Long Room (EUA)

Amoebae diversified at least 750 million years ago, far earlier than expected

Publicado em 28 fevereiro 2019

Brazilian researchers have reconstructed the evolutionary history of amoebae and demonstrated that at the end of the Precambrian period, at least 750 million years ago, life on Earth was much more diverse than suggested by classic theory.

The study, which was supported by São Paulo Research Foundation—FAPESP, revealed eight new ancestral lineages of Thecamoebae, the largest group in Amoebozoa. Thecamoebians are known as testates because of their hard outer carapace or shell.

Interpretations - Evolution - Earth - Atmosphere - Climate

Interpretations of the evolution of Earth's atmosphere and climate change are also affected by the discovery that amoebae are more diverse than previously thought.

In this study, published in the journal Current Biology, researchers affiliated with the University of São Paulo's Bioscience Institute (IB-USP) in Brazil, in partnership with colleagues at the University of Mississippi in the United States, used innovative techniques to reconstruct the phylogenetic (evolutionary) tree of Thecamoeba, which belongs to the order Arcellinida.

Tree - Algorithms - Transcriptomes - Arcellinids - Nature

The new phylogenetic tree was created using mathematical algorithms and the transcriptomes of 19 arcellinids found in nature today. The researchers also established the morphology and composition of the hypothetical ancestors of this group of amoebae and compared them with the fossil record.

The results showed that at least 750 million years ago, ancestors of the thecamoebians were already evolving. This finding indicates that the late Precambrian was more diverse than previously thought.

Conclusions - Combination - Areas—paleontology - Systematics - Field

"We reached our conclusions using a combination of two major scientific areas—paleontology and phylogenetic systematics, the field within biology that reconstructs evolutionary history and studies the patterns of relationships among organisms. In this way, we were able to untangle one of the knots in evolutionary theory about life on the planet," said Daniel Lahr, a professor at IB-USP and lead author of the article.

The researchers completely dismantled the previous classification of thecamoebians. "We succeeded in developing a robust structure and for the first time, discovered...

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