Daphnia pulex, also known as the water flea, is a tiny crustacean that plays a crucial role in freshwater ecosystems worldwide. This microscopic species has been extensively studied due to its unique reproductive habits and ability to thrive in stable environments. A recent study by Arizona State University and international colleagues analyzed nearly 1,000 D. pulex specimens and discovered the strength of natural selection on individual genes year by year.
Surprisingly, the team found significant fluctuations in gene variants, even in stable conditions, which could increase the ability to adapt to changing environments while maintaining genetic variation. The study was published in the journal Proceedings of the National Academy of Sciences (PNAS).
This finding challenges traditional notions of studying genetic diversity and divergence as the only evidence for selection pressures. Instead, it shows that evolution works on a more subtle level, with genes located near each other evolving in coordination to speed up adaptation.
Understanding these underlying evolutionary mechanisms is crucial in an era of climate change. By analyzing how species adapt in stable environments, scientists can develop strategies to harden vulnerable food webs against the impacts of climate change.
As the first crustacean to have its genome sequenced back in 2011, D. pulex has been a vital model organism for biologists studying evolution. Its rapid reproduction cycle and sensitivity to environmental pollutants make it an ideal species for testing freshwater toxicity and understanding evolutionary mechanisms.
Source: https://www.popularmechanics.com/science/animals/a62231418/water-flea-evolution/