Small but Mitey: A Gapless Telomere-to-Telomere Assembly of an Unidentified Mite With a Streamlined Genome.

A draft assembly of the rainforest tree Rhodamnia argentea Benth. (malletwood, Myrtaceae) revealed contaminating DNA sequences that most closely matched those from mites in the family Eriophyidae. Eriophyoid mites are plant parasites that often induce galls or other deformities on their host plants. They are notable for their small size (averaging 200 μm), distinctive four-legged body structure, and heavily streamlined genomes, which are among the smallest known of all arthropods. Contaminating mite sequences were assembled into a high-quality gapless telomere-to-telomere nuclear genome. The entire genome was assembled on two fully contiguous chromosomes, capped with a novel TTTGG or TTTGGTGTTGG telomere sequence, and exhibited clear signs of genome reduction (34.5 Mbp total length, 68.6% arachnid Benchmarking Universal Single-Copy Ortholog completeness). Phylogenomic analysis confirmed that this genome is that of a previously unsequenced eriophyoid mite. Despite its unknown identity, this complete nuclear genome provides a valuable resource to investigate invertebrate genome reduction.