Rieseberg Loren H, Raymond Olivier, Rosenthal David M, Lai Zhao, Livingstone Kevin, Nakazato Takuya, Durphy Jennifer L, Schwarzbach Andrea E, Donovan Lisa A, Lexer Christian
Department of Biology, Indiana University, Bloomington, IN 47405, USA.
Science. 2003 Aug 29;301(5637):1211-6. doi: 10.1126/science.1086949. Epub 2003 Aug 7.
Hybridization is frequent in many organismal groups, but its role in adaptation is poorly understood. In sunflowers, species found in the most extreme habitats are ancient hybrids, and new gene combinations generated by hybridization are speculated to have contributed to ecological divergence. This possibility was tested through phenotypic and genomic comparisons of ancient and synthetic hybrids. Most trait differences in ancient hybrids could be recreated by complementary gene action in synthetic hybrids and were favored by selection. The same combinations of parental chromosomal segments required to generate extreme phenotypes in synthetic hybrids also occurred in ancient hybrids. Thus, hybridization facilitated ecological divergence in sunflowers.
杂交在许多生物类群中很常见，但其在适应过程中的作用却鲜为人知。在向日葵中，生活在最极端栖息地的物种是古老的杂交种，据推测杂交产生的新基因组合促进了生态分化。通过对古老杂交种和人工合成杂交种进行表型和基因组比较，对这一可能性进行了验证。古老杂交种中的大多数性状差异可以通过人工合成杂交种中的互补基因作用重现，并且受到选择的青睐。在人工合成杂交种中产生极端表型所需的相同亲本染色体片段组合也出现在古老杂交种中。因此，杂交促进了向日葵的生态分化。
