20.500.12556/DiRROS-29927 From Adam's rib the Siberian moth's female W chromosome is derived from its Z counterpart Most lepidopteran species have a WZ/ZZ sex chromosome system, suggesting a common origin. However, the exceptional variability of W chromosomes supports their multiple independent origins. Here, we investigated the genome of the recently formed species, Dendrolimus sibiricus, which is one of the most devastating pests of the boreal forests in Northern Asia. We found that its karyotype consists of 30 pairs of chromosomes and follows the WZ/ZZ sex chromosome system. We produced a chromosome-scale assembly of its female genome and identified the sequences of both sex chromosomes. With the exception of the W chromosome, the D. sibiricus genome displays a very high degree of synteny with genomes of other Dendrolimus representatives. The non-conserved W chromosome is composed entirely of recently acquired sequences, mainly young genomic repeats and a few unique loci derived from subtelomeric regions of the same species' Z chromosome as well as from the genome of the endosymbiotic Wolbachia bacterium. It shares no common ancestral sequences with the W chromosomes of two related species, Dendrolimus tabulaeformis and Lasiocampa quercus. They, in turn, display a similar organization relative to the W of D. sibiricus, including Z-derived loci. The W of D. tabulaeformis also contained multiple fragments of the mitochondrial genome, as seen in classical B chromosomes. We conclude that W chromosomes arose from their Z counterparts recently and independently in these three species. We propose that this mechanism may be a common feature of lepidopteran evolution, counteracting the inevitable degeneration of a non-recombining chromosome through its repeated, complete turnover. evolution of sex chromosomes W chromosome turnover Siberian moth Wolbachia genome assembly Lepidoptera metulji true false true Angleški jezik Slovenski jezik Znanstveno delo 2026-06-09 12:08:26 2026-06-09 12:08:26 2026-06-10 03:48:58 0000-00-00 00:00:00 2026 0 0 Nasl. z nasl. zaslona; Opis vira z dne 9. 6. 2026; str. 1-21 iss. 3 Vol. 43 2026 0000-00-00 Zaloznikova Objavljeno NiDoloceno 0000-00-00 0000-00-00 0000-00-00 595.78:575.1 1537-1719 10.1093/molbev/msag055 280963331 https://academic.oup.com/mbe/article/43/3/msag055/8505840 1 298c2872-63eb-11f1-9215-001a4af901a5 https://dirros.openscience.si/Dokument.php?lang=slv&id=45063 msag055_(1).pdf msag055_(1).pdf 1 4C22C1B151C9197040613F292A0CF3D2 676cfdcf60dc587793d7c81de486228e7ffbf82cd402c7c4951c7269d73a5750 56748ccb-63eb-11f1-9215-001a4af901a5 https://dirros.openscience.si/Dokument.php?lang=slv&id=45064 Gozdarski inštitut Slovenije 0 0 0