Evolution of pattern formation in insects

多胚胎繁殖指的是一种独特的生殖形式，即一个卵子产生多个后代，使物种的生殖能力最大化。对昆虫多胚胎现象的研究有可能解决发育进化中的一个关键问题：发育新颖性是如何产生的？昆虫的多胚性代表了一种发育的新颖性，因此前体结构和进化过程基本上都是未知的。花冠冠蜂是一种多胚胎寄生蜂，经历完全卵裂，尽管它与果蝇有较近的亲缘关系，但它与典型的昆虫早期发育程序有很大的偏离。Copidosoma的发育包括三个阶段：早期卵裂，导致形成单一的增殖性桑椹；新的增殖期，产生数千个胚胎；以及形态发生阶段，单个胚胎的图案化发生。在此之前，我们已经通过激光消融的方法证明：在4-细胞期的胚胎中，种姓命运和胚胎增殖是由单个细胞控制的，这也是生殖系的特征。这种决定因素对特定细胞的不同分配是在胚胎增殖和模式形成过程中对单个基因进行功能剖析的起点。

Polyembryony refers to a unique form of reproduction in which a single egg results in multiple progeny, maximizing the reproductive capacity of the species. Study of the phenomenon of polyembryony in insects has the potential for addressing one of crucial questions in the evolution of development: How do developmental novelties arise? Polyembryony in insects represents a developmental novelty whereby both precursor structure and evolutionary processes are basically unknown. Copidosoma floridanum is a polyembryonic parasitic wasp that undergoes total cleavage and despite its relative close relatedness to Drosophila exhibits a major deviation from the canonical insect early developmental program. Copidosoma development consists of three phases: early cleavages, which leads to formation of a single proliferative morula; the novel proliferative phase, that generates thousands of embryos; and the morphogenetic phase, where the patterning of individual embryos takes place. Previously, we have shown by laser ablation that caste fate and embryo proliferation in Copidosoma are regulated by a single cell at the four-cell-stage embryo, which also specifies the germ line. This differential allocation of determinants to a specific cell serves as a starting point for the functional dissection of individual genes in the process of embryo proliferation and patterning.