Dissertation Research: Molecular Variation in Two Circumpolar Sea Urchins

9423662 Eanes广泛分布的生物中物种形成的动态继续挑战进化生物学家，特别是在海洋无脊椎动物中，因为在许多情况下，地理隔离似乎不太可能。最近的研究表明，精子和卵子的分子相互作用可能在将配子自由释放到水中的动物的生殖隔离中发挥重要作用。特别是在海胆中，一种分子(蛋白质“结合蛋白”)已被确定为调节物种特定受精的分子。DNA技术现在允许我们检查这种生殖障碍进化背后的力量，而且在海胆身上很容易研究对健康的影响。自由产卵的紫球藻和苍白球藻是一种重要的细胞和发育生物学模式生物--紫球藻的近亲。它们在北部高纬度地区共同出现，并可能不对称地混合。这项研究将在DNA水平上研究它们的种群结构和结合蛋白分子的进化。初步数据显示了地理分化和有趣的分子进化模式。该项目还将增加有关北极圈物种种群结构和动态的稀缺数据。这对正在被越来越多地收获的德罗巴赫乳杆菌来说尤其重要。

9423662 EANES The dynamics of speciation in wide-ranging and widely dispersing organisms continues to challenge evolutionary biologists, especially in marine invertebrates where geographic isolation seems unlikely in many cases. Recent work suggests that the molecular interaction of sperm and eggs may play a major role in reproductive isolation in animals that release gametes freely into the water. In sea urchins in particular, a molecule (the protein "bindin") has been characterized that mediates species specific fertilization. DNA-techniques now permit us to examine the forces that underlie the evolution of this reproductive barrier, and the consequences for fitness can be easily studied in sea urchins. The free spawning echinoids Strongylocentrotus droebachiensis and S. pallidus are close relatives of a major model organism in cellular and developmental biology, S. purpuratus. They co-occur throughout northern high latitudes and may hybridize asymmetrically. This study will examine their population structure and the evolution of their bindin-molecules at the DNA level. Preliminary data show geographic differentiation and interesting patterns of molecular evolution. The project will also add to the scarce data on the population structure and dynamics of circumarctic species. This is particularly important for S. droebachiensis which is being harvested increasingly.