From chemical embryology to nucleosome patterning - an interview with Roumen G. Tsanev.

Roumen Tsanev was a prominent Bulgarian scientist whose pioneering ideas about the role for chromatin in cell differentiation and development led him to propose the first hypothesis for epigenetic information based on a histone code. To test experimentally his ideas, Dr.Tsanev explored nucleosome structure and heterogeneity and generated seminal data on nucleosome segregation in replicating chromatin. Roumen Tsanev made significant contributions to the understanding of chromatin changes that underlie zygotic gene activation. He identified sperm specific chromatin components tightly bound to DNA and demonstrated that the histone complement of the male pronucleus appears before the onset of DNA synthesis in the mouse zygote. In this interview, Roumen Tsanev talks about his passion for science and literature, reminisces about surmounting the harsh realities in post-war communist Bulgaria through creativity and determination, and explains what led him to propose that histones were carriers of epigenetic information. Dr. Tsanev discusses mathematical models of gene regulation and recalls computer simulations that reveal the non-linearity of genetic networks. He explains how this non-linearity could affect cell proliferation, differentiation, development and evolution.