Use and Misuse of Race Information in Genomic Research Tesfaye B. - - PowerPoint PPT Presentation

Use and Misuse of Race Information in Genomic Research

Tesfaye B. Mersha, PhD Assistant Professor Division of Asthma Research

Cincinnati Children’s Hospital Medical Center University of Cincinnati

Every indicator of well-being shows disparities by race. Race: physical markers (e.g. color)- it combines both genetic and environmental determinant of health. Ethnicity: Cultural markers- shared religion, race, language, or place of origin. Ancestry: Genetic markers- it is a statistical product and refers to an individual’s genetic origin/background.

Why race matters?

 Human origin and variation  Race versus ancestry

 Does race exist, and matters?

 Admixed ancestry to study health disparities  Ancestry and its measures AncestrySNPminer…  Discussion points

Outline

Q1: Can scientist determine a person’s race by looking at his or her DNA? Q2: What does skin color tell you about a person?

• Q3. Are there race-specific genes?
• Q4. Can ancestry be a substitute for defining race or vice versa?
• Q5. Is ancestry, rather than race, a better predictor of disease

risk?

• Q5. Is knowing the patient’s race helps the doctor make an

accurate diagnosis?

Potential questions about race and ancestry

Human Origin

Lucy

The ‘First Human’ discovered in Ethiopia KENYA

We all are Ethiopians: Either living in Ethiopia or in recent exile!

http://www.academyll.org/wordpress/assets/Human-Migration-chart.pdf

Human Origin

ATTGCAATCCGTGG...ATCGAGCCA…TACGATTGCACGCCG… ATTGCAAGCCGTGG...ATCTAGCCA…TACGATTGCAAGCCG… ATTGCAAGCCGTGG...ATCTAGCCA…TACGATTGCAAGCCG… ATTGCAATCCGTGG...ATCGAGCCA…TACGATTGCACGCCG… ATTGCAAGCCGTGG...ATCTAGCCA…TACGATTGCAAGCCG…

Genetic variation in SNPs

How is variation distributed within and between populations

Mersha, Human Genomics 2011 85% 15% Asian

White

85-90% 10-15%

• Watson and Venter share more alleles with Kim than with each other

Comparison of completely sequenced individuals

Seong-jin Kim James Watson Craig Venter

1,715,851

Asian ancestry

European ancestry

Genome Res 2009, 19(9):1622-9

• Geographic ancestry doesn’t correspond to genetic ancestry
• The best way to know a person’s DNA is to study that person’s DNA

not his/her race or geographic ancestry.

Genetic variation race or phenotypic variation

http://blogs.gonomad.com/readuponit/2007/07/tall-meets-short-in-china.html

Genetics and race

Who is Self-identified black, Latino, white?

Human diversity forms a gradient rather than discrete clusters

4

• 6
• 4
• 2

2 4 4

https://www.youtube.com/watch?v=CRcex9NEJZE

Self-reported race and admixed ancestry

NEJM, 354;4 (2006)

Broad peak for self-reported blacks due to admixture and absence of a single origin.

Ancestry proportion of European and African Americans across the United States

The American Journal of Human Genetics 96 (1): 37-53, 2015.

• EA with African ancestry are found at much higher frequencies in southern states.
• African ancestry among self-reported AAs are found highest in southern states,

especially South Carolina and Georgia.

• 23andMe- genetic testing company with over 800,000 customers
• about 80% of given their permission to participate in this study
• 5,269 self-reported AAs and 148,789 EAs and >1/2 M SNPs

European Americans African Americans

Self-reported race is NOT a good proxy for ancestry

Wayne Joseph, Principal of a high school from southern California

• Mr. Joseph considered himself as ‘black’ for 50

years but DNA PRINT Genomics Test finds out that he has NO African ancestry.

https://chancellorfiles.wordpress.com/

Scientific American, December 2003

Human populations have never been isolated long enough to form true biological races. If races are defined as “genetically discrete groups”, then the answer is NO. However, one can use race information to group individuals into clusters and identify factors related to health disparities.

Do human “races” exist?

Misuse of race information in genomics

• Genotype information from self-reported races are

used to infer continental racial group:

• HapMap data: YRI genotype data from Nigeria to infer the

entire African continent.

• Race comparison in disease genetics without

controlling socio-environmental risk factors.

• Application of ancestry-related variants to

psychological and health related-traits

• Ancestry-related variants perceived as undesirable--health

insurance purpose!

• there is NO white gene or black gene!

Under what conditions should we use race?

• To identify societal construct such as health and

income disparities.

• unequal treatment due to actual/perceived race.
• To identify non-genetic causes of health disparities

(shared environmental risk factors).

• Environmental exposure such as traffic pollution,

dust, cigarette smoke, etc.

Prevalence of asthma in children in the U.S.

Asthma prevalence is the highest in Puerto Rican and the lowest in Mexicans BUT both are Latino/Hispanics?

Asthma Prevalence (%)

5 10 15 20 Puerto Ricans African Americans European Americans Mexican Americans Asian Americans

Ancestry proportion: Mexicans vs. Puerto Ricans

Genome Biol. 2009;10(11):R132

European Journal of Human Genetics (2008) 16, 762–765

Income differs by ancestry

Race can’t inform the racial gap in income

Discussion points

• Human adaptation over years created population with

different skin color, hair texture---attribute to “race.”

• There is no black race gene or white race gene.
• Race and ancestry capture different information and can’t

substitute each other.

• Emphasizing group differences based ancestry could lead to

further disparities in health and healthcare outcomes

• Both ancestry and race information should be considered to shade

light on heath disparities.

• Health disparities are the product of complex interactions of

racial/ethnic information, ancestry/genes and environments.

Thank you

Funding: K01HL103165

Acknowledgements

“The classic mirror reflects skin color; but the DNA mirror reflects our common ancestors.”

Beatriz Marcheco, 2014