster made up of four early Italic speakers can be modeled with minor Proto-Villanovan-related ancestry, but, perhaps crucially, it doesn't need to be. Indeed, judging by the qpAdm output below, it's possible that almost all of its steppe ancestry came from the Bell Beaker complex, and, thus, the Corded Ware culture complex before that.

ITA_Italic_IA
Bell_Beaker_Mittelelbe-Saale 0.480±0.055
ITA_Grotta_Continenza_CA 0.411±0.042
ITA_Proto-Villanovan 0.109±0.084
chisq 10.294
tail prob 0.590205
Full output

Two out of the three available Etruscans look very similar to the Italic speakers in the above PCA plots, and yet they show a lot more Proto-Villanovan-related ancestry in my qpAdm run. The statistical fit is also relatively poor, perhaps suggesting that something important is missing.

ITA_Etruscan
Bell_Beaker_Mittelelbe-Saale 0.186±0.081
ITA_Grotta_Continenza_CA 0.283±0.064
ITA_Proto-Villanovan 0.531±0.126
chisq 17.175
tail prob 0.143143
Full output

Interestingly, the Etruscan outlier with significant North African admixture (proxied in my run by MAR_LN) doesn't need to be modeled with any Bell Beaker ancestry.

ITA_Etruscan_o
ITA_Proto-Villanovan 0.675±0.057
MAR_LN 0.325±0.057
chisq 14.864
tail prob 0.315912
Full output

Update 17/11/2019: The spatial maps below show how three groups of ancient Romans (from the Imperial, Late Antiquity and Medieval periods) compare to present-day West Eurasian populations in terms of their Global25 coordinates. The hotter the color, the higher the similarity. More here.

See also...

Getting the most out of the Global25

Thursday, November 7, 2019

What's the difference between ancient Romans and present-day Italians?

The first paper on the genomics of ancient Romans was finally published today at Science [LINK]. It's behind a paywall, but the supplementary info is freely available here. Below is a quick summary of the results courtesy of the accompanying Ancient Rome Data Explorer.

I'm told that the genotype data from the paper will be online within a day or so at the Pritchard Lab website here. I'll have a lot more to say about ancient Romans and present-day Italians after I get my hands on it.

See also...

Etruscans, Latins, Romans and others

Tuesday, November 5, 2019

Modeling your ancestry has never been easier

An exceedingly simple, yet feature-packed, online tool ideal for modeling ancestry with Global25 coordinates is freely available HERE. It works offline too, after downloading the web page onto your computer. Just copy paste the coordinates of your choice under the "source" and "target" tabs, and then mess around with the buttons to see what happens. The screen caps below show me doing just that.

Another free, easy to use online tool that works with Global25 coordinates is the Principal Component Analysis (PCA) runner HERE. Below is a screen cap of me checking out one of the many PCA that it offers.