Hybridization of Darwin's Finches on the Galapagos Islands

9306753格兰特对杂交的研究在进化生物学中很重要，因为它揭示了物种形成最后阶段的作用力量。一些动物种群通常进行杂交，但要确定自然界中杂交的原因和后果通常是困难的，如果不是不可能的话。建议的研究利用了一个特别有利的情况来调查杂交的原因和杂交后代相对较高的适合度的原因。在加拉帕戈斯群岛的达芙内梅杰小岛上，中地雀Geospiza Fortis偶尔会与另外两只进行杂交；另一种是旅居种G.scobens，一种移民种G.fuliginosa。系谱分析表明，在几年的时间里，杂交种可能会存活下来，繁殖得与亲本物种一样好，甚至更好。它们高适合度的生态原因将通过对饲养效率和饮食的深入研究来调查。增强杂合性可能产生的优势将通过对东方棉和北美棉群体近亲交配效应的分析来评估。杂交的原因将通过对交配模式的统计分析来确定。%拟议研究的基本方面和应用方面。这些结果将对我们理解物种形成具有重要的理论意义。证明杂交在维持小种群和潜在濒危种群的遗传多样性方面的作用将是保护生物学应用领域的价值所在。

9306753 Grant The study of hybridization is important in evolutionary biology because it reveals the forces at work in the final stages of speciation. Some populations of animal species commonly hybridize, but it is usually difficult if not impossible tho determine the causes and consequences of hybridization in nature. The proposed research takes advantage of an exceptionally favorable situation for investigating the causes of hybridization and the reasons for relatively high fitness of the hybrids. On the small island of Daphne Major in the Galapagos archipelago the medium ground finch, Geospiza fortis, occasionally interbreeds with the two others; G.scandens, a resident species, G. fuliginosa, an immigrant. Pedigree analysis has shown that hybrids may survive and breed as well or better than the parental species, over several years. Ecological reasons for their high fitness will be investigated by intensive study of feeding efficiencies and diets. Possible advantages arising from enhanced heterozygosity will be assessed by an analysis of inbreeding effects in the G.fortis and G.scandens populations. Causes of interbreeding will be identified by statistical analysis of mating patterns. %%% There are basic and applied aspects of the proposed research. Results will be of theoretical importance to our understanding of speciation. A demonstration of the role of hybridization in maintaining genetic variation in small and potentially endangered populations will be the value to the applied field of conservation biology.