Ramin Yadegari, PhD, is interested in understanding the gene-regulatory processes that mediate fertilization and initiation of seed development. The plant life cycle alternates between a diploid sporophyte generation and a haploid gametophyte generation. The angiosperm female gametophyte is critical to the reproductive process. It is the structure within which egg cell production and fertilization take place. Using the model plant Arabidopsis thaliana, Dr. Yadegari and his lab are focusing on two specific processes: 1) development of the female gametophyte and 2) control of seed initiation by gene-regulatory complexes before and after fertilization. For example, they use a combination of expression-based analyses and genetic resources of Arabidopsis to identify major gene-regulatory networks involved in differentiation of the female gametophyte cell types. Similarly, using biochemical, molecular and genetic approaches, they identify components of the Polycomb-group complexes that mediate epigenetic repression of gene expression before fertilization.