RegA, RegA Homologs, and Control of Cellular Differentiation in Volvox Carteri

regA， regA同系物，以及在Volvox carters中的细胞分化控制植物和动物很久以前就从单细胞祖先进化而来。这个过程早期的关键一步是多细胞生物的发明。制造多种细胞类型的能力。但是因为植物和动物拥有如此多的细胞和细胞类型，而且因为它们已经进化了很长时间，所以很难在遗传水平上确定它们是如何变成多细胞的。也就是说，目前尚不清楚哪种类型的基因或基因的变化更有可能使一种单细胞生物产生拥有多种细胞类型的后代。这个项目试图用绿藻（多细胞的Volvox carteri和单细胞的Chlamydomonas reinhardtii）来回答这个问题，这些绿藻是植物的近亲，但更简单，更适合研究多细胞的进化。实验将集中在一个基因家族（regA和相关基因）上，该基因家族在团藻和衣藻中进化不同，并被认为控制着制造不同细胞类型的能力。为了确定在Volvox中多种细胞类型是如何产生的，以及在这种生物体中产生多种细胞类型的能力是如何进化的，将使用分子遗传学方法来识别由regA控制的基因，并比较regA相关基因在Volvox和Chlamydomonas中的作用。预计这些实验将显示基因如何随着时间的推移以相对微妙的方式发生变化，从而带来巨大的生物学变化。这些研究将大大提高对复杂生物如植物和动物如何进化的理解，并将提供一个容易教的例子，说明进化是如何在基因水平上产生新类型的细胞和有机体的。这个项目的一个重要的更广泛的影响是，两名具有长期和成功的学术研究潜力的少数民族女博士生将进行这项研究。他们将增加未被充分代表的群体在科学领域的代表性，他们的榜样和指导应该激励许多其他少数民族学生从事科学事业。

Stephen M. MillerProposal # IOS-0744719regA, regA homologs, and control of cellular differentiation in Volvox carteriPlants and animals evolved long ago from single-celled (unicellular) ancestors. A critical early step in this process was the invention of multicellularity?the ability to make more than one cell type. But because plants and animals possess so many cells and types of cells, and because they have been evolving for so long, it has been very difficult to determine at a genetic level just how they came to be multicellular. That is, it is unclear which types of genes or changes in genes might make it more likely for a species of single-celled organisms to make descendants that possess more than one cell type. This project seeks to answer this problem using species of green algae (multicellular Volvox carteri and unicellular Chlamydomonas reinhardtii) that are close relatives of plants but simpler and better suited to study the evolution of multicellularity. Experiments will focus on a family of genes (regA and related genes) that evolved differently in Volvox and Chlamydomonas and that are believed to control the ability to make different cell types. To determine how multiple cell types are made in Volvox and how the ability to make more than one type of cell evolved in this organism, molecular genetic methods will be used to identify genes that are controlled by regA, and to compare the actions of regA-related genes in Volvox and Chlamydomonas. It is expected that these experiments will show how genes can change in relatively subtle ways over time to bring about monumental biological change. These studies should greatly improve the understanding of how complex organisms like plants and animals evolved, and will provide an easily teachable example of how evolution works at the level of the gene to produce new types of cells and organisms. An important broader impact of this project is that two female minority Ph.D. students who have great potential for long and successful careers in academic research will carry it out. They will increase the representation of underrepresented groups in the sciences, and their example and guidance should inspire many other minority students to pursue careers in science.