The evolution of germ-soma cellular differentiation represents a key step in the evolution of multicellular individuality. Volvox carteri and its relatives, the volvocine green algae, provide a model system for studying the evolution of cellular differentiation. In V. carteri, the regA gene controls somatic cell differentiation and is found in a group of paralogs called the reg cluster, along with rlsA, rlsB, and rlsC. However, the developmental program of V. carteri is derived compared to other volvocine algae. Here we examine Volvox powersii which possesses an ancestral developmental program and independent evolution of the Volvox body plan. We sequenced the reg cluster from V. powersii wild-type and a mutant with fewer cells and altered germ-soma ratio. We found that the mutant strain’s rlsB gene has a deletion predicted to cause a truncated protein product. We developed a genetic transformation procedure to insert wild-type rlsB into the mutant strain. Transformation did not result in phenotypic rescue, suggesting the rlsB mutation is insufficient for generating the mutant phenotype. The transformation techniques and sequences described here provide essential tools to study V. powersii, a species well suited for studying the evolution of cellular differentiation and convergent evolution of Volvox morphology.

生殖细胞分化的进化代表了多细胞个体进化的关键步骤。Volvox carteri及其近亲 volvocine 绿藻为研究细胞分化的进化提供了一个模型系统。在V. carteri中，regA基因控制体细胞分化，并与rlsA、rlsB和rlsC一起存在于称为reg簇的一组旁系同源物中。然而，与其他 volvocine 藻类相比， V. Carteri 的发育程序是派生的。在这里，我们检查了具有祖先发育程序和独立进化的Volvox powersii 。沃尔沃车身计划。我们对来自V. powersii野生型的reg簇和具有较少细胞和改变的生殖细胞比率的突变体进行了测序。我们发现突变菌株的rlsB基因有一个预计会导致截断蛋白质产物的缺失。我们开发了一种遗传转化程序，将野生型rlsB插入突变株中。转化没有导致表型拯救，表明rlsB突变不足以产生突变表型。这里描述的转化技术和序列为研究V. powersii提供了必要的工具, 一个非常适合研究细胞分化进化和团藻形态趋同进化的物种。