一項(xiàng)研究說，在番茄基因組的一個(gè)關(guān)鍵位置上的一個(gè)跳躍基因的插入能部分解釋紅番茄和青番茄的味道差異。
Harry Klee及其同事此前把消費(fèi)者的口味偏好與幾種和祖?zhèn)鞣?heirloom tomatoes)品種的味道相關(guān)的揮發(fā)性化學(xué)物質(zhì)關(guān)聯(lián)了起來,，確定了番茄中的乙酸酯含量越少，人們就越喜歡,。紅果茄中乙酸酯的總量低于綠果番茄,，但是這種差異的原因在很大程度上是未知的。這組作者使用一系列的遺傳技術(shù)——包括分析番茄的基因組——查明了番茄味道成分差異的根源,。
這組作者報(bào)告說,，紅果品種和青果品種之間的揮發(fā)酯的含量差異可能與一種跳躍基因的插入有關(guān)，這種被稱為Copia類逆轉(zhuǎn)錄轉(zhuǎn)座子的跳躍基因鄰近一種參與紅果番茄品種的揮發(fā)酯的分解的關(guān)鍵酶,。由于這種插入——青果番茄品種缺乏這種插入——逐步提高了這種酶的活動(dòng),，降低了紅番茄的揮發(fā)酯含量，這組作者提出它部分解釋了為什么許多人更偏愛紅番茄而非青番茄的原因,。
作者稱,，關(guān)于遺傳插入——它在進(jìn)化上很可能出現(xiàn)于紅果番茄品種和青果番茄品種的分離之后——的知識(shí)可以幫助育種者改進(jìn)番茄總體的味道。（生物谷Bioon.com）
doi:10.1073/pnas.1216515109
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Role of an esterase in flavor volatile variation within the tomato clade
Charles Goulet, Melissa H. Mageroy, Nghi B. Lam, Abbye Floystad, Denise M. Tieman, and Harry J. Klee
Tomato flavor is dependent upon a complex mixture of volatiles including multiple acetate esters. Red-fruited species of the tomato clade accumulate a relatively low content of acetate esters in comparison with the green-fruited species. We show that the difference in volatile ester content between the red- and green-fruited species is associated with insertion of a retrotransposon adjacent to the most enzymatically active member of a family of esterases. This insertion causes higher expression of the esterase, resulting in the reduced levels of multiple esters that are negatively correlated with human preferences for tomato. The insertion was evolutionarily fixed in the red-fruited species, suggesting that high expression of the esterase and consequent low ester content may provide an adaptive advantage in the ancestor of the red-fruited species. These results illustrate at a molecular level how closely related species exhibit major differences in volatile production by altering a volatile-associated catabolic activity.
