Ross C. Hardison

About Me

I grew up in middle Tennessee, graduating from Columbia Central High School in 1969. I attended Vanderbilt University, receiving a B.A. degree in Chemistry in 1973, followed by graduate work in the Department of Biochemistry at the University of Iowa in the laboratory of Roger Chalkley. After receiving my Ph.D. in 1977, I did post-doctoral work with Tom Maniatis at the California Institute of Technology. In 1980, I joined the faculty of the Department of Biochemistry and Molecular Biology (at least the third name for the department in my time here) of the Pennsylvania State University. I have benefitted from three Sabbaticals, one at the Biomedical Research Centre at the University of British Columbia with John Schrader (1988), another at the Fred Hutchinson Cancer Research Center with Mark Groudine (1999-2000), and one spent working with the various laboratories in our VISION consortium studying epigenomics and gene regulation in blood cells (2018).

While at Penn State, I helped found the Center for Eukaryotic Gene Regulation and served as its director in the mid-1990s, and I was one of the founders and director of the Center for Comparative Genomics and Bioinformatics from 2003-2016. Since 2016, I have served as the Associate Director for the Genome Sciences Institute of the Huck Institutes of Life Sciences. 

Department or University Committees

• BMB: Faculty Recruiting
  
   
• Graduate Student Recruiting
  
   
• Faculty Development
  
   
• Teaching and Research Professor Faculty Affairs

Program or Department Affiliations

Editorial Boards

Centers

Research Interest

Genomics and gene regulation

Research Summary

The long-term goal of my research is to understand molecular mechanisms and evolution of gene regulation in mammals. I began studying fundamental aspects of chromatin structure as a graduate student, and then moved on to developing methods for isolating genes as molecular clones of genomic DNA as a post-doc with Tom Maniatis. Those early molecular cloning experiments established the technologies and approaches that we now know as genomics. In my lab at Penn State, we built from those initial clones to define the structures and developmental expression of hemoglobin gene clusters in mammals. This work expanded into decades of collaborative research with Webb Miller to rigorously align genomic DNA sequences between species and to use those alignments to illuminate genome evolution and predict gene regulatory regions. Webb and I established a paradigm of molecular biologists and computational scientists working together to define important problems with bioinformatic solutions, developing algorithms that give informative solutions and scale to whole-genome approaches, and experimentally testing hypotheses derived from the bioinformatic analysis to infer the biological meaning of the bioinformatic results. The whole-genome interspecies alignments of genomic DNA developed during this phase are still the backbone for many comparative genomics studies. 

For the past 15 years, our research has expanded from genomic sequence alignments to the epigenomes of differentiating mouse and human blood cells. Epigenetic features are biochemical modifications and molecules that lie “on top of” (epi-) the genetic material, DNA, including histone modifications in chromatin, transcription factor binding to chromatin, RNA from coding and noncoding genes, and nuclease accessible regions indicative of remodeled nucleosomes around gene regulatory regions. We employ state-of-the art, high-throughput, sequencing-based assays, such as ChIP-seq, RNA-seq, ATAC-seq, and Hi-C to construct widely used maps of the epigenomic and transcriptomic landscapes across the genomes of mammalian blood cells. Thus, research in my laboratory is well-grounded in the basic biochemistry and molecular biology of genomes, epigenomes, and gene expression. We also continue to work with our statistical and computational collaborators to integrate the rich and diverse epigenomic datasets to provide simple, easily interpretable views of the regulatory landscape and how it changes across cell types and conditions. We also use the integrated epigenomic data as input into various machine-learning approaches to identify candidate regulatory elements, such as promoters and enhancers, follow their changes in epigenetic state across differentiation, and estimate the regulatory output from each on the candidate target genes (see Figure). 

This diversity of projects has been enabled by excellent workers in my lab and by long-term collaborations with other researchers, including Webb Miller, Yu Zhang, Qunhua Li, and Shaun Mahony at Penn State, James Taylor at Johns Hopkins, David Bodine at NIH, Mitch Weiss at St. Jude Children’s Research Hospital, Gerd Blobel at the Children’s Hospital of Philadelphia, and Barbara Wold at the California Institute of Technology. I was a member of the ENCODE Project Consortium from its inception through Phase 3, with my own laboratory producing 133 datasets of transcription factor occupancy, histone modifications, nuclease sensitivity, and transcriptomes. Currently I work with an international group of collaborators (including Berthold Göttgens at Cambridge University and Doug Higgs at Oxford University in addition to collaborators already mentioned) to develop and test integrative models to provide ValIdated Systematic IntegratiON (VISION project) of the regulatory landscape, chromatin conformation, and transcriptomes of human and mouse hematopoietic cells. These integrative models, supported by extensive experimental tests, open the door for a new phase of molecular genetics. This new phase, driven by comprehensive genomic and epigenomic data, should lead to more complete understanding and enable translation to applications in medicine and other fields. 

Efforts such as ours to comprehensively map and validate regulatory elements are having a substantial impact on medical science. Aberrant expression of genes has been implicated both in rare inherited diseases as well as in common, complex diseases. Indeed, most of the trait-associated genetic variants discovered by genome wide association studies in humans are in non-coding regions of the genome, and they are highly enriched in DNA segments with epigenetic signatures of regulatory elements. Research such as ours provides reliable maps of regulatory elements, which can then be used to develop strong hypotheses about the mechanisms by which genetic variants impact complex phenotypes including many diseases. Regulatory elements discovered by approaches such as those described here are now being targeted in clinical trials of therapeutic genome editing approaches for sickle cell disease, thalassemias, and other diseases. Now is truly an exciting time in functional genomics!

Figure legend, Hardison lab

Figure legend. A view of the epigenomic landscape, candidate regulatory regions, and their output toward regulation of the Alas2 gene in mouse erythroid cells, as of late 2019. The Alas2 gene encodes the enzyme catalyzing the rate-limiting step of heme biosynthesis, and it is strongly up-regulated during erythropoiesis. In a 250kb region centered on Alas2 but containing several other genes (central track) within the same topologically associated domain (bottom tracks), we show colorful maps of the epigenetic states determined by the Integrative and Discriminative Epigenome Annotation System, or IDEAS, underneath the gene models. Each color represents an epigenetic state, which is a commonly occurring combination of histone modifications and other epigenetic features, with brighter, warmer colors denoting states associated with gene activation and green marking transcribed regions. The state maps are shown for a series of cells differentiating from a common myeloid progenitor cell population (CMP) to maturing erythroblasts (ERY). Note that the Alas2 gene shows a stronger epigenetic pattern for activation and transcription as the cells undergo erythroid differentiation, in concert with its strongly increased expression. The candidate cis-regulatory elements (cCREs) identified by our systematic epigenetic analyses are shown as bright red rectangles. An initial estimate of their regulatory output based on their changes in epigenetic states across cell types was computed as an epigenetic regulatory potential, or eRP score, shown as blue rectangles and numbers. Three of these cCREs shown in our earlier work to be active as a promoter (Alas2pr) or enhancers (Alas2R1 and Alas2R3), along with a negative control (Alas2NC1), shown as bright pink rectangles. The predicted eRP scores fit remarkably well with those experimental results. Furthermore, several other, more distal cCREs have high predicted eRP scores. We are currently using CRISPR-cas9 approaches to systematically mutate these cCREs in erythroid cell line models to see if the mutations cause the predicted changes in gene expression.

Teaching and Mentoring

I have taught a wide variety of courses at Penn State at both the graduate and undergraduate levels. Currently, much of my teaching is in genomics, especially in the use of high-throughput, comprehensive approaches to infer or predict functional elements in genomes, followed by experimentally tests of those predicted functions. I teach a graduate level, on-line Genomics course that is offered by our department through the World Campus of Penn State.

Honors and Awards

• Sigma Xi Public Research Lecture Award, University of Iowa, 1976
  
   
• C. P. Berg Award, Department of Biochemistry, University of Iowa, 1978
  
   
• Jane Coffin Childs Memorial Fund for Medical Research, Postdoctoral Fellow, California Institute  of Technology 1977-1979
  
   
• NIH Postdoctoral Fellowship, California Institute of Technology 1979-1980
  
   
• NIH Research Career Development Award, Pennsylvania State University, 1987-1992 
  
   
• Visiting Scholar, Marshall University School of Medicine, March 24, 1997
  
   
• Award in the Special Recognition Program for Collaborative Instructional and Curricular Innovation, for BIOL/BMB497E "Genetic Analysis", Penn State University, 1998-1999.
  
   
• Faculty Scholar Award for Outstanding Achievement, jointly with Dr. Webb Miller, Penn State University, 2000
  
   
• T. Ming Chu Professor of Biochemistry and Molecular Biology, The Pennsylvania State University, 2005 - present
  
   
• Member, National Advisory Council, National Human Genome Research Institute, National Institutes of Health, 2011-2013.
  
   
• External Scientific Panel, GTEx Genotype Tissue Expression Project, NIH Common Fund, 2010-2016.
  
   
• Scientific Advisory Board (chair), GENCODE project (human and mouse gene annotation), Sanger Centre and EBI, 2014-2020.
  
   
• Scientific Advisory Board, University of California at Santa Cruz Genome Browser, 2014-2020.
  
   
• External Evaluation Committee, NIDDK Cooperative Centers of Excellence in Hematology, 2018.

Selected Publications

The following are 40 publications representing all stages of my research career, from graduate school to the present – a span of almost a half century! This list can be viewed at NCBI, with links to publications, at https://www.ncbi.nlm.nih.gov/sites/myncbi/ross.hardison.1/collections/59107996/public/ 

A complete list of my publications can be viewed from Google Scholar https://scholar.google.com/citations?user=waPNWUYAAAAJ&hl=en

Google Scholar lists almost all my publications (over 240) in a curated list. As of late 2019, it reports 55,453 citations to publications I have authored or co-authored, with an h-index of 79 and an i10-index of 198. Twelve of the papers have been cited over 1000 times.

• Guanjue Xiang, Cheryl A. Keller, Elisabeth Heuston, Belinda M. Giardine, Lin An, Alexander Q. Wixom, Amber Miller, April Cockburn, Jens Lichtenberg, Berthold Göttgens, Qunhua Li, David Bodine, Shaun Mahony, James Taylor, Gerd A. Blobel, Mitchell J. Weiss, Yong Cheng, Feng Yue, Jim Hughes, Douglas R. Higgs, Yu Zhang, Ross C. Hardison. An integrative view of the regulatory and transcriptional landscapes in mouse hematopoiesis. Genome Research. 2020 (anticipated) Under revision after positive review. bioRxiv doi: https://doi.org/10.1101/731729
  
   
• Zhang H, Emerson DJ, Gilgenast TG, Titus KR, Lan Y, Huang P, Zhang D, Wang H, Keller CA, Giardine B, Hardison RC, Phillips-Cremins JE, Blobel GA. Chromatin structure dynamics during the mitosis-to-G1 phase transition. Nature. 2019 Nov 27. doi: 10.1038/s41586-019-1778-y. PubMed PMID: 31776509
  
   
• Hardison RC, Zhang Y, Keller CA, Xiang G, Heuston EF, An L, Lichtenberg J, Giardine BM, Bodine D, Mahony S, Li Q, Yue F, Weiss MJ, Blobel GA, Taylor J, Hughes J, Higgs DR, Göttgens B. Systematic integration of GATA transcription factors and epigenomes via IDEAS paints the regulatory landscape of hematopoietic cells. IUBMB Life. 2019 Nov 25. doi: 10.1002/iub.2195. PubMed PMID: 31769130
  
   
• Heuston EF, Keller CA, Lichtenberg J, Giardine B, Anderson SM; NIH Intramural Sequencing Center., Hardison RC, Bodine DM. Establishment of regulatory elements  during erythro-megakaryopoiesis identifies hematopoietic lineage-commitment points. Epigenetics Chromatin. 2018 May 28;11(1):22. doi:10.1186/s13072-018-0195-z. PubMed PMID: 29807547, PMCID: PMC5971425
  
   
• Zhang Y, Hardison RC. Accurate and reproducible functional maps in 127 human cell types via 2D genome segmentation. Nucleic Acids Res. 2017 Sep 29;45(17):9823-9836. doi: 10.1093/nar/gkx659. PubMed PMID: 28973456, PMCID: PMC5622376
  
   
• Huang P, Keller CA, Giardine B, Grevet JD, Davies JOJ, Hughes JR, Kurita R, Nakamura Y, Hardison RC, Blobel GA. Comparative analysis of three-dimensional chromosomal architecture identifies a novel fetal hemoglobin regulatory element.  Genes Dev. 2017 Aug 15;31(16):1704-1713. doi: 10.1101/gad.303461.117. Epub 2017 Sep 15. PubMed PMID: 28916711, PMCID: PMC5647940
  
   
• Philipsen S, Hardison RC. Evolution of hemoglobin loci and their regulatory elements. Blood Cells Mol Dis. 2018 May;70:2-12. doi: 10.1016/j.bcmd.2017.08.001. Epub 2017 Aug 9. Review. PubMed PMID: 28811072, PMCID: PMC5807248
  
   
• Traxler EA, Yao Y, Wang YD, Woodard KJ, Kurita R, Nakamura Y, Hughes JR, Hardison RC, Blobel GA, Li C, Weiss MJ. A genome-editing strategy to treat β-hemoglobinopathies that recapitulates a mutation associated with a benign genetic condition. Nat Med. 2016 Sep;22(9):987-90. doi: 10.1038/nm.4170. Epub 2016 Aug 15. PubMed PMID: 27525524, PMCID: PMC5706766
  
   
• Zhang Y, An L, Yue F, Hardison RC. Jointly characterizing epigenetic dynamics across multiple human cell types. Nucleic Acids Res. 2016 Aug 19;44(14):6721-31.  doi: 10.1093/nar/gkw278. Epub 2016 Apr 19. PubMed PMID: 27095202, PMCID: PMC5772166
  
   
• Han GC, Vinayachandran V, Bataille AR, Park B, Chan-Salis KY, Keller CA, Long M,  Mahony S, Hardison RC, Pugh BF. Genome-Wide Organization of GATA1 and TAL1 Determined at High Resolution. Mol Cell Biol. 2015 Oct 26;36(1):157-72. doi: 10.1128/MCB.00806-15. Print 2016 Jan 1. PubMed PMID: 26503782, PMCID:  PMC4702602
  
   
• Dogan N, Wu W, Morrissey CS, Chen KB, Stonestrom A, Long M, Keller CA, Cheng Y, Jain D, Visel A, Pennacchio LA, Weiss MJ, Blobel GA, Hardison RC. Occupancy by key transcription factors is a more accurate predictor of enhancer activity than  histone modifications or chromatin accessibility. Epigenetics Chromatin. 2015 Apr 23;8:16. doi: 10.1186/s13072-015-0009-5. PubMed PMID: 25984238, PMCID: PMC4432502
  
   
• Byrska-Bishop M, VanDorn D, Campbell AE, Betensky M, Arca PR, Yao Y, Gadue P, Costa FF, Nemiroff RL, Blobel GA, French DL, Hardison RC, Weiss MJ, Chou ST. Pluripotent stem cells reveal erythroid-specific activities of the GATA1 N-terminus. J Clin Invest. 2015 Mar 2;125(3):993-1005. doi: 10.1172/JCI75714. Epub 2015 Jan 26. PubMed PMID: 25621499, PMCID: PMC4362246
  
   
• Yue F, Cheng Y, Breschi A, Vierstra J, Wu W, Ryba T, Sandstrom R, Ma Z, Davis C,  Pope BD, Shen Y, Pervouchine DD, Djebali S, Thurman RE, Kaul R, Rynes E, Kirilusha A, Marinov GK, Williams BA, Trout D, Amrhein H, Fisher-Aylor K, et al.  A comparative encyclopedia of DNA elements in the mouse genome. Nature. 2014 Nov  20;515(7527):355-64. doi: 10.1038/nature13992. PubMed PMID: 25409824,  PMCID: PMC4266106
  
   
• Cheng Y, Ma Z, Kim BH, Wu W, Cayting P, Boyle AP, Sundaram V, Xing X, Dogan N, Li J, Euskirchen G, Lin S, Lin Y, Visel A, Kawli T, Yang X, Patacsil D, Keller CA, Giardine B; mouse ENCODE Consortium., Kundaje A, Wang T, et al. Principles of regulatory information conservation between mouse and human. Nature. 2014 Nov 20;515(7527):371-375. doi: 10.1038/nature13985. PubMed PMID: 25409826, PMCID: PMC4343047
  
   
• Wu W, Morrissey CS, Keller CA, Mishra T, Pimkin M, Blobel GA, Weiss MJ, Hardison  RC. Dynamic shifts in occupancy by TAL1 are guided by GATA factors and drive large-scale reprogramming of gene expression during hematopoiesis. Genome Res. 2014 Dec;24(12):1945-62. doi: 10.1101/gr.164830.113. PubMed PMID: 25319994, PMCID: PMC4248312
  
   
• Pimkin M, Kossenkov AV, Mishra T, Morrissey CS, Wu W, Keller CA, Blobel GA, Lee D, Beer MA, Hardison RC, Weiss MJ. Divergent functions of hematopoietic transcription factors in lineage priming and differentiation during erythro-megakaryopoiesis. Genome Res. 2014 Dec;24(12):1932-44. doi: 10.1101/gr.164178.113. PubMed PMID: 25319996, PMCID: PMC4248311
  
   
• Kellis M, Wold B, Snyder MP, Bernstein BE, Kundaje A, Marinov GK, Ward LD, Birney E, Crawford GE, Dekker J, Dunham I, Elnitski LL, Farnham PJ, Feingold EA, Gerstein M, Giddings MC, Gilbert DM, Gingeras TR, Green ED, Guigo R, Hubbard T, Kent J, et al. Defining functional DNA elements in the human genome. Proc Natl Acad Sci U S A. 2014 Apr 29;111(17):6131-8. doi: 10.1073/pnas.1318948111. Epub 2014 Apr 21. Review. PubMed PMID: 24753594, PMCID: PMC4035993
  
   
• ENCODE Project Consortium. An integrated encyclopedia of DNA elements in the human genome. Nature. 2012 Sep 6;489(7414):57-74. doi: 10.1038/nature11247. PubMed PMID: 22955616, PMCID: PMC3439153
  
   
• Hardison RC, Taylor J. Genomic approaches towards finding cis-regulatory modules  in animals. Nat Rev Genet. 2012 Jun 18;13(7):469-83. doi: 10.1038/nrg3242. Review. PubMed PMID: 22705667, PMCID: PMC3541939
  
   
• Wu W, Cheng Y, Keller CA, Ernst J, Kumar SA, Mishra T, Morrissey C, Dorman CM, Chen KB, Drautz D, Giardine B, Shibata Y, Song L, Pimkin M, Crawford GE, Furey TS, Kellis M, Miller W, Taylor J, Schuster SC, Zhang Y, Chiaromonte F, et al. Dynamics of the epigenetic landscape during erythroid differentiation after GATA1 restoration. Genome Res. 2011 Oct;21(10):1659-71. doi: 10.1101/gr.125088.111. Epub 2011 Jul 27. PubMed PMID: 21795386, PMCID: PMC3202283
  
   
• Cheng Y, Wu W, Kumar SA, Yu D, Deng W, Tripic T, King DC, Chen KB, Zhang Y, Drautz D, Giardine B, Schuster SC, Miller W, Chiaromonte F, Zhang Y, Blobel GA, Weiss MJ, Hardison RC. Erythroid GATA1 function revealed by genome-wide analysis  of transcription factor occupancy, histone modifications, and mRNA expression. Genome Res. 2009 Dec;19(12):2172-84. doi: 10.1101/gr.098921.109. Epub 2009 Nov 3. PubMed PMID: 19887574, PMCID: PMC2792182
  
   
• Zhang Y, Wu W, Cheng Y, King DC, Harris RS, Taylor J, Chiaromonte F, Hardison RC. Primary sequence and epigenetic determinants of in vivo occupancy of genomic DNA  by GATA1. Nucleic Acids Res. 2009 Nov;37(21):7024-38. doi: 10.1093/nar/gkp747. PubMed PMID: 19767611, PMCID: PMC2790884
  
   
• Cheng Y, King DC, Dore LC, Zhang X, Zhou Y, Zhang Y, Dorman C, Abebe D, Kumar SA, Chiaromonte F, Miller W, Green RD, Weiss MJ, Hardison RC. Transcriptional enhancement by GATA1-occupied DNA segments is strongly associated with evolutionary constraint on the binding site motif. Genome Res. 2008 Dec;18(12):1896-905. doi: 10.1101/gr.083089.108. Epub 2008 Sep 25. PubMed PMID: 18818370, PMCID: PMC2593580
  
   
• Taylor J, Tyekucheva S, King DC, Hardison RC, Miller W, Chiaromonte F. ESPERR: learning strong and weak signals in genomic sequence alignments to identify functional elements. Genome Res. 2006 Dec;16(12):1596-604. Epub 2006 Oct 19. PubMed PMID: 17053093, PMCID: PMC1665643
  
   
• Wang H, Zhang Y, Cheng Y, Zhou Y, King DC, Taylor J, Chiaromonte F, Kasturi J, Petrykowska H, Gibb B, Dorman C, Miller W, Dore LC, Welch J, Weiss MJ, Hardison RC. Experimental validation of predicted mammalian erythroid cis-regulatory modules. Genome Res. 2006 Dec;16(12):1480-92. Epub 2006 Oct 12. PubMed [citation] PMID: 17038566, PMCID: PMC1665632
  
   
• Giardine B, Riemer C, Hardison RC, Burhans R, Elnitski L, Shah P, Zhang Y, Blankenberg D, Albert I, Taylor J, Miller W, Kent WJ, Nekrutenko A. Galaxy: a platform for interactive large-scale genome analysis. Genome Res. 2005 Oct;15(10):1451-5. Epub 2005 Sep 16. PubMed PMID: 16169926, PMCID: PMC1240089
  
   
• Welch JJ, Watts JA, Vakoc CR, Yao Y, Wang H, Hardison RC, Blobel GA, Chodosh LA,  Weiss MJ. Global regulation of erythroid gene expression by transcription factor  GATA-1. Blood. 2004 Nov 15;104(10):3136-47. Epub 2004 Aug 5. PubMed [citation] PMID: 15297311
  
   
• Hardison RC, Roskin KM, Yang S, Diekhans M, Kent WJ, Weber R, Elnitski L, Li J, O'Connor M, Kolbe D, Schwartz S, Furey TS, Whelan S, Goldman N, Smit A, Miller W, Chiaromonte F, Haussler D. Covariation in frequencies of substitution, deletion,  transposition, and recombination during eutherian evolution. Genome Res. 2003 Jan;13(1):13-26. PubMed PMID: 12529302, PMCID: PMC430971
  
   
• Elnitski L, Hardison RC, Li J, Yang S, Kolbe D, Eswara P, O'Connor MJ, Schwartz S, Miller W, Chiaromonte F. Distinguishing regulatory DNA from neutral sites. Genome Res. 2003 Jan;13(1):64-72. PubMed PMID: 12529307, PMCID: PMC430974
  
   
• Schwartz S, Kent WJ, Smit A, Zhang Z, Baertsch R, Hardison RC, Haussler D, Miller W. Human-mouse alignments with BLASTZ. Genome Res. 2003 Jan;13(1):103-7. Erratum  in: Genome Res. 2004 Apr;14(4):786. PubMed PMID: 12529312, PMCID: PMC430961
  
   
• Mouse Genome Sequencing Consortium., Waterston RH, Lindblad-Toh K, Birney E, Rogers J, Abril JF, Agarwal P, Agarwala R, Ainscough R, Alexandersson M, An P, Antonarakis SE, Attwood J, Baertsch R, Bailey J, Barlow K, Beck S, Berry E, Birren B, Bloom T, Bork P, Botcherby M, et al. Initial sequencing and comparative analysis of the mouse genome. Nature. 2002 Dec 5;420(6915):520-62. PubMed PMID: 12466850
  
   
• Hardison RC, Chui DH, Giardine B, Riemer C, Patrinos GP, Anagnou N, Miller W, Wajcman H. HbVar: A relational database of human hemoglobin variants and thalassemia mutations at the globin gene server. Hum Mutat. 2002 Mar;19(3):225-33. PubMed PMID: 11857738
  
   
• Hardison RC. Conserved noncoding sequences are reliable guides to regulatory elements. Trends Genet. 2000 Sep;16(9):369-72. PubMed PMID: 10973062
  
   
• Elnitski L, Miller W, Hardison R. Conserved E boxes function as part of the enhancer in hypersensitive site 2 of the beta-globin locus control region. Role of basic helix-loop-helix proteins. J Biol Chem. 1997 Jan 3;272(1):369-78. PubMed PMID: 8995271
  
   
• Huang XQ, Hardison RC, Miller W. A space-efficient algorithm for local similarities. Comput Appl Biosci. 1990 Oct;6(4):373-81. PubMed PMID: 2257499
  
   
• Margot JB, Demers GW, Hardison RC. Complete nucleotide sequence of the rabbit beta-like globin gene cluster. Analysis of intergenic sequences and comparison with the human beta-like globin gene cluster. J Mol Biol. 1989 Jan 5;205(1):15-40. PubMed PMID: 2486295
  
   
• Cheng JF, Raid L, Hardison RC. Isolation and nucleotide sequence of the rabbit globin gene cluster psi zeta-alpha 1-psi alpha. Absence of a pair of alpha-globin genes evolving in concert. J Biol Chem. 1986 Jan 15;261(2):839-48. PubMed PMID: 3001084
  
   
• Hardison RC. Comparison of the beta-like globin gene families of rabbits and humans indicates that the gene cluster 5'-epsilon-gamma-delta-beta-3' predates the mammalian radiation. Mol Biol Evol. 1984 Sep;1(5):390-410. PubMed  PMID: 6599973
  
   
• Maniatis T, Hardison RC, Lacy E, Lauer J, O'Connell C, Quon D, Sim GK, Efstratiadis A. The isolation of structural genes from libraries of eucaryotic DNA. Cell. 1978 Oct;15(2):687-701. PubMed PMID: 719759
  
   
• Hardison RC, Zeitler DP, Murphy JM, Chalkley R. Histone neighbors in nuclei and extended chromatin. Cell. 1977 Oct;12(2):417-27. PubMed PMID: 912751