# Huntington F. Willard
Huntington Faxon Willard is an American human geneticist known for the discovery of the XIST gene, the non-coding RNA that controls X-chromosome inactivation in mammals, and for the construction of the first human artificial chromosome in 1997.
Willard is a member of the National Academy of Sciences (elected 2013), the [National Academy of Medicine](https://www.edgepedia.org/national-academy-of-medicine) (2016), the American Academy of Arts & Sciences (2008), and the [American Association for the Advancement of Science](https://www.edgepedia.org/american-association-for-the-advancement-of-science) (2005).[1](https://www.geisinger.org/-/media/onegeisinger/pdfs/ghs/research/find-an-investigator/huntington-f-willard-cv-mar-2018) His career has moved between laboratory research and scientific leadership, with appointments at the [University of Toronto](https://www.edgepedia.org/university-of-toronto), Stanford University, Case Western Reserve University, Duke University, the Marine Biological Laboratory, the University of Chicago, and Geisinger.[2](https://www.nasonline.org/directory-entry/huntington-f-willard-82vkg4/)
| Key fact | Detail |
|---|---|
| Field | Human genetics, epigenetics, and chromatin biology |
| Known for | Discovery of the XIST gene; first human artificial chromosome (1997) |
| Training | A.B., Harvard University, 1975; Ph.D., Yale University, 1979 |
| Signature work | XIST reported in *Nature* (1991); X-inactivation profile in *Nature* (2005) |
| Honors | NAS member (2013); William Allan Award (2009); past president, American Society of Human Genetics |
## Education and early career
Willard earned his A.B. from Harvard University in 1975 and his Ph.D. from Yale University in 1979.[1](https://www.geisinger.org/-/media/onegeisinger/pdfs/ghs/research/find-an-investigator/huntington-f-willard-cv-mar-2018) Born in Boston, he graduated from [Harvard College](https://www.edgepedia.org/harvard-college) with a degree in biology.[2](https://www.nasonline.org/directory-entry/huntington-f-willard-82vkg4/) By the time he completed his doctorate he had trained with the geneticists Sam Latt and Leon Rosenberg and had published more than a dozen papers, some begun while he was still an undergraduate, according to the 2009 William Allan Award introduction in the *American Journal of Human Genetics*.[3](https://www.cell.com/ajhg/fulltext/S0002-9297(10)00004-2) According to his 2009 William Allan Award introduction in the *American Journal of Human Genetics*, after a postdoctoral fellowship with Kirby Smith at [Johns Hopkins University](https://www.edgepedia.org/johns-hopkins-university), he took his first faculty position at the University of Toronto in 1982, as assistant professor in the Department of Molecular Genetics (associate professor from 1987 to 1989).[1](https://www.geisinger.org/-/media/onegeisinger/pdfs/ghs/research/find-an-investigator/huntington-f-willard-cv-mar-2018) It was in Toronto that he began the work on human centromere organization and X-chromosome inactivation that led to the identification of XIST.[3](https://www.cell.com/ajhg/fulltext/S0002-9297(10)00004-2) He moved to Stanford University's Department of Genetics as associate professor in 1989, staying until 1992.[1](https://www.geisinger.org/-/media/onegeisinger/pdfs/ghs/research/find-an-investigator/huntington-f-willard-cv-mar-2018)
## Discovery of XIST and X-chromosome inactivation
Female mammalian cells carry two X chromosomes but need only one active; the other is silenced early in development. In 1991, a *Nature* paper from Willard's group described an X-linked gene with a previously unknown expression pattern: its transcripts were detected only from the inactive [X chromosome](https://www.edgepedia.org/x-chromosome), never from the active one.[4](https://www.nature.com/articles/349038a0) The gene was named XIST, for Xi-specific transcripts, and proposed as a candidate either involved in or uniquely influenced by X inactivation.[4](https://www.nature.com/articles/349038a0) XIST was the first gene identified within the human [X-inactivation](https://www.edgepedia.org/x-inactivation) center interval, and its product, like that of its mouse homolog Xist, is a non-coding RNA, meaning it functions as RNA rather than as a protein.[5](https://www.cell.com/cell/fulltext/S0092-8674(00)80071-9)
The discovery helped establish that large non-coding RNAs can carry out major regulatory functions in the genome.[6](https://www.amacad.org/person/huntington-faxon-willard) A related line of work defined the centromere, the structure that allows chromosomes to be inherited correctly during cell division. In 2001, a paper in *Science* from Willard's group gave a genomic and genetic definition of a functional human centromere.[7](https://doi.org/10.1016/j.ajhg.2010.01.037) In 2005, Willard's laboratory published an X-inactivation profile in *Nature* (volume 434, pages 400-404) showing extensive variability in X-linked gene expression among females, meaning that women differ substantially in which X-linked genes are active and by how much.[7](https://doi.org/10.1016/j.ajhg.2010.01.037)
## Human artificial chromosomes
In 1997, Willard's team constructed the first-generation human artificial microchromosomes, formed by introducing centromeric DNA into cells so that new centromeres assembled on it, and received international attention for building what the [Marine Biological Laboratory](https://www.edgepedia.org/marine-biological-laboratory) describes as the world's first human artificial chromosome.[7](https://doi.org/10.1016/j.ajhg.2010.01.037) • [8](https://www.mbl.edu/news/huntington-willard-named-president-and-director-marine-biological-laboratory) Such chromosomes carry a functional centromere and can be maintained in cells as an extra chromosome. In a 2000 *Science* perspective, Willard examined the potential advantages of using a human artificial chromosome to maintain expression of a therapeutic gene, since a whole chromosome could carry a gene and its regulatory elements without integrating into the patient's own DNA.[9](https://doi.org/10.1126/science.290.5495.1308) In 2004, his group showed in *Genome Biology* that heterochromatin marks, histone H3 lysine 9 methylation, and HP1α, were enriched on artificial chromosomes larger than 3 Mb but depleted on smaller ones, suggesting that only a small amount of heterochromatin may be required for centromere function.[10](https://genomebiology.biomedcentral.com/articles/10.1186/gb-2004-5-11-r89)
## Duke, the Marine Biological Laboratory, and Geisinger
According to Willard's curriculum vitae, he moved to [Case Western Reserve University](https://www.edgepedia.org/case-western-reserve-university) in 1992 as Henry Willson Payne Professor and Chairman of Genetics and Director of its Center for Human Genetics, serving as chairman until 2001 and as professor until 2002.[1](https://www.geisinger.org/-/media/onegeisinger/pdfs/ghs/research/find-an-investigator/huntington-f-willard-cv-mar-2018)
From 2003 to 2014 he was the founding Director of Duke University's Institute for Genome Sciences & Policy, where he recruited 35 faculty members across 21 departments, and held the Nanaline H. Duke Professorship from 2004 to 2014.[1](https://www.geisinger.org/-/media/onegeisinger/pdfs/ghs/research/find-an-investigator/huntington-f-willard-cv-mar-2018) • [8](https://www.mbl.edu/news/huntington-willard-named-president-and-director-marine-biological-laboratory) At Duke he also developed, as an HHMI professor from 2006, a four-year undergraduate research program in the genome sciences.[11](https://hhmi.org/scientists/huntington-f-willard)
According to the Marine Biological Laboratory's announcement, Willard became the 15th president and director of the laboratory in Woods Hole, Massachusetts, on January 1, 2015, with a concurrent faculty appointment in the Department of Human Genetics at the University of Chicago.[8](https://www.mbl.edu/news/huntington-willard-named-president-and-director-marine-biological-laboratory) He announced in 2017 that he would step down at the end of April that year, planning to return to research in genomics and precision health.[12](https://www.mbl.edu/news/huntington-f-willard-step-down-marine-biological-laboratory-president)
## Representative work
- **"X-inactivation profile reveals extensive variability in X-linked gene expression in females"**, *Nature* (2005), [doi:10.1038/nature03479](https://doi.org/10.1038/nature03479).
- **"A gene from the region of the human X inactivation centre is expressed exclusively from the inactive X chromosome"**, *Nature* (1991), [doi:10.1038/349038a0](https://doi.org/10.1038/349038a0).
## Honors, societies, and industry roles
Willard received the American Society of Human Genetics' William Allan Award in 2009 and is a past president of that society.[7](https://doi.org/10.1016/j.ajhg.2010.01.037) • [2](https://www.nasonline.org/directory-entry/huntington-f-willard-82vkg4/) He is the author or co-author of more than 300 scientific publications, became co-editor of the *Genomic and Precision Medicine* book series, and co-authored the textbook *Genetics in Medicine*.[2](https://www.nasonline.org/directory-entry/huntington-f-willard-82vkg4/)
In industry, he co-founded Athersys, Inc. in [Cleveland](https://www.edgepedia.org/cleveland) in 1995 and Athleticode, Inc. in San Francisco in 2009, served on the board of AptamiR Therapeutics from 2011 to 2014, and consulted for [Third Rock Ventures](https://www.edgepedia.org/third-rock-ventures) in 2014-2015.[1](https://www.geisinger.org/-/media/onegeisinger/pdfs/ghs/research/find-an-investigator/huntington-f-willard-cv-mar-2018) His CV lists three US patents naming him as an inventor: two (1997 and 1999) for methods of stably cloning large repeating DNA sequences, and one (2002) for an artificial mammalian chromosome.[1](https://www.geisinger.org/-/media/onegeisinger/pdfs/ghs/research/find-an-investigator/huntington-f-willard-cv-mar-2018)
## XIST-based silencing since 2023
XIST's ability to silence an entire chromosome has become the basis for proposed therapies for trisomy 21 ([Down syndrome](https://www.edgepedia.org/down-syndrome)). A 2024 review in *Human Genetics* notes that expression of an XIST transgene inserted into one chromosome 21 can comprehensively silence that chromosome in vitro and dosage-compensate trisomy 21, and that rare case studies of imbalanced X;autosome translocations indicate natural XIST can rescue an otherwise lethal trisomy.[13](https://pmc.ncbi.nlm.nih.gov/articles/PMC11294271/) A 2025 *PNAS* study reported a modified CRISPR/Cas9 method, using a Cas9-exonuclease fusion and SNP-specific guide RNAs to target one chromosome 21 copy, that raised integration efficiency of the 14 kb XIST gene into an extra chromosome 21 to 20-40%, with RNA sequencing showing partial transcriptional correction of the trisomic gene dosage.[14](https://www.pnas.org/doi/abs/10.1073/pnas.2517953123) Also in 2025, a study in *Stem Cell Research & Therapy* reported that transient dual inhibition of TP53 and [DNA methylation](https://www.edgepedia.org/dna-methylation) during Cas9 editing raised the proportion of XIST-positive female human pluripotent stem cells from about 5% to about 43.7%.[15](https://doi.org/10.1186/s13287-025-04501-4)
## References
1. [Curriculum Vitae, Huntington Faxon Willard, Ph.D. (Geisinger)](https://www.geisinger.org/-/media/onegeisinger/pdfs/ghs/research/find-an-investigator/huntington-f-willard-cv-mar-2018)
2. [Huntington F. Willard, NAS Member Directory](https://www.nasonline.org/directory-entry/huntington-f-willard-82vkg4/)
3. https://www.cell.com/ajhg/fulltext/S0002-9297(10)00004-2
4. [A gene from the region of the human X inactivation centre is expressed exclusively from the inactive X chromosome (Nature, 1991)](https://www.nature.com/articles/349038a0)
5. https://www.cell.com/cell/fulltext/S0092-8674(00)80071-9
6. [Huntington Faxon Willard | American Academy of Arts and Sciences](https://www.amacad.org/person/huntington-faxon-willard)
7. [2009 William Allan Award Address: Life in The Sandbox (American Journal of Human Genetics)](https://doi.org/10.1016/j.ajhg.2010.01.037)
8. [Huntington Willard Named President and Director of Marine Biological Laboratory](https://www.mbl.edu/news/huntington-willard-named-president-and-director-marine-biological-laboratory)
9. [Artificial Chromosomes Coming to Life (Science, 2000)](https://doi.org/10.1126/science.290.5495.1308)
10. [Assembly and characterization of heterochromatin and euchromatin on human artificial chromosomes (Genome Biology, 2004)](https://genomebiology.biomedcentral.com/articles/10.1186/gb-2004-5-11-r89)
11. [Huntington F. Willard, PhD | HHMI Professor Profile](https://hhmi.org/scientists/huntington-f-willard)
12. [Huntington F. Willard to Step Down as Marine Biological Laboratory President](https://www.mbl.edu/news/huntington-f-willard-step-down-marine-biological-laboratory-president)
13. [Trisomy silencing by XIST: translational prospects and challenges (Human Genetics, 2024)](https://pmc.ncbi.nlm.nih.gov/articles/PMC11294271/)
14. [A modified CRISPR/Cas9 approach in silencing the triplication in Down syndrome (PNAS, 2025)](https://www.pnas.org/doi/abs/10.1073/pnas.2517953123)
15. [Highly efficient XIST reactivation in female hPSC (Stem Cell Research & Therapy, 2025)](https://doi.org/10.1186/s13287-025-04501-4)
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*Topic: Encyclopedia › Life and health › Life and health scientists › Life scientists › Researchers in genetics, genomics, and genome engineering › Epigenetics and chromatin biology*
*Initially written Sep 20, 2026 · Reviewed: Sep 25, 2026 · Edited: Sep 25, 2026; Oct 15, 2026 · Last review: Sep 25, 2026*
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