Large inversions in Lake Malawi cichlids are associated with habitat, lineage, and sex determination
- 1School of Biological Sciences, Georgia Institute of Technology, Atlanta, United States
- 2Department of Biology, University of Maryland, College Park, United States
- 3School of Physics, Georgia Institute of Technology, Atlanta, United States
Abstract
Chromosomal inversions are an important class of genetic variation that link multiple alleles together into a single inherited block that can have important effects on fitness. To study the role of large inversions in the massive evolutionary radiation of Lake Malawi cichlids, we used long-read technologies to identify four single and two tandem inversions that span half of each respective chromosome, and which together encompass over 10% of the genome. Each inversion is fixed in one of the two states within the seven major ecogroups, suggesting they played a role in the separation of the major lake lineages into specific lake habitats. One exception is within the benthic sub-radiation, where both inverted and non-inverted alleles continue to segregate within the group. The evolutionary histories of three of the six inversions suggest they transferred from the pelagic Diplotaxodon group into benthic ancestors at the time the benthic sub-radiation was seeded. The remaining three inversions are found in a subset of benthic species living in deep waters. We show that some of these inversions are linked to XY sex-determination systems but are also likely limited to a subset of total lake species. Our work suggests that inversions have been under both sexual and natural selection in Lake Malawi cichlids and that they will be important to understanding how this adaptive radiation evolved.
Related
- Salinity is associated with habitat use and mitochondrial lineage diversity in halophilic Ephydra flies (Diptera: Ephydridae)
- Reconstruction of the gastropod ancestral karyotype reveals lineage-specific chromosomal evolution and adaptations during habitat transitions
- Lens species genome assemblies reveal evolutionarily fragile chromosomes associated with pericentric inversions
- Cascading fishery collapse associated with thermal habitat degradation, marine heatwaves, and predator influx
- HOXA3 Knockdown Impairs hESC-Derived Thymic Epithelial-like Cell Differentiation and CXCL12-Associated Early T-Lineage Support
BibTeX
@article{kumar2026large,
title = {{Large inversions in Lake Malawi cichlids are associated with habitat, lineage, and sex determination}},
author = {Nikesh M Kumar and Taylor L Cooper and Thomas D Kocher and Jeffrey Todd Streelman and Patrick T McGrath},
journal = {eLife},
year = {2026},
month = nov,
doi = {10.7554/elife.104923},
url = {https://elifesciences.org/articles/104923},
note = {CC BY 4.0},
}
RIS
TY - JOUR
TI - Large inversions in Lake Malawi cichlids are associated with habitat, lineage, and sex determination
AU - Nikesh M Kumar
AU - Taylor L Cooper
AU - Thomas D Kocher
AU - Jeffrey Todd Streelman
AU - Patrick T McGrath
PY - 2026
DA - 2026/11/06
JO - eLife
DO - 10.7554/elife.104923
UR - https://elifesciences.org/articles/104923
AB - Chromosomal inversions are an important class of genetic variation that link multiple alleles together into a single inherited block that can have important effects on fitness. To study the role of large inversions in the massive evolutionary radiation of Lake Malawi cichlids, we used long-read technologies to identify four single and two tandem inversions that span half of each respective chromosome, and which together encompass over 10% of the genome. Each inversion is fixed in one of the two states within the seven major ecogroups, suggesting they played a role in the separation of the major lake lineages into specific lake habitats. One exception is within the benthic sub-radiation, where both inverted and non-inverted alleles continue to segregate within the group. The evolutionary histories of three of the six inversions suggest they transferred from the pelagic Diplotaxodon group into benthic ancestors at the time the benthic sub-radiation was seeded. The remaining three inversions are found in a subset of benthic species living in deep waters. We show that some of these inversions are linked to XY sex-determination systems but are also likely limited to a subset of total lake species. Our work suggests that inversions have been under both sexual and natural selection in Lake Malawi cichlids and that they will be important to understanding how this adaptive radiation evolved.
SN - 2050-084X
ER -