一项研究说，在番茄基因组的一个关键位置上的一个跳跃基因的插入能部分解释红番茄和青番茄的味道差异。
Harry Klee及其同事此前把消费者的口味偏好与几种和祖传番茄(heirloom tomatoes)品种的味道相关的挥发性化学物质关联了起来，确定了番茄中的乙酸酯含量越少，人们就越喜欢。红果茄中乙酸酯的总量低于绿果番茄，但是这种差异的原因在很大程度上是未知的。这组作者使用一系列的遗传技术——包括分析番茄的基因组——查明了番茄味道成分差异的根源。
这组作者报告说，红果品种和青果品种之间的挥发酯的含量差异可能与一种跳跃基因的插入有关，这种被称为Copia类逆转录转座子的跳跃基因邻近一种参与红果番茄品种的挥发酯的分解的关键酶。由于这种插入——青果番茄品种缺乏这种插入——逐步提高了这种酶的活动，降低了红番茄的挥发酯含量，这组作者提出它部分解释了为什么许多人更偏爱红番茄而非青番茄的原因。
作者称，关于遗传插入——它在进化上很可能出现于红果番茄品种和青果番茄品种的分离之后——的知识可以帮助育种者改进番茄总体的味道。（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.
