近日，发表在《科学公共图书馆—遗传学》（PLoS Genetics ）上的一份新研究报告显示，现在超级市场上贩卖的苹果与红果有着更加密切的关系，而苹果是一种有较好味道的古老物种。
苹果起源于哈萨克斯坦，在那里，它们有许多种令人难以置信的味道和大小。然后，苹果数千年前就沿着丝绸之路开始传播。后来，罗马人将甜苹果从西亚带到了欧洲（欧洲人之前使用这种水果酿造苹果酒）。但是，之后苹果开始被人工种植的历史却十分模糊。
该新研究检测了从西班牙到中国的5个苹果种类的839个苹果样本的DNA片段，梳理了近来野生苹果与种植苹果的交叉影响。研究结果显示，现代苹果最初是由亚洲野生苹果经过种植，进而进化而来的。但是，研究人员也发现欧洲红果——那些挑选出来的抗病、壮实，或有其他特性的红果——也为现代的种植苹果贡献了大量DNA。另外，研究人员在种植苹果中没有发现任何遗传瓶颈迹象——基因种类急剧缩小，这与那些早期种植的大麦、小米、小麦等农作物形成了鲜明对比。（生物谷Bioon.com）
doi:10.1371/journal.pgen.1002703
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New Insight into the History of Domesticated Apple: Secondary Contribution of the European Wild Apple to the Genome of Cultivated Varieties
Amandine Cornille1,2,3*, Pierre Gladieux1,2,3, Marinus J. M. Smulders4, Isabel Roldán-Ruiz5, Fran?ois Laurens6,7,8, Bruno Le Cam6,7,8, Anush Nersesyan9, Joanne Clavel1,2,3, Marina Olonova10, Laurence Feugey6,7,8, Ivan Gabrielyan9, Xiu-Guo Zhang11, Maud I. Tenaillon12, Tatiana Giraud1,2,3
The apple is the most common and culturally important fruit crop of temperate areas. The elucidation of its origin and domestication history is therefore of great interest. The wild Central Asian species Malus sieversii has previously been identified as the main contributor to the genome of the cultivated apple (Malus domestica), on the basis of morphological, molecular, and historical evidence. The possible contribution of other wild species present along the Silk Route running from Asia to Western Europe remains a matter of debate, particularly with respect to the contribution of the European wild apple. We used microsatellite markers and an unprecedented large sampling of five Malus species throughout Eurasia (839 accessions from China to Spain) to show that multiple species have contributed to the genetic makeup of domesticated apples. The wild European crabapple M. sylvestris, in particular, was a major secondary contributor. Bidirectional gene flow between the domesticated apple and the European crabapple resulted in the current M. domestica being genetically more closely related to this species than to its Central Asian progenitor, M. sieversii. We found no evidence of a domestication bottleneck or clonal population structure in apples, despite the use of vegetative propagation by grafting. We show that the evolution of domesticated apples occurred over a long time period and involved more than one wild species. Our results support the view that self-incompatibility, a long lifespan, and cultural practices such as selection from open-pollinated seeds have facilitated introgression from wild relatives and the maintenance of genetic variation during domestication. This combination of processes may account for the diversification of several long-lived perennial crops, yielding domestication patterns different from those observed for annual species.
