Evolution of the VARL Gene Family
The evolution of germ-soma differentiation is a critical component of the evolutionary transition in individuality from unicellularity to multicellularity. Somatic cells lose their reproductive capacity and germ cells have a decreased ability to survive independently. Thus, germ and somatic cells must operate in concert to survive and produce the next generation. In Volvox carteri, the development of somatic cells is controlled by regA, a transcription factor that regulates chloroplast biogenesis. regA is a member of the VARL gene family and part of a tandem duplication of four to five genes known as the regA gene cluster. Our lab identified when regA and the regA gene cluster evolved in the Volvocine green algae and showed that it is present in species with and without obligate somatic cells (Hanschen et al. 2014; Grochau-Wright et al. 2017). Future research will focus on the function of regA in species that lack obligate somatic cells.