Home

Ancient DNA and human history

Leave a comment

Republication from  pnas.org

trhtdjdtyjntdyj

We review studies of genomic data obtained by sequencing hominin fossils with particular emphasis on the unique information that ancient DNA (aDNA) can provide about the demographic history of humans and our closest relatives. We concentrate on nuclear genomic sequences that have been published in the past few years. In many cases, particularly in the Arctic, the Americas, and Europe, aDNA has revealed historical demographic patterns in a way that could not be resolved by analyzing present-day genomes alone.

More

Advertisements

Admixture into and within sub-Saharan Africa

Leave a comment

Republication  from elifesciences.org

 

Similarity between two individuals in the combination of genetic markers along their chromosomes indicates shared ancestry and can be used to identify historical connections between different population groups due to admixture. We use a genome-wide, haplotype-based, analysis to characterise the structure of genetic diversity and gene-flow in a collection of 48 sub-Saharan African groups. We show that coastal populations experienced an influx of Eurasian haplotypes over the last 7000 years, and that Eastern and Southern Niger-Congo speaking groups share ancestry with Central West Africans as a result of recent population expansions.

More

Neolithic and Bronze Age migration to Ireland

Leave a comment

Republication from pnas.org

Significance

Modern Europe has been shaped by two episodes in prehistory, the advent of agriculture and later metallurgy. These innovations brought not only massive cultural change but also, in certain parts of the continent, a change in genetic structure. The manner in which these transitions affected the islands of Ireland and Britain on the northwestern edge of the continent remains the subject of debate. The first ancient whole genomes from Ireland, including two at high coverage, demonstrate that large-scale genetic shifts accompanied both transitions. We also observe a strong signal of continuity between modern day Irish populations and the Bronze Age individuals, one of whom is a carrier for the C282Y hemochromatosis mutation, which has its highest frequencies in Ireland today.

Abstract

The Neolithic and Bronze Age transitions were profound cultural shifts catalyzed in parts of Europe by migrations, first of early farmers from the Near East and then Bronze Age herders from the Pontic Steppe. However, a decades-long, unresolved controversy is whether population change or cultural adoption occurred at the Atlantic edge, within the British Isles. We address this issue by using the first whole genome data from prehistoric Irish individuals.

More

Large-scale recent expansion of European patrilineages shown by population resequencing

Leave a comment

Republication from  nature.com

Phylogeny and geographical distribution of European MSY lineages.

(a) Maximum-parsimony tree of European MSY lineages defined here by resequencing. Branch lengths are proportional to molecular divergence among haplotypes. Key mutation names are given next to some branches, and haplogroup names20 in the coloured bar below. Three sporadic haplogroups are coloured in black. The grey box within hg R1b-M269 shows the star phylogeny referred to in the text. (b) Map with pie-charts showing frequencies of Y-chromosome haplogroups (defined and coloured as in part a) in 17 populations from Europe and the Near East. Population abbreviations are as follows: bas: Basque; bav: Bavaria; CEU: Utah residents with Northern and Western European ancestry from the CEPH collection (France); den: Denmark; eng: England; fri: Frisia; gre: Greece; hun: Hungary; ire: Ireland; nor: Norway; ork: Orkney; pal: Palestinians; saa: Saami; ser: Serbia; spa: Spain; TSI: Toscani in Italia (Italy); tur: Turkey.

The proportion of Europeans descending from Neolithic farmers 10 thousand years ago (KYA) or Palaeolithic hunter-gatherers has been much debated. The male-specific region of the Y chromosome (MSY) has been widely applied to this question, but unbiased estimates of diversity and time depth have been lacking. Here we show that European patrilineages underwent a recent continent-wide expansion. Resequencing of 3.7 Mb of MSY DNA in 334 males, comprising 17 European and Middle Eastern populations, defines a phylogeny containing 5,996 single-nucleotide polymorphisms. Dating indicates that three major lineages (I1, R1a and R1b), accounting for 64% of our sample, have very recent coalescent times, ranging between 3.5 and 7.3 KYA. A continuous swathe of 13/17 populations share similar histories featuring a demographic expansion starting 2.1–4.2 KYA. Our results are compatible with ancient MSY DNA data, and contrast with data on mitochondrial DNA, indicating a widespread male-specific phenomenon that focuses interest on the social structure of Bronze Age Europe.

 

More

Population genomics of Bronze Age Eurasia

Leave a comment

Republication  from  Nature

Distribution maps of ancient samples.

 

Localities, cultural associations, and approximate timeline of 101 sampled ancient individuals from Europe and Central Asia (left). Distribution of Early Bronze Age cultures Yamnaya, Corded Ware, and Afanasievo with arrows showing the Yamnaya expansions (top right). Middle and Late Bronze Age cultures Sintashta, Andronovo, Okunevo, and Karasuk with the eastward migration indicated (bottom right). Black markers represent chariot burials (2000–1800 bc) with similar horse cheek pieces, as evidence of expanding cultures. Tocharian is the second-oldest branch of Indo-European languages, preserved in Western China. CA, Copper Age; MN, Middle Neolithic; LN, Late Neolithic; EBA, Early Bronze Age; MBA, Middle Bronze Age; LBA, Late Bronze Age; IA, Iron Age; BAC, Battle Axe culture; CWC, Corded Ware culture.

.

More

British Have Changed Little Since Ice Age, Gene Study Says

Leave a comment

Republication from National Geographic News

 

By James Owen
for National Geographic News
.

Despite invasions by Saxons, Romans, Vikings, Normans, and others, the genetic makeup of today’s white Britons is much the same as it was 12,000 ago, a new book claims.

In The Tribes of Britain, archaeologist David Miles says around 80 percent of the genetic characteristics of most white Britons have been passed down from a few thousand Ice Age hunters.

Miles, research fellow at the Institute of Archaeology in Oxford, England, says recent genetic and archaeological evidence puts a new perspective on the history of the British people.

More

Older Entries