Elevated rates of nondisjunction in a selfish X chromosome that causes female meiotic drive in Drosophila testacea
Date
2026
Authors
Clark, Michael W.
Perlman, Steve J.
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Journal ISSN
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Heredity
Abstract
Meiotic drivers are selfish genetic elements that manipulate the process of meiosis to increase their transmission, circumventing Mendel’s Law of equal segregation. Because meiosis fundamentally differs between the sexes, meiotic drivers use different mechanisms and strategies in male and female meiosis. Only one out of the four products of female meiosis can participate in fertilization, so female meiotic drivers attempt to alter chromosome segregation to ensure they end up in the fertilizing gamete. The mechanisms that female meiotic drivers use to alter segregation are not well understood. Here, we study the segregation distortion caused by a recently discovered selfish X chromosome that causes female meiotic drive in the woodland fly Drosophila testacea. We used controlled crosses to test whether one or two copies of this selfish X chromosome cause higher rates of nondisjunction, or chromosome segregation failure, in female flies. We found that females carrying a selfish X chromosome failed to transmit either of their X chromosomes at a significantly greater rate than wildtype females; this was even more pronounced in females with two selfish X chromosomes, creating a large number of sterile sons with an XO genotype. Interestingly and on the other hand, females carrying two selfish X chromosomes almost never transmitted both of their X chromosomes. These results suggest that in D. testacea females that are homozygous for the selfish X chromosome, X chromosomes interfere with each other over segregation. Our results show that female meiotic drive is associated with nondisjunction, resulting in negative fitness consequences, and provides insights into the transmission of this unusual selfish chromosome.
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Centre for Forest Biology
Citation
Clark, M. W. & Perlman, S. J. (2026). Elevated rates of nondisjunction in a selfish X chromosome that causes female meiotic drive in Drosophila testacea. Heredity. https://doi.org/10.1038/s41437-026-00846-5