Tag: ibd

Another “Pre-Yamnaya” sample from the Northern Caucasus?

wang-caucasus-maykop

I have updated the Ancient DNA Dataset, including a lot of new information from – among other sources – the latest version of Reich Lab curated Dataset, now renamed Allen Ancient DNA Resource (AADR). This includes new columns:

  1. Object-ID: I am now using whenever possible the Master-ID; Version-ID for a quick identification of the ‘best’ sample to include in SmartPCA or ADMIXTURE runs; and Index as a key with a unique reference number for each sample. That should make for enough stable references for any external tool to use the data.
  2. mtDNA: Added mtDNA coverage
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IBD sharing between Corded Ware and Yamnaya-related populations

yamnaya-corded-ware

Oral communication Ancient DNA and the New Science of the Human Past by David Reich (March 3, 2021).

I noticed this interesting slide called “Caught red-handed”, at approximately 45m 17s, where David Reich asserts that sampled Corded Ware populations had many “close cousins” with Yamnaya-related populations “within generations”. The method could also be used, always according to Reich, to identify “who the Yamnaya mixed with to form groups like Corded Ware”.

NOTE. Notice also the the number of new sampled individuals from Khvalynsk, Ekaterinovka, and new Yamnaya groups from Chelyabinsk, Urals, Volga, Don, Moldova, and Romania.

This represents the … Read the rest “IBD sharing between Corded Ware and Yamnaya-related populations”

Mongolian tribes cluster with East Asians, closely related to the Japanese

mongolian-sampling

New paper behind paywall Whole-genome sequencing of 175 Mongolians uncovers population-specific genetic architecture and gene flow throughout North and East Asia, by Bai et al Nature Genetics (2018).

Interesting excerpts (emphasis mine):

Genome sequencing, variant calling, and construction of the Mongolian reference panel. We collected peripheral blood with informed consent from 175 Mongolian individuals representing six distinct tribes/regions in northern China and Mongolia, including the Abaga, Khalkha, Oirat, Buryat, Sonid, and Horchin tribes.

The fixation index (FST) was used to estimate pairwise genetic differentiation among our Mongolian samples and 26 modern human populations selected from 1000G (…) the Mongolian

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Inca and Spanish Empires had a profound impact on Peruvian demography

peru-population-history

Open access Evolutionary genomic dynamics of Peruvians before, during, and after the Inca Empire by Harris et al., PNAS (2018) 201720798 (published ahead of print).

Abstract (emphasis mine):

Native Americans from the Amazon, Andes, and coastal geographic regions of South America have a rich cultural heritage but are genetically understudied, therefore leading to gaps in our knowledge of their genomic architecture and demographic history. In this study, we sequence 150 genomes to high coverage combined with an additional 130 genotype array samples from Native American and mestizo populations in Peru. The majority of our samples possess greater than 90% Native

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Mitochondrial DNA unsuitable to test for IBD, and undersampling genomes show biased time and rate estimates

Two interesting papers questioning previous methods have been published.

Open access Mitochondrial DNA is unsuitable to test for isolation by distance, by Teske et al. Scientific Reports (2018) 8:8448.

Abstract (emphasis mine):

Tests for isolation by distance (IBD) are the most commonly used method of assessing spatial genetic structure. Many studies have exclusively used mitochondrial DNA (mtDNA) sequences to test for IBD, but this marker is often in conflict with multilocus markers. Here, we report a review of the literature on IBD, with the aims of determining (a) whether significant IBD is primarily a result of lumping spatially discrete

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Holocene rise in mobility in at least three stages: Strong link between technological change and human mobility in Western Eurasia

estimating-mobility

New interesting article at PNAS: Estimating mobility using sparse data: Application to human genetic variation, by Loog et al (2017).

Download links and supplemental information.

Significance

Migratory activity is a critical factor in shaping processes of biological and cultural change through time. We introduce a method to estimate changes in underlying migratory activity that can be applied to genetic, morphological, or cultural data and is well-suited to samples that are sparsely distributed in space and through time. By applying this method to ancient genome data, we infer a number of changes in human mobility in Western Eurasia, including

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