Meiotic drive shapes rates of karyotype evolution in mammals
Summary
Ingested 2026-04-21. 2 findings extracted and verified.
Findings worth citing
Finding 1 — Karyotype morphology (matched vs. mismatched) in mammals shows no detectable effect on speciation or extinction rates under a BiSSE analysis.
These results suggest that mammals with matched or mismatched karyotypes do not have detectably different net diversification rates. — p. 7
Why this is citable: This directly addresses the long-standing chromosomal speciation hypothesis in mammals and provides a citable negative result against karyotype-driven diversification at macroevolutionary scales.
Counter / limitation: BiSSE is known to produce high false-positive rates on phylogenies with diversification rate heterogeneity, and the authors themselves show elevated false-positive rates for diversification inference on the cetacean tree in their simulations.
Topics: karyotype_evolution, chromosome_number_evolution, diversification_rates, meiotic_drive
Finding 2 — Switches in meiotic drive polarity occur at widely varying rates across mammal subclades, from a mean waiting time of ~10.8 million years in Cetartiodactyla to ~90.9 million years in Primates.
We found the highest rate of polarity switching in Cetartio- dactyla, where the mean waiting time for a transition was 10.8 mil- lion years (Fig. 5A). The lowest rate of polarity switching was in — p. 8–9
Why this is citable: This quantifies how often meiotic drive polarity is inferred to flip across major mammalian subclades, providing citable rate estimates for Cetartiodactyla (~10.8 Myr mean waiting time) and Primates (~90.9 Myr) from the subclade chromePlus analyses.
Counter / limitation: The Primate value is described as a ‘median’ waiting time in the text (page 9: ‘the median rate was almost an order of magnitude longer at 90.9 million years’), not a ‘mean’, so the finding_text slightly misstates the statistic for Primates. Additionally, these rates are inferred from q12 transition parameters on trees representing only 12–30% of extant species per clade, limiting precision.
Topics: karyotype_evolution, chromosome_number_evolution, meiotic_drive, diversification_rates