The domestication and dispersal of goats

[Angela]

See:
Kevin G. Daily et al

http://science.sciencemag.org/content/361/6397/85.full

Ancient goat genomes reveal mosaic domestication in the Fertile Crescent



How humans got their goats

Little is known regarding the location and mode of the early domestication of animals such as goats for husbandry. To investigate the history of the goat, Daly et al. sequenced mitochondrial and nuclear sequences from ancient specimens ranging from hundreds to thousands of years in age. Multiple wild populations contributed to the origin of modern goats during the Neolithic. Over time, one mitochondrial type spread and became dominant worldwide. However, at the whole-genome level, modern goat populations are a mix of goats from different sources and provide evidence for a multilocus process of domestication in the Near East. Furthermore, the patterns described support the idea of multiple dispersal routes out of the Fertile Crescent region by domesticated animals and their human counterparts.

Abstract

Current genetic data are equivocal as to whether goat domestication occurred multiple times or was a singular process. We generated genomic data from 83 ancient goats (51 with genome-wide coverage) from Paleolithic to Medieval contexts throughout the Near East. Our findings demonstrate that multiple divergent ancient wild goat sources were domesticated in a dispersed process that resulted in genetically and geographically distinct Neolithic goat populations, echoing contemporaneous human divergence across the region. These early goat populations contributed differently to modern goats in Asia, Africa, and Europe. We also detect early selection for pigmentation, stature, reproduction, milking, and response to dietary change, providing 8000-year-old evidence for human agency in molding genome variation within a partner species.

 

[Ygorcs]

See:
Kevin G. Daily et al

http://science.sciencemag.org/content/361/6397/85.full

Ancient goat genomes reveal mosaic domestication in the Fertile Crescent



How humans got their goats

Little is known regarding the location and mode of the early domestication of animals such as goats for husbandry. To investigate the history of the goat, Daly et al. sequenced mitochondrial and nuclear sequences from ancient specimens ranging from hundreds to thousands of years in age. Multiple wild populations contributed to the origin of modern goats during the Neolithic. Over time, one mitochondrial type spread and became dominant worldwide. However, at the whole-genome level, modern goat populations are a mix of goats from different sources and provide evidence for a multilocus process of domestication in the Near East. Furthermore, the patterns described support the idea of multiple dispersal routes out of the Fertile Crescent region by domesticated animals and their human counterparts.

Abstract

Current genetic data are equivocal as to whether goat domestication occurred multiple times or was a singular process. We generated genomic data from 83 ancient goats (51 with genome-wide coverage) from Paleolithic to Medieval contexts throughout the Near East. Our findings demonstrate that multiple divergent ancient wild goat sources were domesticated in a dispersed process that resulted in genetically and geographically distinct Neolithic goat populations, echoing contemporaneous human divergence across the region. These early goat populations contributed differently to modern goats in Asia, Africa, and Europe. We also detect early selection for pigmentation, stature, reproduction, milking, and response to dietary change, providing 8000-year-old evidence for human agency in molding genome variation within a partner species.

That's an interesting conclusion if you consider that the genetic evidences point simultaneously to a very rich genetic structure in early Neolithic West Asia (supposedly Levantines and Iranians were as distinct as modern Europeans and Chinese), but now also to a Neolithic expansion in multiple waves and routes from the first places of animal and plant domestication. But we see surprisingly a pretty high homogeneity in the Neolithic expansionto Europe, Caucasus, India and other places (AFAIK, correct me if I'm wrong). So should we assume that in the ancient Near East there were large homogeneous population structures with very strict genetic borders between them and few intermediary groups? Intriguing.

 

[Angela]

That's an interesting conclusion if you consider that the genetic evidences point simultaneously to a very rich genetic structure in early Neolithic West Asia (supposedly Levantines and Iranians were as distinct as modern Europeans and Chinese), but now also to a Neolithic expansion in multiple waves and routes from the first places of animal and plant domestication. But we see surprisingly a pretty high homogeneity in the Neolithic expansionto Europe, Caucasus, India and other places (AFAIK, correct me if I'm wrong). So should we assume that in the ancient Near East there were large homogeneous population structures with very strict genetic borders between them and few intermediary groups? Intriguing.

From what I recall, the Anatolian farmers who went to Europe were a mix: some Levant Neolithic in them and also some UHG related to Villabruna type hunter-gatherers I think, and even a bit of Iran Neo/CHG.

The real mixing, however, came with the Chalcolithic and Bronze Age.

Plus, even if the Basal Eurasian in them is only about 23% according to the revised figures put out by the Reich Lab people, it's still ancestry which the western farmers and the Iran farmers shared, yes?

 

[Ygorcs]

From what I recall, the Anatolian farmers who went to Europe were a mix: some Levant Neolithic in them and also some UHG related to Villabruna type hunter-gatherers I think, and even a bit of Iran Neo/CHG.

The real mixing, however, came with the Chalcolithic and Bronze Age.

Plus, even if the Basal Eurasian in them is only about 23% according to the revised figures put out by the Reich Lab people, it's still ancestry which the western farmers and the Iran farmers shared, yes?

Yes, but most of those admixture events (with UHG and BE) happened most probably during the Near Eastern Mesolithic or even before the Holocene era, so I don't think these evidences of much earlier intermixing have a lot of direct relevance to the issue of multiple dispersals of farming and animal husbandry coinciding with a period of relative regional homogeneity of the genetic structures in the Near East, which are phenomena of the early Neolithic era. You correctly reminded us that the ANF that migrated to Europe also had some Levant Neolithic and Iranian Neolithic/CHG, but as far as I remember the proportions were really low, not indicative of much inter-regional contact despite all the various (and varied) dispersal routes.

I mean, what surprised me is that there was probably a widespread dispersal/expansion from multiple centers of plant/animal domestication, but nonetheless by the mid Neolithic the distinct genetic clusters (ANF, Levant_Neo, Iran_Neo) were still relatively unmixed with each other.

And another intriguing point is that there was apparently a significant (not complete) homogeneity within each of those regions (Anatolia, Levant, Iran) to the point that the farmer diaspora deriving from each of them represent broadly the same population structure, and not several genetically different populations still diverse and in an ongoing process of mixing with each other.

It's as if those 3 clusters had enough time to mature, with extensive internal mixing and homogeneization, but not much "exotic" influx, before they boomed in the Neolithic.

 

[davef]

Alright!! A goat study!!!!

 

[Angela]

Yes, but most of those admixture events (with UHG and BE) happened most probably during the Near Eastern Mesolithic or even before the Holocene era, so I don't think these evidences of much earlier intermixing have a lot of direct relevance to the issue of multiple dispersals of farming and animal husbandry coinciding with a period of relative regional homogeneity of the genetic structures in the Near East, which are phenomena of the early Neolithic era. You correctly reminded us that the ANF that migrated to Europe also had some Levant Neolithic and Iranian Neolithic/CHG, but as far as I remember the proportions were really low, not indicative of much inter-regional contact despite all the various (and varied) dispersal routes.

I mean, what surprised me is that there was probably a widespread dispersal/expansion from multiple centers of plant/animal domestication, but nonetheless by the mid Neolithic the distinct genetic clusters (ANF, Levant_Neo, Iran_Neo) were still relatively unmixed with each other.

And another intriguing point is that there was apparently a significant (not complete) homogeneity within each of those regions (Anatolia, Levant, Iran) to the point that the farmer diaspora deriving from each of them represent broadly the same population structure, and not several genetically different populations still diverse and in an ongoing process of mixing with each other.

It's as if those 3 clusters had enough time to mature, with extensive internal mixing and homogeneization, but not much "exotic" influx, before they boomed in the Neolithic.

Kilinc et al is a good paper for looking at genetic diversity in the Near East in the Neolithic. There is a change from Aceramic to Pottery Neolithic.
https://www.sciencedirect.com/science/article/pii/S0960982216308508

"Notably, Boncuklu displayed lower amounts of this ‘‘southern component’’ compared to individuals from Tepecik-C¸ iftlik and Barcın (Mann-Whitney U test, p < 0.001; Data S3), implying an influx of ‘‘southern component’’ alleles into late Aceramic and/or Pottery Neolithic settlements in Anatolia. This finding was also in line with higher genetic diversity in the later Neolithic Anatolian populations compared to Boncuklu (Figures 2B and 2C)."

"]. Nearly 1,500 years later, Tepecik-C¸ iftlik and Barcın, fully established Neolithic populations practicing mixed farming (and within 200 km east and 400 km northwest of Boncuklu, respectively), were significantly more diverse (Figure 2B). Part of this increased genetic diversity could be linked to (1) putative southern gene flow (Figure 3A) that could be related to the Aceramic Neolithic to Pottery Neolithic transition in the Neolithic Levant or could be related to widespread interactions in the late Aceramic Neolithic between central Anatolia and the Fertile Crescent in the late Pre-Pottery Neolithic B [26]; (2) migration from the east related to similar factors of inter-regional exchanges (Figure S3D); and (3) admixture among local populations. Southern and eastern gene flow into Tepecik-C¸ iftlik is consistent with the site’s presumed role as an obsidian hub and its cultural links with the Levant and might have started already before the Pottery Neolithic [15, 16]. For Barcın, these results are also in line with archaeological evidence indicating cultural influx from central Anatolia [27]. This diverse Neolithic population most likely served as one of the sources for the well-documented wave of Neolithic migration to Europe."

There was less movement from the east (CHG/Iran Neo type ancestry), but it's still there. That's why Otzi has so much of the eastern variety. He descends at least in part from a slightly later movement to Europe.

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The definitive work, though, is, I think, the Lazaridis et al 2016 paper. According to that paper, Anatolia Neolithic is about 1/3 Levant Neolithic and a similar proportion of Iran Neo.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5003663/

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Still, the larger point is correct if I'm understanding you correctly. The Levant Neolithic was very different from the Iran Neolithic. The "mixing" seems to have taken place in Anatolia. Then, the Anatolian like "western" Neolithic went into Europe during the Neolithic. Iran Neo went in another direction, into India and Central Asia.