Dopman Erik B, Bogdanowicz Steven M, Harrison Richard G
Department of Ecology and Evolutionary Biology, Cornell University, Ithaca, New York 14853, USA.
Genetics. 2004 May;167(1):301-9. doi: 10.1534/genetics.167.1.301.
The E and Z pheromone strains of the European corn borer (ECB) provide an exceptional model system for examining the genetic basis of sexual isolation. Differences at two major genes account for variation in female pheromone production and male behavioral response, components of the pheromone communication system known to be important for mate recognition and mate choice. Strains of ECB are morphologically indistinguishable, and surveys of allozyme and DNA sequence variation have revealed significant allele frequency differences at only a single sex-linked locus, Tpi. Here we present a detailed genetic linkage map of ECB using AFLP and microsatellite markers and map the factors responsible for pheromone production (Pher) and male response (Resp). Our map covers 1697 cM and identifies all 31 linkage groups in ECB. Both Resp and Tpi map to the Z (sex) chromosome, but the distance between these markers (>20 cM) argues against the hypothesis that patterns of variation at Tpi are explained by tight linkage to this "speciation gene." However, we show, through analysis of marker density, that Tpi is located in a region of low recombination and suggest that a second Z-linked reproductive barrier could be responsible for the origin and/or persistence of differentiation at Tpi.
欧洲玉米螟（ECB）的E型和Z型信息素菌株为研究性隔离的遗传基础提供了一个绝佳的模型系统。两个主要基因的差异导致了雌虫信息素产生和雄虫行为反应的变化，而信息素通讯系统的这些组成部分对于配偶识别和配偶选择至关重要。欧洲玉米螟的菌株在形态上无法区分，对同工酶和DNA序列变异的调查显示，仅在一个性连锁位点Tpi上存在显著的等位基因频率差异。在此，我们利用AFLP和微卫星标记构建了欧洲玉米螟的详细遗传连锁图谱，并对负责信息素产生（Pher）和雄虫反应（Resp）的因子进行了定位。我们的图谱覆盖了1697厘摩，确定了欧洲玉米螟的所有31个连锁群。Resp和Tpi都定位于Z（性）染色体，但这些标记之间的距离（>20厘摩）与Tpi处的变异模式是由与这个“物种形成基因”紧密连锁所解释的假设相悖。然而，我们通过对标记密度的分析表明，Tpi位于重组率较低的区域，并提出第二个Z连锁生殖屏障可能是Tpi处分化的起源和/或持续存在的原因。
