The biosynthesis of female moth sex pheromone blends is controlled by a number of different enzymes, many of which are encoded by members of multigene families. One such multigene family, the acyl-CoA desaturases, is composed of certain genes that function as key players in moth sex pheromone biosynthesis. Although much is known regarding the function of some of these genes, very little is known regarding how novel genes have evolved within this family and how this might impact the establishment of new sex pheromone blends within a species. We have discovered that several cryptic Δ11 and Δ14 desaturase genes exist in the genomes of the European and Asian corn borers (
Ostrinia nubilalis
and
Ostrinia furnacalis
, respectively). Furthermore, an entirely novel class of desaturase gene has arisen in the
Ostrinia
lineage and is derived from duplication of the Δ11 desaturase gene and subsequent fusion with a retroposon. Interestingly, the genes have been maintained over relatively long evolutionary time periods in corn borer genomes, and they have not been recognizably pseudogenized, suggesting that they maintain functional integrity. The existence of cryptic desaturase genes in moth genomes indicates that the evolution of moth sex pheromone desaturases in general is much more complex than previously recognized.
雌蛾性信息素混合物的
生物合成由许多不同的酶控制,其中许多是由多
基因家族成员编码的。其中一个这样的多
基因家族是酰基
辅酶A脱饱和酶,由某些
基因组成,这些
基因在蛾类性信息素
生物合成中发挥关键作用。虽然对其中一些
基因的功能已知甚多,但对于如何在这个家族中演化新的
基因以及这如何影响物种内新性信息素混合物的建立,知之甚少。我们发现欧洲玉米螟(Ostrinia nubilalis)和亚洲玉米螟(Ostrinia furnacalis)的
基因组中存在几个隐蔽的Δ11和Δ14脱饱和酶
基因。此外,一种全新的脱饱和酶
基因类别已在Ostrinia谱系中出现,并源于Δ11脱饱和酶
基因的复制以及随后与逆转座子的融合。有趣的是,这些
基因在玉米螟
基因组中已经维持了相对较长的演化时间,并且它们没有明显的赝
基因化,表明它们保持了功能完整性。蛾
基因组中隐蔽的脱饱和酶
基因的存在表明,蛾类性信息素脱饱和酶的演化总体上比以前认为的要复杂得多。