Neil Risch

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Neil Risch
Neil Risch.jpg
Education California Institute of Technology (BS)
University of California, Los Angeles (PhD)
Known forEmphasizing links between population genetics and clinical application
Awards American Association for the Advancement of Science; California Academy of Science; National Academy of Medicine; Curt Stern Award, American Society of Human Genetics; William Allan Award, American Society of Human Genetics; Paul Hoch Award, American Psychopathological Association
Scientific career
FieldsStatistical genetics
Institutions Columbia University; Yale University; Stanford University; University of California, San Francisco

Neil Risch is an American human geneticist and professor at the University of California, San Francisco (UCSF). Risch is the Lamond Family Foundation Distinguished Professor in Human Genetics, Founding Director of the Institute for Human Genetics, and Professor of Epidemiology and Biostatistics at UCSF. He specializes in statistical genetics, genetic epidemiology and population genetics.

Contents

Risch received undergraduate training in mathematics at the California Institute of Technology (1972) and his PhD in biomathematics at UCLA (1979). Prior to his position at UCSF, he held professorial positions at Columbia University, Yale University and Stanford University. He has been referred to as "the statistical geneticist of our time." [1]

Known for his work on numerous genetic diseases including torsion dystonia, Risch emphasizes the links between population genetics and clinical application, believing that understanding human population history and disease susceptibility go hand in hand. [2]

Population genetics

Risch has conducted significant work on the nature of human differences on a geographical scale. For instance, he used social and genetic data to analyse genetic admixture from White, African, and Native American ancestry in Puerto Rico, as well as relating this to geographical variation in social status. [3]

Risch considers that genetic drift is a more compelling explanation for the carrier frequency of lysosomal storage diseases in Ashkenazi Jews than heterozygote advantage, in light of analysis of the results of recent genetic testing by his collaborators and himself. [4]

After mapping torsion dystonia by linkage disequilibrium (LD) analysis he found it was genetically dominant and was a founder mutation. Other work has focused on the genetic basis of Parkinson's disease, hemochromatosis, multiple sclerosis, diabetes, autism, epilepsy and hypertension.

Group structure

Risch has worked on the genetic structure of human groups, for instance multiple levels of structure above the level of the individual increasing in scale up to the level of race. He has translated these results into theoretical impacts on, for instance, rate of decay of linkage disequilibrium, and practical application in personalised medicine. For instance, using the Framingham data, he showed that population stratification leads not only to fewer heterozygotes than predicted from Hardy–Weinberg equilibrium but also to spouses sharing genotypes at all ancestrally informative markers, accounted for by ancestry-related assortative mating in the previous generation. [5]

Psychiatric disease

In a small twin study on Autism (around 50 twin pairs for each disease and zygosity), he argued these disorders may be less heritable than previously considered, implicating a significant family-level environment effect. [6] Similar findings were observed in family studies [7]

Homosexuality

Risch has been a prominent critic of studies on the role of genetics in sexual orientation. [8] In 1999, with colleagues he published a sib-pair study that failed to replicate a previously observed linkage [9] between male sexual orientation and Xq28 DNA markers. [10] While an independent study also found evidence at the same Xq28 location, [11] more recent very large studies failed to produce any evidence of a genetic effect in this region of the X chromosome. [12] Risch also discussed ethical issues underlying studies of socially significant traits and the under-representation of minority scientists in human genetics in his 2015 ASHG Presidential Address, [13] which received a standing ovation. [14]

Genome-wide Association Studies

With his colleague Kathleen Merikangas, Risch is possibly best known for introducing the concept of genome-wide association studies for the discovery and characterization of genetic variants of modest effects underlying complex diseases. [15] That insight revolutionized the field of human genetics, leading to a large number of genome-wide association studies and the discovery of thousands of genetic variants underlying a broad range of diseases and traits.

Risch is also known, with his colleague Catherine Schaefer, for pioneering the linkage of genome-wide genotype data to electronic health records in a large health provider database (at Kaiser Permanente Northern California), which also demonstrated the power of genome-wide association studies on a large scale. [16]

Awards

Risch has received numerous awards and recognition for his scholarship. He is an elected fellow of the American Association for the Advancement of Science (2010), the California Academy of Science (2011), and a member of the National Academy of Medicine (2010). He was the 2015 President of the American Society of Human Genetics, the 2004 recipient of the Curt Stern Award (now the Scientific Achievement Award) from the American Society of Human Genetics and the 2023 recipient of the Lifetime Achievement Award (formerly the William Allan Award) from the American Society of Human Genetics, to date the only individual to have received both. He was also the 2022 recipient of the Paul Hoch Award from the American Psychopathological Association.

Related Research Articles

<span class="mw-page-title-main">Genetics</span> Science of genes, heredity, and variation in living organisms

Genetics is the study of genes, genetic variation, and heredity in organisms. It is an important branch in biology because heredity is vital to organisms' evolution. Gregor Mendel, a Moravian Augustinian friar working in the 19th century in Brno, was the first to study genetics scientifically. Mendel studied "trait inheritance", patterns in the way traits are handed down from parents to offspring over time. He observed that organisms inherit traits by way of discrete "units of inheritance". This term, still used today, is a somewhat ambiguous definition of what is referred to as a gene.

<span class="mw-page-title-main">Biology and sexual orientation</span> Field of sexual orientation research

The relationship between biology and sexual orientation is a subject of on-going research. While scientists do not know the exact cause of sexual orientation, they theorize that it is caused by a complex interplay of genetic, hormonal, and environmental influences. However, evidence is weak for hypotheses that the post-natal social environment impacts sexual orientation, especially for males.

<span class="mw-page-title-main">Identity by descent</span> Identical nucleotide sequence due to inheritance without recombination from a common ancestor

A DNA segment is identical by state (IBS) in two or more individuals if they have identical nucleotide sequences in this segment. An IBS segment is identical by descent (IBD) in two or more individuals if they have inherited it from a common ancestor without recombination, that is, the segment has the same ancestral origin in these individuals. DNA segments that are IBD are IBS per definition, but segments that are not IBD can still be IBS due to the same mutations in different individuals or recombinations that do not alter the segment.

<span class="mw-page-title-main">Dean Hamer</span> American geneticist (born 1951)

Dean Hamer is an American geneticist, author, and filmmaker. He is known for his research on the role of genetics in sexual orientation and for a series of popular books and films that have changed scientific and public understandings and perceptions of human sexuality and gender.

<span class="mw-page-title-main">Gene–environment interaction</span> Response to the same environmental variation differently by different genotypes

Gene–environment interaction is when two different genotypes respond to environmental variation in different ways. A norm of reaction is a graph that shows the relationship between genes and environmental factors when phenotypic differences are continuous. They can help illustrate GxE interactions. When the norm of reaction is not parallel, as shown in the figure below, there is a gene by environment interaction. This indicates that each genotype responds to environmental variation in a different way. Environmental variation can be physical, chemical, biological, behavior patterns or life events.

Genetic association is when one or more genotypes within a population co-occur with a phenotypic trait more often than would be expected by chance occurrence.

<span class="mw-page-title-main">Heritability of autism</span>

The heritability of autism is the proportion of differences in expression of autism that can be explained by genetic variation; if the heritability of a condition is high, then the condition is considered to be primarily genetic. Autism has a strong genetic basis. Although the genetics of autism are complex, autism spectrum disorder (ASD) is explained more by multigene effects than by rare mutations with large effects.

<span class="mw-page-title-main">Ancestry-informative marker</span>

In population genetics, an ancestry-informative marker (AIM) is a single-nucleotide polymorphism that exhibits substantially different frequencies between different populations. A set of many AIMs can be used to estimate the proportion of ancestry of an individual derived from each population.

<span class="mw-page-title-main">Human genetic variation</span> Genetic diversity in human populations

Human genetic variation is the genetic differences in and among populations. There may be multiple variants of any given gene in the human population (alleles), a situation called polymorphism.

In molecular biology, SNP array is a type of DNA microarray which is used to detect polymorphisms within a population. A single nucleotide polymorphism (SNP), a variation at a single site in DNA, is the most frequent type of variation in the genome. Around 335 million SNPs have been identified in the human genome, 15 million of which are present at frequencies of 1% or higher across different populations worldwide.

Xq28 is a chromosome band and genetic marker situated at the tip of the X chromosome which has been studied since at least 1980. The band contains three distinct regions, totaling about 8 Mbp of genetic information. The marker came to the public eye in 1993 when studies by Dean Hamer and others indicated a link between the Xq28 marker and male sexual orientation.

<span class="mw-page-title-main">Genome-wide association study</span> Study of genetic variants in different individuals

In genomics, a genome-wide association study, is an observational study of a genome-wide set of genetic variants in different individuals to see if any variant is associated with a trait. GWA studies typically focus on associations between single-nucleotide polymorphisms (SNPs) and traits like major human diseases, but can equally be applied to any other genetic variants and any other organisms.

Genetic epidemiology is the study of the role of genetic factors in determining health and disease in families and in populations, and the interplay of such genetic factors with environmental factors. Genetic epidemiology seeks to derive a statistical and quantitative analysis of how genetics work in large groups.

<span class="mw-page-title-main">Genetics of obesity</span> Relation between obesity and genetic factors

Like many other medical conditions, obesity is the result of an interplay between environmental and genetic factors. Studies have identified variants in several genes that may contribute to weight gain and body fat distribution; although, only in a few cases are genes the primary cause of obesity.

<span class="mw-page-title-main">Aravinda Chakravarti</span> American geneticist

Aravinda Chakravarti is a human geneticist and expert in computational biology, and Director of the Center For Human Genetics & Genomics at New York University. He was the 2008 President of the American Society of Human Genetics. Chakravarti became a co-Editor-in-Chief of the journal Genome Research in 1995, and of the Annual Review of Genomics and Human Genetics' in 2005.

In genetics, association mapping, also known as "linkage disequilibrium mapping", is a method of mapping quantitative trait loci (QTLs) that takes advantage of historic linkage disequilibrium to link phenotypes to genotypes, uncovering genetic associations.

Genomic structural variation is the variation in structure of an organism's chromosome, such as deletions, duplications, copy-number variants, insertions, inversions and translocations. Originally, a structure variation affects a sequence length about 1kb to 3Mb, which is larger than SNPs and smaller than chromosome abnormality. However, the operational range of structural variants has widened to include events > 50bp. Some structural variants are associated with genetic diseases, however most are not. Approximately 13% of the human genome is defined as structurally variant in the normal population, and there are at least 240 genes that exist as homozygous deletion polymorphisms in human populations, suggesting these genes are dispensable in humans. While humans carry a median of 3.6 Mbp in SNPs, a median of 8.9 Mbp is affected by structual variation which thus causes most genetic differences between humans in terms of raw sequence data.

A human disease modifier gene is a modifier gene that alters expression of a human gene at another locus that in turn causes a genetic disease. Whereas medical genetics has tended to distinguish between monogenic traits, governed by simple, Mendelian inheritance, and quantitative traits, with cumulative, multifactorial causes, increasing evidence suggests that human diseases exist on a continuous spectrum between the two.

In genetic epidemiology, family studies are studies of whether a disease or trait "runs in a family". In other words, they are studies aimed at detecting the presence or absence of familial aggregation for the disease or trait, in which having a family history is associated with greater risk. The family research design can also be used to estimate penetrance for a given genotype, to conduct genetic association studies, and to study potential modifiers of an individual's genetic risk. If a family study shows that a trait is familial, this is a necessary, but not sufficient, criterion for it to be established as genetically influenced.

<span class="mw-page-title-main">Tara Matise</span> American geneticist

Tara Matise is an American geneticist at Rutgers University. Since 2018, she has served as chair of the Department of Genetics. Her research interests span computational genetics, data science, and human genetics. She is co-director of the Rutgers University Genetics Coordinating Center.

References

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  5. Sebro, Ronnie; Hoffman, Thomas J.; Lange, Christoph; Rogus, John J.; Risch, Neil J. (2010). "Testing for non-random mating: Evidence for ancestry-related assortative mating in the Framingham heart study". Genetic Epidemiology. 34 (7): 674–679. doi:10.1002/gepi.20528. PMC   3775670 . PMID   20842694.
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