8/11/2019 Human Genomes by the Thousands-1st Lecture Info

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Many researchers note a striking under-representation of non-white and non-Asiangenomics projects. Only a handful of Africanand South American genomes are complete;more are planned in population studies.

The United States isthe country with themost high-throughputsequencing machines.

Labs in NorthAmerica will finishsome 9,000genomes by theend of next year.

N O R T H

A M E R I C A

,35

9,029

To understand populations

Comparing lots of genomes lets researchers

identify points at which one genome differs

from the next. Costs may be falling, but

sequencing and data analysis are still pricey.

So most researchers face a trade-off between

the number of subjects and the accuracy in

the sequences they can afford. For projects

examining how populations commonly differ,

sequencing a large number of individuals at

relatively low accuracy or depth of coverage is

enough. About 900 genomes sequenced so far

by the 1000 Genomes Project have been read

three times on average.

To understand disease

Researchers trying to uncover rare disease-

linked mutations perhaps limited to just

one family or an individual need precision,

typically sequencing each genome 30

times on average. Cancer genomes, many

sequenced under the auspices of large

collaborations, account for a sizeable chunk of

high-coverage genome sequences completed

to date. Projects scrutinizing people with

diabetes, Crohns disease and other disorders

are starting to emerge. Analysing all the

genome data is a huge challenge, as is turning

genetic discoveries into clinical benefits.

Low & medium coverage

(15and below)1,756

High coverage

(30and above)974

GENOME

ACCURACY

Cost still limits the accuracy withwhich genomes are sequenced.

GRAPHICSBYNIKSPENCER;DATACOMPILEDBYALLAK

ATSNELSON

KEY

500 genomesby the end ofOctober 2010

500 genomesby the endof 2011

Number ofhigh-throughputsequencersin the region

Genomes by

the thousandTen years ago, two fingers were enough tocount the number of sequenced humangenomes. Until last year, the fingers on twohands were enough. Today, the rate of suchsequencing is escalating so fast it is hard tokeep track. Natureattempted nevertheless:we asked more than 90 genomics centres

and labs to estimate the number of humangenome sequences they have in the works.Although far from comprehensive, the tallyindicates that at least 2,700 human genomeswill have been completed by the end of thismonth, and that the total will rise to morethan 30,000 by the end of 2011.

Why scientists want tens of thousands of genomes and more

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SOURCE:JAMESHADFIELD&NICKLOMAN

Labs in Australia have completedmore than 40 genomes, mostly aspart of cancer sequencing projects.They plan to finish well over 100genomes by the end of next year.

Individual labs may still find it cheaper and easierto outsource a human genome to a power-housesequencing service provider. The BGI in Shenzen,which has global expansion plans, predicts that itsmachines will have completed some 10,000 to 20,000human genomes by the end of 2011.

The latest sequencingtechnology is no longerconcentrated at a few majorcentres. In Britain, theWellcome Trust SangerInstitute in Hinxton houses38 of the countrys high-throughput sequencers, andthe rest are scattered overan additional 32 sites.Falling costs mean that ahuman genome is withinthe reach of individual labs.

E U R O P E

A S I A

8

101

11

2

3

1

1 5

5

1

19

2

2

18

8

1

1

28

17

4

16

2

21

,039

509

5,953

5,376

POWER TO THE PEOPLETHE RISE OF GENOME FACTORIES

Number ofhigh-throughput

sequencers inthe region

With at least 80Illumina machines,the BGI holds mostof the regionssequencing power.

56

19

12

103

UK machines willhelp to sequence2,500 genomes aspart of the 1000Genomes Project.

To understand individuals

The rate at which human genomes

are being sequenced at least in

mega-projects will probably slow

once researchers have extracted

most of the common variation shared

by populations and diseases. But

individuals are genetically unique.

If the cost of a genome sequence

becomes trivial and the benefits of

knowing one increase (through gene-

tailored medicine), then personal

genome sequencing will continue to

push the genome count up and up.

TYPE OF

PROJECT

Disease-specific projects make up morethan half of the complete genomes.

Population1,230

Otherdiseases

916

Cancer485

Other/unknown55

Personal44

NATURE.COM

For more on humangenomes see:www.nature.com/humangenome

METHODS: Our survey focused on large, academic projectsrather than individual labs; we included complete genomesequences, both high- and low-coverage, and excluded partial(exome) sequences. The list excludes all biotechnology andpharmaceutical companies and most sequencing serviceproviders, which do not disclose their work. The sequencerlocations, based on a user-generated map at go.nature.com/

b74acy, includes some 6070% of all machines.

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