PR83767

REYKJAVIK, Iceland, April 23, 2020, /PRNewswire=KYODO JBN/--

- Archaic genetic fragments comprising nearly half the Neanderthal genome are

circulating in the European gene pool today

- The average European carries more than 500 such archaic fragments, including

SNPs linked to prostate cancer risk, iron retention, blood clotting speed, and

height

Scientists at deCODE genetics [https://www.decode.com/ ] and colleagues from

the Max Planck Institute and universities in Denmark and Iceland today publish

in Nature [https://www.nature.com/articles/s41586-020-2225-9 ] the first study

to use whole-genome sequence data from across a population to shed light on the

present-day legacy of interbreeding between modern and archaic humans more than

50,000 years ago. In general terms, the findings support previous estimates

that most people outside of Africa have approximately 2% archaic ancestry,

predominantly the result of repeated contact and interbreeding between groups

of Homo sapiens and multiple Neanderthal individuals. The results also show

more significant than expected genomic fragments from Denisovans, another

archaic human species that interbred with both Neanderthal and Homo sapiens.

Yet the principal significance of this study lies in the unprecedented

magnitude of data that was used to understand the nature and impact of this

archaic legacy. In its first phase, the study utilizes whole genome sequence

(WGS) data from 28,000 Icelanders, nearly ten percent of the entire population,

and 286 sub-Saharan Africans in the 1000 Genomes project. A limiting factor in

previous studies has been an overreliance on searching modern genomes for

sequence fragments derived from just three archaic individuals for whom we have

good quality sequence data: two Neanderthals and one Denisovan. The authors

here turn this approach on its head, using the African sequences as a baseline

for Homo sapiens with no introgression from Neanderthals, and against which

they compared the Icelandic sequence data. The resulting chromosomal fragments

found in Icelanders but not shared by Africans comprise a vast catalogue of 15

million putative archaic fragments.

After combining identical and overlapping fragments, the authors identified

more than 50,000 distinct archaic fragments covering 38-48% of the readable

genome. These contain nearly 400,000 single-letter sequence variants, that are

absent from the African samples. Intriguingly, in the Icelandic samples the

authors identify nearly 300 "archaic deserts" where there are no archaic

fragments; these cover nearly 25% of the genome, including the entire X

chromosome.

To better understand the phenotypic impact of the archaic variants, the deCODE

team examined them for association with 271 phenotypes in whole-genome data on

210,000 Icelanders. After winnowing suggestive associations in order to

eliminate those driven be nearby non-archaic variants, they identified five

archaic variants with genome-wide significant associations. One has previously

been linked to decreased levels of prostate specific antigen (PSA) and risk of

prostate cancer, but was not known to be of archaic origin; two decrease levels

and mass of hemoglobin; a fourth increases the time it takes for blood to clot;

and the fifth decreases height.

"Whether individually or collectively, our genome enables us to learn more

about who we are by telling us where we come from. This paper is a kind of

ancestry report for one branch of our species, and it's telling us that in this

particular neighborhood we are not just Homo sapiens but also the descendants

of ancient archaic humans – cousin species whose lineage is thus not entirely

extinct," said Kari Stefansson, CEO of deCODE and a senior author on the paper.

"We are scratching the surface of what this hybrid legacy means. What we know

is that in the 50,000 years from their time to this, our adaptability and

diversity have enabled us to mix and move, settle and thrive in every corner of

the planet as they did not. In these dark days we would do well to remember

that our differences are literally the mark of our success, and so to help each

other as best we can."

Based in Reykjavik, Iceland, deCODE is a global leader in analyzing and

understanding the human genome. Using its unique expertise in human genetics

combined with growing expertise in transcriptomics and population proteomics

and vast amount of phenotypic data, deCODE has discovered risk factors for

dozens of common diseases and provided key insights into their pathogenesis.

The purpose of understanding the genetics of disease is to use that information

to create new means of diagnosing, treating and preventing disease. deCODE is a

wholly-owned subsidiary of Amgen (NASDAQ:AMGN).

Video - https://mma.prnewswire.com/media/1158592/Neanderthal_In_All_Of_Us.mp4

Photo - https://mma.prnewswire.com/media/1158559/deCODE_genetics.jpg

Logo - https://mma.prnewswire.com/media/974116/deCODE_genetics_Logo.jpg

Contact:

Thora Kristin Asgeirsdottir

+354-894-1909

Thora.Asgeirsdottir@decode.is

SOURCE: deCODE genetics