Levy Rebecca C, Kozak Genevieve M, Dopman Erik B
Department of Biology, Tufts University, 200 Boston Ave, Ste. 4700, Medford, MA 02155, USA.
Genes (Basel). 2018 Mar 26;9(4):180. doi: 10.3390/genes9040180.
Speciation often involves the coupling of multiple isolating barriers to produce reproductive isolation, but how coupling is generated among different premating barriers is unknown. We measure the degree of coupling between the daily mating time and seasonal mating time between strains of European corn borer () and evaluate the hypothesis that the coupling of different forms of allochrony is due to a shared genetic architecture, involving genes with pleiotropic effects on both timing phenotypes. We measure differences in gene expression at peak mating times and compare these genes to previously identified candidates that are associated with changes in seasonal mating time between the corn borer strains. We find that the E strain, which mates earlier in the season, also mates 2.7 h earlier in the night than the Z strain. Earlier daily mating is correlated with the differences in expression of the circadian clock genes cycle, slimb, and vrille. However, different circadian clock genes associate with daily and seasonal timing, suggesting that the coupling of timing traits is maintained by natural selection rather than pleiotropy. Juvenile hormone gene expression was associated with both types of timing, suggesting that circadian genes activate common downstream modules that may impose constraint on future evolution of these traits.
物种形成通常涉及多种隔离屏障的耦合以产生生殖隔离，但不同的交配前屏障之间是如何产生耦合的尚不清楚。我们测量了欧洲玉米螟不同品系之间每日交配时间和季节性交配时间的耦合程度，并评估了这样一种假设，即不同形式的异时性耦合是由于共享的遗传结构，涉及对两种时间表型都有多效性影响的基因。我们测量了交配高峰期的基因表达差异，并将这些基因与先前鉴定出的与玉米螟品系之间季节性交配时间变化相关的候选基因进行比较。我们发现，在季节中交配较早的E品系，在夜间的交配时间也比Z品系早2.7小时。每日较早的交配与生物钟基因cycle、slimb和vrille的表达差异相关。然而，不同的生物钟基因与每日和季节性时间相关，这表明时间性状的耦合是由自然选择而非多效性维持的。保幼激素基因表达与两种时间类型都相关，这表明生物钟基因激活了共同的下游模块，这些模块可能对这些性状未来的进化施加限制。
