Fossil-calibrated molecular clock data enable reconstruction of steps leading to differentiated multicellularity and anisogamy in the Volvocine algae.

Background: Throughout its nearly four-billion-year history, life has undergone evolutionary transitions in which simpler subunits have become integrated to form a more complex whole. Many of these transitions opened the door to innovations that resulted in increased biodiversity and/or organismal efficiency. The evolution of multicellularity from unicellular forms represents one such transition, one that paved the way for cellular differentiation, including differentiation of male and female gametes.

Phylotranscriptomics points to multiple independent origins of multicellularity and cellular differentiation in the volvocine algae.

Background: The volvocine algae, which include the single-celled species Chlamydomonas reinhardtii and the colonial species Volvox carteri, serve as a model in which to study the evolution of multicellularity and cellular differentiation. Studies reconstructing the history of this group have by and large relied on datasets of one to a few genes for phylogenetic inference and ancestral character state reconstruction. As a result, volvocine phylogenies lack concordance depending on the number and/or type of genes (i.

Cryopreservation of clonal and polyclonal populations of .

Long-term preservation of laboratory strains of has historically involved either liquid nitrogen cryopreservation, which is expensive and labor intensive, or storage on agar plates, which requires frequent transfer to new plates, and which may leave samples susceptible to contamination as well as genetic drift and/or selection. The emergence of as a model organism for genetic analysis and experimental evolution has produced an increasing demand for an efficient method to cryopreserve populations. The GeneArt™ Cryopreservation Kit for Algae provides the first method for algal storage at -80°C; however, little is known about how this method affects recovery of different clones, much less polyclonal populations.