Marine Biology and Ecology Research Centre, School of Marine Science and Engineering, Plymouth University, Davy Building, Drake Circus, Plymouth PL4 8AA, UK.
Proc Biol Sci. 2013 Aug 21;280(1769):20131479. doi: 10.1098/rspb.2013.1479. Print 2013 Oct 22.
Understanding the link between ontogeny (development) and phylogeny (evolution) remains a key aim of biology. Heterochrony, the altered timing of developmental events between ancestors and descendants, could be such a link although the processes responsible for producing heterochrony, widely viewed as an interspecific phenomenon, are still unclear. However, intraspecific variation in developmental event timing, if heritable, could provide the raw material from which heterochronies originate. To date, however, heritable developmental event timing has not been demonstrated, although recent work did suggest a genetic basis for intraspecific differences in event timing in the embryonic development of the pond snail, Radix balthica. Consequently, here we used high-resolution (temporal and spatial) imaging of the entire embryonic development of R. balthica to perform a parent-offspring comparison of the timing of twelve, physiological and morphological developmental events. Between-parent differences in the timing of all events were good predictors of such timing differences between their offspring, and heritability was demonstrated for two of these events (foot attachment and crawling). Such heritable intraspecific variation in developmental event timing could be the raw material for speciation events, providing a fundamental link between ontogeny and phylogeny, via heterochrony.
了解个体发生（发育）和系统发生（进化）之间的联系仍然是生物学的主要目标。异时性，即祖先和后代之间发育事件时间的改变，可能是这样的联系，尽管导致异时性的过程被广泛认为是种间现象，但仍不清楚。然而，如果发育事件时间的种内变异是可遗传的，它可以为异时性的起源提供原材料。然而，到目前为止，还没有证明可遗传的发育事件时间，尽管最近的研究确实表明，在池塘蜗牛 Radix balthica 的胚胎发育中，事件时间的种内差异存在遗传基础。因此，在这里，我们使用高分辨率（时间和空间）成像对 R. balthica 的整个胚胎发育进行了成像，以比较 12 个生理和形态发育事件的时间。所有事件的亲代间时间差异很好地预测了它们后代之间的时间差异，并且两个事件（足附着和爬行）的遗传力得到了证明。这种可遗传的发育事件时间的种内变异可能是物种形成事件的原材料，通过异时性为个体发生和系统发生之间提供了一个基本联系。
