An automated fossil record collection system

Motivation

Understanding the dynamics of microbial evolution requires precise and continuous sampling of evolving populations. Traditional methods of archiving microbial samples manually are labour-intensive, prone to human error, and often lack the resolution necessary to capture rapid evolutionary changes. To overcome these limitations, we sought to develop an automated system capable of creating a high-resolution fossil record of microbial evolution. Our goal was to design a system that would enable consistent and systematic sampling over extended periods, allowing for detailed retrospective analysis of evolutionary trajectories.

 

System Development

We have developed an automated fossil record system using a Dobot Magician robot arm to collect and archive samples from an ongoing laboratory evolution experiment. The system is programmed to position and transfer liquid samples from the evolution experiment onto the wells of a microplate in a time-resolved manner. To ensure that microbial growth is halted during sample collection, the microplate is maintained at 4°C using a Peltier cooler system. This setup prevents any metabolic activity, preserving the samples in their exact state at the time of collection.

After a day of sample collection, the microplate is automatically transferred to a -20°C freezer, and a new plate is positioned for continued sampling. This automated approach not only maintains a detailed and systematic fossil record of ongoing microbial evolution but does so at an unprecedented resolution and scale. By integrating robotics with precise temperature control, our system significantly enhances the ability to track evolutionary changes over time, providing a powerful tool for studying adaptive dynamics and the mechanisms driving microbial evolution.

This development represents a significant advance in the field of experimental evolution, allowing researchers to capture evolutionary processes in real time with minimal manual intervention, ensuring that no critical evolutionary events are missed. We are now collecting the system design files and protocols for assembly and operation and will upload for open sharing soon.