A cushy lab life has its evolutionary costs—when it comes to fish, that is

Consider the small animal. Their young are small and transparent, they are cheap and easy to grow, and they produce 200 embryos every 7 days. Their most important feature is that they share a lot of the same genes as humans.

Scientists have found ways to use zebra fish to study a wide range of topics since George Streisinger pioneered the use of the fish in 1972. Researchers at the Kavli Institute of Systems Neuroscience peer into the brains of genetically modified zebra fish to study the brain's wiring system.

A team of researchers realized they had a perfect evolutionary experiment after all those years of domestication. They wondered what had happened to laboratory zebrafish, when it came to a characteristic called plasticity.

"Plasticity allows organisms to adjust to different environments, for example to perform consistently across a wide range of temperatures," said Morgan, who recently completed her PhD at the Norwegian University of Science and Technology.

The researchers conducted an experiment to see if this was the case. Their findings have been published.

The lab temperatures need to be stable.

The optimal temperature for the lab is 28 C, which promotes healthy growth and the best fertility. The researchers observed in their paper that lab zebrafish have adapted to life in small aquaria with lots of other fish, dry food and handling by humans.

Morgan and her colleagues decided to compare the performance of lab and wild zebrafish.

They exposed 300 juvenile lab and 300 juvenile wild zebrafish to different temperatures for 35 days. The range of temperatures that a wild zebrafish might experience was used to pick the temperatures.

After 35 days of acclimatization, both wild and lab fish were subjected to a range of tests, such as swimming activity, maximum swim speed, metabolism and growth rate.

The results showed that the lab fish had lost their plasticity.

She said that if there is a cost, then we would expect that plasticity would be selected against if there is no need to maintain it. We show that there have been many different changes in the organisms, from genetic to the whole organisms, which is quite unique.

They adapt to the environments they live in.

The study shows how two populations have adapted to the environments they are in through evolution, according to the senior author of the paper.

The lab fish have lost their ability to perform well at higher or lower temperatures than they experience in the lab.

The researchers said that the study reminded them that organisms like zebrafish, which have been domesticated over the decades, are not the same as their wild brethren.

The study shows how rapid changes can occur in an organisms.

More information: Rachael Morgan et al, Reduced physiological plasticity in a fish adapted to stable temperatures, Proceedings of the National Academy of Sciences (2022). DOI: 10.1073/pnas.2201919119 Journal information: Proceedings of the National Academy of Sciences Citation: A cushy lab life has its evolutionary costs—when it comes to fish, that is (2022, May 27) retrieved 27 May 2022 from https://phys.org/news/2022-05-cushy-lab-life-evolutionary-costswhen.html This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only.