Braendle Christian, Friebe Ilvy, Caillaud Marina C, Stern David L
Laboratory for Development and Evolution, Department of Zoology, University Museum of Zoology, Downing Street, Cambridge CB2 3EJ, UK.
Proc Biol Sci. 2005 Mar 22;272(1563):657-64. doi: 10.1098/rspb.2004.2995.
Many polyphenisms are examples of adaptive phenotypic plasticity where a single genotype produces distinct phenotypes in response to environmental cues. Such alternative phenotypes occur as winged and wingless parthenogenetic females in the pea aphid (Acyrthosiphon pisum). However, the proportion of winged females produced in response to a given environmental cue varies between clonal genotypes. Winged and wingless phenotypes also occur in males of the sexual generation. In contrast to parthenogenetic females, wing production in males is environmentally insensitive and controlled by the sex-linked, biallelic locus, aphicarus (api). Hence, environmental or genetic cues induce development of winged and wingless phenotypes at different stages of the pea aphid life cycle. We have tested whether allelic variation at the api locus explains genetic variation in the propensity to produce winged females. We assayed clones from an F2 cross that were heterozygous or homozygous for alternative api alleles for their propensity to produce winged offspring. We found that clones with different api genotypes differed in their propensity to produce winged offspring. The results indicate genetic linkage of factors controlling the female wing polyphenism and male wing polymorphism. This finding is consistent with the hypothesis that genotype by environment interaction at the api locus explains genetic variation in the environmentally cued wing polyphenism.
许多多型现象是适应性表型可塑性的例子，即单一基因型会根据环境线索产生不同的表型。这种交替表型出现在豌豆蚜（豌豆蚜属）的有翅和无翅孤雌生殖雌性个体中。然而，对给定环境线索作出反应而产生的有翅雌性个体的比例在不同克隆基因型之间存在差异。有翅和无翅表型也出现在有性世代的雄性个体中。与孤雌生殖雌性不同，雄性个体的翅发育对环境不敏感，由性连锁双等位基因位点aphicarus（api）控制。因此，环境或遗传线索在豌豆蚜生命周期的不同阶段诱导有翅和无翅表型的发育。我们测试了api位点的等位基因变异是否能解释产生有翅雌性个体倾向的遗传变异。我们检测了来自F2杂交的克隆，这些克隆对于替代的api等位基因是杂合或纯合的，检测它们产生有翅后代的倾向。我们发现具有不同api基因型的克隆在产生有翅后代的倾向上存在差异。结果表明控制雌性翅多型现象和雄性翅多态性的因素存在遗传连锁。这一发现与以下假设一致，即在api位点的基因型与环境相互作用解释了环境诱导的翅多型现象中的遗传变异。
