Iron Age and Anglo-Saxon genomes from East England reveal British migration history

Abstract

British population history has been shaped by a series of immigrations, including the early Anglo-Saxon migrations after 400 CE. It remains an open question how these events affected the genetic composition of the current British population. Here, we present whole-genome sequences from 10 individuals excavated close to Cambridge in the East of England, ranging from the late Iron Age to the middle Anglo-Saxon period. By analysing shared rare variants with hundreds of modern samples from Britain and Europe, we estimate that on average the contemporary East English population derives 38% of its ancestry from Anglo-Saxon migrations. We gain further insight with a new method, rarecoal, which infers population history and identifies fine-scale genetic ancestry from rare variants. Using rarecoal we find that the Anglo-Saxon samples are closely related to modern Dutch and Danish populations, while the Iron Age samples share ancestors with multiple Northern European populations including Britain.

Dating genomic variants and shared ancestry in population-scale sequencing data

“…The evolutionary history of classes of variants contributing to polygenic adaptation (for example, those affecting height [6,16,17]) or causing potential loss of gene function [18] has received attention, though rarely at the level of specific variants. Previous work on rare variants has identified ancestral connections between individuals and populations [19][20][21] and demonstrated evidence for explosive population growth [22]. Nevertheless, to date, no comprehensive effort has been made to infer the age, place of origin, or pattern of spread for the vast majority of variants.…”

Tracking human population structure through time from whole genome sequences

“…These methods estimate one or both of two important aspects of population history: i) The history of the effective population size, and ii) the history of population structure. The second aspect, which entails reconstructing the timing and dynamics of population separation requires a non-trivial choice of parameterization: While methods like diCal2 [5], as well as many methods based on the joint site frequency spectrum [8][9][10][11] use an explicit population model with split times, migration rates or admixture events, MSMC [4] introduced the concept of the relative cross coalescence rate to capture population separations in a continuously parameterized fashion. The main advantage of that approach is that it does not require the specification of an explicit model, but can be applied hypothesis-free to estimate key aspects of population separation, for example the time at which lineages are half as likely to coalesce between rather than within populations, which is often used as a heuristic estimate for the divergence time between the populations.…”

A múlt rekonstruálása a történeti genetika módszereivel

“…Ezen csoportok között megtalálhatók a bennszülött középső kőkorszaki vadászó-gyűjtögetők, a Közel-Keletről bevándorolt telepesek és az eurázsiai sztyeppékről származó nomádok, akik elözönlötték a bronzkori Európát. Amennyire lenyűgöző az európai őstörténetben a népességfejlődés dinamikája, ezt a genetikai sokféleségben, differenciációban visszalépés követte, és a bronzkorban elért arra a szintre, amelyet a mai Európában is megfigyelhetünk (Lazaridis et al, 2016 (Martiniano et al, 2016;Schiffels et al, 2016).…”