A Post-pleistocene Calibrated Mutation Rate from Insect Museum Specimens.

Area of Science:

• Evolutionary Biology
• Molecular Evolution
• Genetics

Background:

• Accurately dating recent species divergence is difficult without molecular calibration points.
• The katydid species *Neoconocephalus lyristes* offers a unique opportunity to calibrate a mutation rate.
• A known biogeographic event, the Mohawk-Hudson Divide, serves as a calibration point.

Purpose of the Study:

• To calibrate a post-Pleistocene, taxa-specific mutation rate for *Neoconocephalus lyristes*.
• To investigate molecular clock models for recent divergence events.
• To compare estimated mutation rates with those of other insect mitochondrial DNA.

Main Methods:

• DNA extraction from museum specimens of *N. lyristes* (Midwest and Atlantic populations).
• Sequencing of the mitochondrial gene COI using custom primers.
• Coalescent analyses employing strict and relaxed molecular clock models in BEAST v1.8.2.

Main Results:

• The strict molecular clock model was not rejected in favor of the relaxed clock model.
• An intraspecific mutation rate of 14.4-17.3 %/myr was calculated using the strict clock model.
• This calculated rate is substantially higher than typical insect mitochondrial DNA mutation rates but aligns with rates from other taxa with recent divergences.

Conclusions:

• The study successfully calibrated a high mutation rate for *N. lyristes* linked to a specific biogeographic event.
• The findings highlight the utility of museum specimens and biogeographic events for molecular clock calibration.
• The derived mutation rate is valuable for dating recent evolutionary events in closely related species.