Drosophila yakuba - Tsc1.

Gene Model for the ortholog of Tsc1 in the Drosophila yakuba DyakCAF1 assembly (GCA_000005975.1).

Drosophila yakuba - Tsc1.

Gene Model for Tsc1 in the Drosophila yakuba's DyakCAF1 assembly (GCA_000005975.1).

Retrotransposons Are the Major Contributors to the Expansion of the Drosophila ananassae Muller F Element.

The discordance between genome size and the complexity of eukaryotes can partly be attributed to differences in repeat density. The Muller F element (∼5.2 Mb) is the smallest chromosome in Drosophila melanogaster, but it is substantially larger (>18.7 Mb) in D. ananassae To identify the major contributors to the expansion of the F element and to assess their impact, we improved the genome sequence and annotated the genes in a 1.4-Mb region of the D. ananassae F element, and a 1.7-Mb region from the D element for comparison. We find that transposons (particularly LTR and LINE retrotransposons) are major contributors to this expansion (78.6%), while Wolbachia sequences integrated into the D. ananassae genome are minor contributors (0.02%). Both D. melanogaster and D. ananassae F-element genes exhibit distinct characteristics compared to D-element genes (e.g., larger coding spans, larger introns, more coding exons, and lower codon bias), but these differences are exaggerated in D. ananassae Compared to D. melanogaster, the codon bias observed in D. ananassae F-element genes can primarily be attributed to mutational biases instead of selection. The 5' ends of F-element genes in both species are enriched in dimethylation of lysine 4 on histone 3 (H3K4me2), while the coding spans are enriched in H3K9me2. Despite differences in repeat density and gene characteristics, D. ananassae F-element genes show a similar range of expression levels compared to genes in euchromatic domains. This study improves our understanding of how transposons can affect genome size and how genes can function within highly repetitive domains.

TelePresence Confocal Laser Scanning Microscopy.

The advent of the Internet has allowed the development of remote access capabilities to a growing variety and number of microscopy systems. To date, the confocal microscope has not been included among these systems. At the California State University (CSU) Confocal Microscopy Core Facility, we have established a remote access confocal laser scanning microscope facility that allows users with virtually any type of computer platform to connect to our system. Our Leica TCS NT confocal system is accessible to any authorized user via the Internet by using a free software program called VNC (Virtual Network Computing). Once connectivity is established, remote users are able to control virtually all the functions to conduct real-time image analysis and quantitative assessments of their specimen. They can also move the motorized stage to view different regions of their specimen by using a software program associated with the stage. At the end of the session, all files generated during the session can be downloaded to the user's computer from a link on the CSU confocal website. A number of safeguard features have been developed to ensure security and privacy of data acquired during a remote session.