The extraordinary ability of animals to evolve quickly in response to predators has been demonstrated through the genetic sequencing of a water flea population over nearly two decades.
In a new study published in Nature communication, scientists from the Universities of Birmingham in Great Britain, the Katholieke Universiteit Leuven in Belgium and the Leibniz Institute for Freshwater Ecology and Inland Fisheries (IGB), Berlin, identified more than 300 genes that vary in the genome of the water flea.
These genes, which make up about 3 percent of all sequenced water flea genes, support changes in behavioral and life traits that improve survival when exposed to predators.
Remarkably, in response to predation pressures, evolution takes place within a few generations. It is mediated through what is known as constant genetic variation – the amount of genetic diversity that a given natural population hosts. Research brings the importance of constant genetic diversity to the fore in science to support rapid adaptation. It also underscores that the reduction in the genetic diversity of natural populations has important implications for their ability to adapt to environmental changes.
Lead researcher Dr. Anurag Chaturvedi, currently at the School of Biosciences at the University of Birmingham and a former PhD student at KU Leuven, said: “We were able to quantify the genetic diversity of a particular Daphnia population over almost two decades and clearly show how quickly evolution is developing. ” took place in response to environmental pressures. This type of research will be invaluable in understanding the potential impact of future environmental changes on animal populations. “
The water flea or daphnia is central to the food webs of lakes and ponds. Its life cycle includes a dormant phase that can last for several decades. By awakening sleep stages through resurrection biology, scientists can quantify genetic changes at various points in the past and observe evolution as it occurs in nature.
In the study, the team was able to hatch dormant eggs spanning two decades and sequence the genome of 36 resuscitated daphnia from a fish farming pond. During the two decades, the Daphnia population experienced a transition from no fish predation to high fish predation and back to lower predation. The team was able to uniquely match changes in predation pressure on Daphnia over time with changes in DNA. Indeed, research has been able to link specific changes in Daphnia’s environment to evolution in their genomes.
The team found that the DNA variation required to initiate an evolutionary change that spreads across an entire population required no more than five individual “founding” daphnia from the regional group of daphnia populations.
This surprising result suggests that animal species such as daphnia have high adaptive evolution capabilities because genetic variation is preserved at the landscape level – an important lesson for conservation biology.
Lead researcher Dr. Anurag Chaturvedi stated, “Our ability to study populations that evolve over decades is invaluable to discoveries in both basic and applied science.”
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