Race and Genetics

The Relationship Between Race and Genetics

• Race is a social construct that has changed over time and varies across different societies and regions.

• Human genetic variation is mostly clinal, with 99.9% of genetic code being identical between individuals, and there are no clear boundaries between groups.

• The concept of race has been used to justify social inequalities associated with race, despite the fact that patterns of human variation do not map onto socially recognized categories of race.

• There is an ongoing scientific debate regarding the definition and meaning of race in genetic and biomedical research.

• Genetic variation arises from mutations, natural selection, gene flow, and the reshuffling of genes through sexual reproduction.

• Human phenotypes are highly polygenic and are influenced by both genetics and the environment.

• Nucleotide diversity between humans is approximately 0.1%, and there are around ten million single nucleotide polymorphisms (SNPs) in the human population.

• Structural variation accounts for more human genetic variation than single nucleotide diversity, with approximately 0.4-0.6% of the genomes of unrelated people differing.

• Much scientific research has been organized around the question of whether or not there is a genetic basis for race, but there is broad consensus across the biological and social sciences that race is a social construct, not an accurate representation of human genetic variation.

• Genetic testing is used to examine and quantify genetic subgroups, including cluster and principal components analysis.

• Genetic distance measures divergence between species or populations and significantly correlates to geographic distance between populations.

• Distance may be the result of physical boundaries restricting gene flow, such as islands, deserts, mountains, or forests.Race and Genetics: Overview and Critiques

• Population genetics uses the comparison of genetic variability within and between populations, measured by FST values ranging from 0 to 1.

• The average FST distance between human races is about 0.125, indicating a higher coefficient of kinship between unrelated individuals of the same race than mixed-race half-siblings.

• Critiques of FST point out that it fails to identify important variation and cannot distinguish between high migration and recent shared history.

• Anthropologists argue that while genetic variation roughly corresponds to race, it is true for almost all geographically distinct populations and the cluster structure of genetic data is dependent on the initial hypotheses of the researcher.

• Geographic and historical analyses attempt to identify places of origin and possible causes of genetic variation in an area, and results are supported if they agree with research from other fields like linguistics or archeology.

• Self-identification studies find nearly perfect correspondence between genetic cluster and self-identified race/ethnicity, but correspondence does not mean that a cluster or group corresponds to only one ethnic group.

• Genetic distances generally increase continually with geographic distance, making any dividing line arbitrary, and cluster analysis has been criticized because of the number of clusters to search for is decided in advance.

• Ancestry-informative markers (AIMs) are a genealogy tracing technology that has come under criticism due to its reliance on reference populations and setting thresholds for frequency.

• Statistical differences between racial groups in susceptibility to certain diseases exist, but using these associations in the practice of medicine has led doctors to overlook or misidentify disease.

• Information about a person's population of origin may aid in diagnosis, and adverse drug responses may vary by group, leading some physicians to consider a patient's race in choosing the most effective treatment.

• Some scientific journals require more rigorous scrutiny of population variables, and human geneticists have mostly abandoned the term "race" in recent years.

• Self-identified race is of greater use in medicine as it correlates strongly with risk-related exposomes that are potentially heritable when they become embodied in the epigenome, but the effects of discrimination do not offer a complete explanation for differential rates of disease and risk factors between racial groups.

• Racial naturalism is the view that racial differences are biologically determined and significant, but it has been challenged by critiques arguing that race is a social construct and not a biological fact.Controversies Surrounding the Biological Reality of Race

• Proponents of racial classifications argue that they are grounded in objective patterns of genetic similarities and differences.

• There are four main objections to this view: semantic, metaphysical, methodological, and visibility objections.

• Semantic objections argue that the populations picked out in population-genetic research are not races and do not correspond to what "race" means in the United States.

• Metaphysical objections argue that human genetic clustering results do not support the biological reality of race.

• Methodological critics reject racial naturalism because of concerns relating to the experimental design, execution, or interpretation of population-genetic research.

• The visibility objection refutes the claim that US racial groups can be defined by visible traits, such as skin color and physical attributes.

• Some philosophers argue that US racial groups are not biologically real because they are not objectively real in the sense of existing independently of some mental state of humans.

• David J. Witherspoon and colleagues argue that people of the same race vary from one another, and that caution should be used when using geographic or genetic ancestry to make inferences about individual phenotypes.

• Anthropologist Norman Sauer argues that the successful assignment of race to a skeleton is not a vindication of the race concept, but rather a prediction that an individual, while alive, was assigned to a particular socially constructed 'racial' category.

• Genetics is often not the predominant determinant of disease susceptibilities, even though they might correlate with specific socially defined categories.

• Socio-economic factors can play a significant role in explaining variations of disease prevalence between populations.

• An individual's self-identified race is complex and depends on psychological, cultural, and social factors, making it a poor proxy for genetic ancestry.