Development of the Genetic Map of Volvox

Kirk Volvox carteri是一个潜在的强大的模型系统，用于分析分化和发育的遗传学。它是一种真核多细胞生物，但它只包含两种细胞类型，即致命的体细胞和不朽的生殖细胞，它们以一种可预测的模式排列在一个简单的球体内。生物体通常是单倍体，繁殖通常是无性的，突变在表型上是明显的，但由于有性繁殖很容易诱导，正式的遗传分析是可能的。导致组织异常的突变是可行的，因为细胞发育是自主的。由于团藻的近亲缺乏细胞分化，因此存在进行进化研究的潜力。这种生物作为模式系统的一个限制是缺乏遗传图谱，也无法对其进行改造。后一种方法是最近在我们的实验室开发出来的，我们正在着手进行前一种方法。遗传图谱已被纳入许多限制性片段长度多态性（RFLP）和耐药标记。通过转座子诱变来标记和恢复感兴趣的基因的方法已经发展起来。未来五年的目标是标记、识别和绘制调节生殖细胞和体细胞的发育和分化以及形态发生运动、细胞衰老和程序性细胞死亡的基因。这个项目的目标的实现将为简单的单细胞生物和更复杂的多细胞生物之间的研究和理解发育、分化和进化提供一个桥梁。

9300047 Kirk Volvox carteri is a potentially powerful model system for analysis of the genetics of differentiation and development. It is a eukaryotic multicellular organism but it contains only two cell types, mortal somatic cells and immortal germ cells, which are arranged in a predictable pattern within a simple spheroid. The organism is normally haploid, reproduction is usually asexual and mutations are phenotypically obvious but because sexual reproduction is readily induced, formal genetic analysis is possible. Mutations which cause organizational abnormalities are viable because cell development is autonomous. Because there are close relatives of Volvox that lack cellular differentiation, the potential for evolutionary studies exists. One limitation of this organism as a model system has been the lack of a genetic map and an inability to transform it. The latter procedure has been recently developed in our laboratory and we are embarking upon the former. The genetic map has been expanded by the incorporation of many restriction-fragment-length-polymorphism (RFLP) and drug resistance markers. Methods for tagging and recovering genes of interest via transposon mutagenesis have been developed. The goals for the next five years are to tag, identify and map genes that regulate development and differentiation of germ and somatic cells as well as morphogenetic movements and cellular senescence and programmed cell death. %%% The achievement of the goals of this project will provide a bridge organism between simpler single cell organisms and much more complex multicellular organisms for the study and understanding of development and differentiation as well as evolution.