The Dobzhansky-Muller model proposes that hybrid incompatibilities are caused by the interaction between genes that have functionally diverged in the respective hybridizing species. Here, we show that Lethal hybrid rescue (Lhr) has functionally diverged in Drosophila simulans and interacts with Hybrid male rescue (Hmr), which has functionally diverged in D. melanogaster, to cause lethality in F1 hybrid males. LHR localizes to heterochromatic regions of the genome and has diverged extensively in sequence between these species in a manner consistent with positive selection. Rapidly evolving heterochromatic DNA sequences may be driving the evolution of this incompatibility gene.

We report a draft sequence for the genome of the domesticated silkworm (Bombyx mori), covering 90.9% of all known silkworm genes. Our estimated gene count is 18,510, which exceeds the 13,379 genes reported for Drosophila melanogaster. Comparative analyses to fruitfly, mosquito, spider, and butterfly reveal both similarities and differences in gene content.

Atomically thin Janus transition metal dichalcogenides (JTMDs) with an asymmetric structure have emerged as a new class of intriguing two-dimensional (2D) semiconductor materials. Using state-of-the-art density functional theory (DFT) calculations, we systematically investigate the structural, electronic, and optical properties of JTMD monolayers and heterostructures. Our calculated results indicate that the JTMD monolayers suffer from a bending strain but present high thermodynamic stability. All of them are semiconductors with a band-gap range from 1.37 to 1.96 eV. They possess pronounced optical absorption in the visible-light region and cover a large range of carrier mobilities from 28 to 606 cm2 V-1 s-1, indicating strong anisotropic characteristics. Significantly, some monolayer JTMDs (e.g., WSSe and WSeTe) exhibit superior mobilities than conventional TMD monolayers, such as MoS2. Moreover, the absolute band-edge positions of the JTMD monolayers are higher than the water redox potential, and most JTMD heterostructures have a type-II band alignment that contributes to the separation of carriers. Our work suggests that the 2D JTMD monolayers are promising for nanoelectronic, optoelectronic, and photocatalytic applications.

Nuclear envelope proteins play important roles in chromatin organization, gene regulation, and signal transduction; however, the physiological role of these proteins remains elusive. We found that otefin (ote), which encodes a nuclear lamin-binding protein [corrected], is essential for germline stem cell (GSC) maintenance. We show that Ote, as an intrinsic factor, is both necessary and sufficient to regulate GSC fate. Furthermore, we demonstrate that ote is required for the Dpp/BMP signaling pathway to silence bam transcription. By structure-function analysis, we demonstrate that the nuclear membrane localization of Ote is essential for its role in GSC maintenance. Finally, we show that Ote physically interacts with Medea/Smad4 at the bam silencer element to regulate GSC fate. Thus, we demonstrate that specific nuclear membrane components mediate signal-dependent transcriptional effects to control stem cell behavior.