Revealing Rotational Characteristics of the Uniflagellate Mutant of Chlamydomonas reinhardtii through DeepLabCut-Based Autotracking.

Tracking eukaryotic flagella and cilia often requires manual clicking, even in the age of digital imaging. We developed an autotracking method using DeepLabCut, a CNN-based, marker-less tracking tool originally designed for animal behavior. Applying this method, we uncovered rotational characteristics of Chlamydomonas reinhardtii uni1 , a uniflagellate mutant. Live uni1 cells predominantly rotated counterclockwise under a coverslip when viewed from above, whereas demembranated models exhibited slower, more clockwise rotation. These differences likely stem from alterations in the three-dimensional flagellar waveform.