新物種是怎么形成的,？這個問題是演化生物學(xué)中一個人們不斷研究的問題,。生殖分離會怎樣通過根據(jù)一個簡單的,、由生態(tài)環(huán)境決定的特征（在本研究案例中為棘魚的身體大?。┧龅淖匀贿x擇來演化,？關(guān)于這個問題的一個明確的實例，為生態(tài)環(huán)境在物種形成中所起的作用提供了一個新的例子,。實驗所用的魚來自不同的洲和不同的海洋,，把它們一起放進(jìn)位于美國威斯康星州Whitewater或加拿大溫哥華的實驗池中。決定這些獨立演化的魚類種群間的交配匹配性的因素是身體大小,。所以,，物種形成似乎基本上可作為基于少量性狀所做的選擇的一種副產(chǎn)品出現(xiàn)。
Nature 429, 294 - 298 (20 May 2004); doi:10.1038/nature02556
Evidence for ecology's role in speciation
JEFFREY S. MCKINNON1, SEIICHI MORI2, BENJAMIN K. BLACKMAN3,*, LIOR DAVID3,*, DAVID M. KINGSLEY3, LEIA JAMIESON1, JENNIFER CHOU1 & DOLPH SCHLUTER4
1 Biological Sciences, University of Wisconsin-Whitewater, Whitewater, Wisconsin 53190, USA
2 Biological Laboratory, Gifu-Keizai University, Ogaki, Gifu prefecture 503-8550, Japan
3 HHMI and Stanford University School of Medicine, Beckman Center B300, 279 Campus Drive, Stanford, California 94305-5329, USA
4 Department of Zoology and Centre for Biodiversity, University of British Columbia, Vancouver, BC V6T 1Z4, Canada
* Present addresses: Department of Biology, Indiana University, Jordan Hall Rm 325, 1001 E. 3rd Street, Bloomington, Indiana 47405, USA (B.K.B,); Department of Biochemistry, Stanford University School of Medicine, Stanford, California 94305, USA (L.D.)
Correspondence and requests for materials should be addressed to J.S.M. ([email protected]).
A principal challenge in testing the role of natural selection in speciation is to connect the build-up of reproductive isolation between populations to divergence of ecologically important traits. Demonstrations of 'parallel speciation', or assortative mating by selective environment, link ecology and isolation, but the phenotypic traits mediating isolation have not been confirmed. Here we show that the parallel build-up of mating incompatibilities between stickleback populations can be largely accounted for by assortative mating based on one trait, body size, which evolves predictably according to environment. In addition to documenting the influence of body size on reproductive isolation for stickleback populations spread across the Northern Hemisphere, we have confirmed its importance through a new experimental manipulation. Together, these results suggest that speciation may arise largely as a by-product of ecological differences and divergent selection on a small number of phenotypic traits.
