Dissertation Research: Molecular Variation in Two Circumpolar Sea Urchins

9423662 EANES范围广泛和分布广泛的生物的物种形成动力学继续对进化生物学家提出挑战，特别是在许多情况下地理隔离似乎不太可能的海洋无脊椎动物中。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起主要作用。特别是在海胆中，一种分子（蛋白质“结合蛋白”）已经被表征为介导物种特异性受精。现在，dna技术使我们能够研究这种繁殖障碍的进化背后的力量，并且可以很容易地在海胆身上研究其适应性的后果。自由产卵的棘球蚴和苍白棘球蚴是细胞和发育生物学中主要模式生物紫癜棘球蚴的近亲。它们共同出现在整个北部高纬度地区，并可能不对称杂交。本研究将在DNA水平上研究它们的种群结构及其结合分子的进化。初步数据显示了地理分化和有趣的分子进化模式。该项目还将增加关于环北极物种种群结构和动态的稀缺数据。这对越来越多地收获的葡萄球菌尤其重要。

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.