A Staging Scheme for the Development of the Moth Midge Clogmia albipunctata

Abstract

Model organisms, such as Drosophila melanogaster, allow us to address a wide range of biological questions with experimental rigour. However, studies in model species need to be complemented by comparative studies if we are to fully understand the functional properties and evolutionary history of developmental processes. The establishment of new model organisms is crucial for this purpose. One of the first essential steps to establish a species as an experimental model is to carefully describe its life cycle and development. The resulting staging scheme serves as a framework for molecular studies, and allows us to homologise developmental processes between species. In this paper, we have characterised the life cycle and development of an emerging non-drosophilid dipteran model system: the moth midge Clogmia albipunctata. In particular, we focus on early embryogenesis (cleavage and blastoderm cycles before gastrulation), on formation and retraction of extraembryonic tissues, and on formation of the germ line. Considering the large evolutionary distance between the two species (approximately 250 million years), we find that the development of C. albipunctata is remarkably conserved compared to D. melanogaster. On the other hand, we detect significant differences in morphology and timing affecting the development of extraembryonic tissues and the germ line. Moreover, C. albipunctata shows several heterochronic shifts, and lacks head involution and associated processes during late stages of development.

A quantitative atlas of Even-skipped and Hunchback expression in Clogmia albipunctata (Diptera: Psychodidae) blastoderm embryos

“…Our work extends earlier qualitative studies of segmentation gene expression in this species [52-55]. We confirm that the formation of Eve stripes is delayed in C. albipunctata compared to D. melanogaster , and that gap and pair-rule patterns shift anteriorly over time in this species.…”

“…As reported for eve mRNA [54,55], each Eve protein stripe is located more posteriorly in C. albipunctata than its equivalent in D. melanogaster (Figure 6, Figure 7A, Additional file 4: Table S4). In fact, stripes 3–6 are initially located more than one stripe’s width more posterior than their D. melanogaster counterparts (Figure 7A).…”

“…In addition, there seems to be a general delay in the formation of posterior eve stripes [55]. Here, we extend these earlier qualitative studies with a quantitative analysis of Eve expression at the protein level.…”

Heterochronic shifts in germband movements contribute to the rapid embryonic development of the coffin fly Megaselia scalaris

“…This stage begins at egg laying and includes the first two cleavage divisions. The number of cleavage cycles appears to be conserved within the Diptera with D. melanogaster, M. abdita and Clogmia albipunctata all undergoing 14 cleavage cycles before gastrulation (Foe and Alberts, 1983;Jim enez-Guri et al, 2014), I therefore base the timings for M. scalaris development on this observation. Since all cleavage cycles up to C12 are of a very similar duration (approximately 10 min), I infer stage 1 to last for at least 20 min.…”

“…The genus Megaselia forms one of the largest groups among the phorids (one of the earliest branching lineages in the radiation of the cyclorrhaphan flies; see Jim enez- Guri et al, 2013;Wiegmann et al, 2011) and both M. abdita and M. scalaris have emerged as useful models for genetics. In the case of M. scalaris, this has mostly focused on sex determination (Sievert et al, 1997;Traut, 2010Traut, , 1994Traut, 1995, 1990), while the focus with M. abdita has been on embryonic development Rafiqi et al, 2008;Stauber et al, 2008Stauber et al, , 2000Stauber et al, , 1999Wotton et al, 2014).…”