Feasible Global 25 models

As promised, I will now be modelling contemporary Irish using a host of ancient samples which I believe reflect best the population genomic history of Ireland using the best admixture tools at my disposal.

For the first plausible model I will start off with the most basic threefold Steppe_EMBA/EEF/WHG using various proxies available currently on the Global 25 database. Nothing fancy.

For this first run I will be using yamnaya samples from samara kurgans, neolithic samples from Barcin Hoyuk, Turkey and a mesolithic sample from Loschbour, Belgium as a standin for WHG input.

 "distance%=5.5949"

 Irish:

Yamnaya_Samara,49.8

Barcin_N,37

WHG,13.2

Not bad as far as fits go, but the target distance is a tad too high. Around 2-3% is the optimum range we want to be reaching, but I am fairly happy with this result. However there are samples available on Global 25 to me where I can get a closer fit than this.

"distance%=4.5636"

Irish:

RUS_Poltavka,48.6

UKR_N_o,37

WHG,14.4

The results are near identical for this model, however the fit has drastically improved somewhat. Probably due to sharing more recent drift with these samples from poltavka (essentially descendants of the yamnaya who continued to live on the pontic steppe instead of migrating west), and the neolithic outlier sample from Tripolye, Ukraine.

For this next run I will be using more recent populations which should yield better results, this model will consist of Corded Ware samples from Germany, and EEF samples from Globular Amphora and Grooved Ware horizons respectively. The former from Poland and the latter from Ballynahatty, Ireland.

"distance%=3.8649"

     Irish:

Corded_Ware_DEU,65

POL_Globular_Amphora,35

IRL_MN,0

Unsurprisingly, modern Irish do not score anything from Ballynahatty, as her population was near totally replaced by incoming Rhenish beakers, who were themselves most likely of single grave origin, although somewhat more farmer shifted, perhaps harbouring some funnelbeaker input from Holland. Even when using these beakers as a proxy instead of CWC the same happens.

"distance%=2.934"

      Irish:

Bell_Beaker_NLD,79.8

POL_Globular_Amphora,20.2

IRL_MN,0

As you can see Irish have shown a great deal of continuity since the Bronze age, although there has been a pretty obvious bit of turnover since then from a southern shifted source.

Hmmmmmm I wonder what could've caused this? 

I think I may know the answer, which I will discuss in a later post.