Dasmahapatra Kanchon K, Silva-Vásquez Armando, Chung Jae-Woo, Mallet James
Galton Laboratory, Department of Biology, University College London, London NW1 2HE, UK.
Biol Lett. 2007 Dec 22;3(6):660-3. doi: 10.1098/rsbl.2007.0401.
Interspecific hybridization occurs regularly in wild Heliconius butterflies, although hybrid individuals are usually very rare. However, hybridization generally occurs only between the most closely related species. We report a rare naturally occurring hybrid between non-sister species and carry out the first genetic analysis of such distant hybridization. Mitochondrial and nuclear genes indicate that the specimen is an F1 hybrid between a female Heliconius ethilla and a male Heliconius melpomene, originating from a group of 13 species estimated to have diverged over 2.5 Myr ago. The presence of such distant natural hybrids, together with evidence for backcrossing, suggests that gene flow across species boundaries can take place long after speciation. Adaptive genes such as those involved in wing coloration could thus be widely shared among members of this highly mimetic genus.
种间杂交在野生的红带袖蝶中经常发生，尽管杂交个体通常非常罕见。然而，杂交一般仅发生在亲缘关系最近的物种之间。我们报道了一种非姐妹物种之间罕见的自然杂交现象，并首次对这种远缘杂交进行了基因分析。线粒体和核基因表明，该标本是一只雌性艾氏红带袖蝶和一只雄性美神红带袖蝶的F1杂交后代，它们源自一个估计在250多万年前就已分化的由13个物种组成的类群。这种远缘自然杂交种的存在，以及回交的证据，表明物种形成很久之后仍可能发生跨物种边界的基因流动。因此，诸如那些参与翅膀颜色形成的适应性基因可能在这个高度拟态的属的成员之间广泛共享。
