Numerous plants and animals harbor selfish B chromosomes that "drive" or transmit themselves at super-Mendelian frequencies, despite long-term fitness costs to the organism. Currently, it is unknown how B chromosome drive is mediated, and whether B-gene expression plays a role. We used modern sequencing technologies to analyze the fine-scale sequence composition and expression of paternal sex ratio (PSR), a B chromosome in the jewel wasp Nasonia vitripennis. PSR causes female-to-male conversion by destroying the sperm's hereditary material in young embryos to drive. Using RNA interference, we demonstrate that testis-specific expression of a PSR-linked gene, named haploidizer, facilitates this genome elimination-and-sex conversion effect. haploidizer encodes a putative protein with a DNA binding domain, suggesting a functional link with the sperm-derived chromatin.
Copyright © 2020 The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original U.S. Government Works. Distributed under a Creative Commons Attribution NonCommercial License 4.0 (CC BY-NC).