Volume 221, Issue 3, July 2022

This review by Duhart and Mosca fills a unique void in the current literature: it examines the state-of-the-art in technologies designed to examine central synapse formation in Drosophila, comparing the major aspects and highlighting the advantages and disadvantages of multiple systems. It also provides the most comprehensive assessment to date of how synaptic labeling tools have enabled the discovery of molecular mechanisms that underlie synapse formation, organization, and maturation in the Drosophila central nervous system.

To elucidate the molecular history of mammalian LINE-1 elements, Campitelli, Yellan et al. reconstruct functionally and phylogenetically plausible ancestral sequences for dozens of LINE-1 subfamilies. These reconstructions empower investigation into how transcription factor binding to modern fossilized LINE-1s may have arisen through an arms race with their active ancestors. The new models may be able to improve LINE-1 annotations in the human genome; those reconstructed LINE-1 sequences will be useful for functional studies of LINE-1 evolution and contributions to host regulatory networks.

Surendranadh, Arathoon, et al. integrate a large dataset of genotypes and spatial locations with simulations to ask whether the observed distribution of heterozygosity is consistent with random mating with a patchy distribution and with various pollen dispersal scenarios. They find an excess variance in heterozygosity, which reflects significant variation in inbreeding. Simulated matings with leptokurtic pollen dispersal and a spatial pedigree conditional on actual plant locations are also consistent with the observed variation in heterozygosity, indicating that realistic population density and dispersal can explain isolation by distance and the distribution of heterozygosity.