To Whom It May Concern:

It is my great pleasure to write this letter in support of Dr. Guo-Cheng Yuan’s application to a faculty position in your department. I got to know Guo-Cheng about a year ago while he was a postdoctoral fellow under the supervision of Steve Altschuler, who was at the time a fellow of the Harvard Center of Genomic Researches (CGR). Since the departure of Steve, I have been Guo-Cheng’s postdoctoral mentor. I am glad to comment on his scientific and personal qualities, with the knowledge that his teaching qualities will be commented by other people.

Guo-Cheng is a gifted and hard-working scientist who is passionate about his work. He obtained his Ph.D degree in a highly ranked program in mathematics (U of Maryland) and had extensive postdoctoral research experience in analyzing complex dynamical systems, such as the ocean dynamics. Through these trainings he has built a solid foundation, which allows him to quickly master new techniques. Before he came to Harvard, Guo-Cheng had no formal training in biology. But he was eager, and also very effective, to learn biology by sitting in biological classes and by intensively reading the literature. As a result, Guo-Cheng now belongs to a very small group of people equipped with both strong analytical skills and broad biological knowledge. Guo-Cheng is never satisfied with knowing the basic facts but insists on a thorough understanding of their connections. As evidence of his extraordinary capability and working ethic, Guo-Cheng was made the first author of a paper published in Science only after one year into his biology venture.

Guo-Cheng’s research has been focused on dissecting the structure and investigating the regulatory roles of chromatin. Chromatin plays important roles in many fundamental biological processes. However, most experimental studies have been limited to isolated genomic regions. Recent advances in the microarray technology have begun to generate new evidence for understanding the regulatory mechanisms at a genomic-scale. However, although it is clear that many experimental studies are required in order to discover new functions of the chromatin, the power of systematic exploration of the connections among existing data has not been sufficiently appreciated in the chromatin community. Guo-Cheng’s background is uniquely suitable for filling this void.

Recently, Guo-Cheng and I have been collaborating on a project that investigates the global regulatory role of histone acetylation. We used advanced statistical techniques, some of which he had not encountered in the past. But Guo-Cheng learned these techniques very quickly. Furthermore, he was not satisfied with simply presenting the statistical results but aspired to look for the most compatible biological interpretation of the results. In order to do that he set out to read many biological papers and came back with a creative hypothesis that was consistent both with existing biological knowledge and statistical analysis. Since the prevailing approach of investigating biological networks is largely based on sequence and mRNA expression data only, this work to elucidate the regulatory role of chromatin will probably have an impact on identifying new, more efficient computational approaches to the investigation of regulatory network in biological systems. This collaboration also gave me a great opportunity to observe Guo-Cheng’s distinguished scientific qualities. I am completely satisfied with his persistent and hard-working nature, and am very impressed by the maturity embodied in someone who has just transited into a new career.

Guo-Cheng, or “GC”, as many of the people here would like to call him fondly, is a very pleasant person to work with. He is kind, polite, and considerate to other people. He is always willing and ready to help others in the lab with any difficulty they may encounter. In summary, I believe that Guo-Cheng will grow to become a distinguished researcher and will also be a wonderful colleague to have. I am happy for him to move on to the next level of his scientific career. I support his application without any reservation. Please feel free to contact me should you require any further elaboration.

Best wishes,

Jun Liu

Professor

JL/ms