Homeotic transformations suggest mechanisms for rapid evolution diversification in sex combs.

Evolutionary innovations refer to the emergence of new traits, functions, or behaviors in organisms and lineages over time. Although research has demonstrated that such innovations can arise gradually or through small steps (Chouard 2010), the mechanisms by which rapid morphological diversification takes place remain poorly understood (Bailey 2019). To explore this question, we used the evolution of sex combs, as a system (Ho 2018).

Dynamics of changes in apical cell area during sex comb rotation in .

Epithelia are highly dynamic tissues displaying various types of tissue rearrangements (Weliky and Oster, 1990; Taylor and Adler, 2008; Harris and Tepass, 2010; Lee , 2013; Firmino , 2016; Rupprecht , 2017). Here, we describe the dynamics of changes in apical cell area (ACA) in an epithelial system displaying tissue rearrangement resulting in sex comb rotation on the forelegs of male . The sex comb is a row of leg bristles which rotates during morphogenesis (Atallah, 2008; Atallah , 2009; Malagon, 2013).

Live imaging and quantification of circulating potentially metastatic tumor cells in early pupal stage of .

A circulating tumor cell (CTC) is a type of cell that is shed from solid tumors, swept away in the bloodstream or lymphatic system, and has the potential to cause tumorigenesis at a secondary location. Here we describe an early pupal leg system to study CTCs and to compare the CTCs described in this work to those previously studied We quantified cellular parameters such as the number, size, and shape of CTCs, and our findings are consistent with previous studies. Thus, live imaging of CTCs in model organisms can complement and validate previous work in this field and can be an initial step when deciphering how CTCs behave in humans during metastasis.

Rotation of sex combs in Drosophila melanogaster requires precise and coordinated spatio-temporal dynamics from forces generated by epithelial cells.

The morphogenesis of sex combs (SCs), a male trait in many species of fruit flies, is an excellent system in which to study the cell biology, genetics and evolution of a trait. In Drosophila melanogaster, where the incipient SC rotates from horizontal to a vertical position, three signal comb properties have been documented: length, final angle and shape (linearity). During SC rotation, in which many cellular processes are occurring both spatially and temporally, it is difficult to distinguish which processes are crucial for which attributes of the comb.

PP6 Disruption Synergizes with Oncogenic Ras to Promote JNK-Dependent Tumor Growth and Invasion.

RAS genes are frequently mutated in cancers, yet an effective treatment has not been developed, partly because of an incomplete understanding of signaling within Ras-related tumors. To address this, we performed a genetic screen in Drosophila, aiming to find mutations that cooperate with oncogenic Ras (Ras) to induce tumor overgrowth and invasion. We identified fiery mountain (fmt), a regulatory subunit of the protein phosphatase 6 (PP6) complex, as a tumor suppressor that synergizes with Ras to drive c-Jun N-terminal kinase (JNK)-dependent tumor growth and invasiveness.

Evolution of Drosophila sex comb length illustrates the inextricable interplay between selection and variation.

In spite of the diversity of possible biological forms observed in nature, a limited range of morphospace is frequently occupied for a given trait. Several mechanisms have been proposed to explain this bias in the distribution of phenotypes including selection, drift, and developmental constraints. Despite extensive work on phenotypic bias, the underlying developmental mechanisms explaining why particular regions of morphological space remain unoccupied are poorly understood.