Amoeba has diversified more than 750 million years ago, as expected – ScienceDaily

Publicado em 28 fevereiro 2019

Brazilian researchers rebuild the evolution of amoebae's history and demonstrated that at Prekambrian, less than 750 million years ago, they have been much more grounded than the classics of the theory.

The research supported by the São Paulo Research Foundation, Thecamoebae, consists of eight lines of the largest Amoebozoa group. Thecamoebians are known as testates, their outer karapace hard or shell.

The interpretation of the Earth's environment and the evolution of climate change are much more than those previously thought.

In the study, published in the journalCurrent biologyIn Brazil, in collaboration with colleagues from the Mississippi State University in the United States, researchers from the University of Biscay University of Brazil (IB-USP) used innovative reconstruction techniques (evolution) of Thecamoeba tree evolution. Order Arcellinida.

A new phylogenetic tree was created using 19 arcellinido mathematical algorithms and transcripts of nature. The researchers also worked on the hypothetical and morphological background of this amoeba group compared to the fossil record.

The results show that at least 750 million years ago, thecamoebians' ancestors were evolving. This discovery indicates that prebambrian was far more widespread than previously thought.

"We believe that we combine two important scientific areas: paleontology and phylogenetic systematics, in the field of biology that reconstructs the history of evolution and the relationship between organisms, thus twisting a knot on the evolutionary theory of planet life," said Daniel Lahr, IB- USP teacher and article principal author.

Re-classification of amoeboz

The researchers completely disassociated the classification of previous scientists. "We developed a strong structure and for the first time found eight deep lines [from 750 million years ago] Arcellinid was unaware of everything, "said Lahr.

Thecamoebian old classifications were based on shell composition. "Agglutinated and organic divides were found. However, according to our molecular reconstruction, we found that the classification really forms the shell shape," said Lahr.

For several years he asked for an old classification, but he needed more evidence to destroy him. Previous genetic research has shown that classification is not sustainable, but there is not enough new classification to justify a new data.

"The scientific community suspects that it was an amoeba of proven arachnids, and it was quite developed to diversify 750 million years ago. From now on we have proved this hypothesis," he said.

In the past and in the future

According to Lahr, the study shows how microorganisms evolved in the plan. At the end of Precambrian it was a low biotic diversity, only a few bacteria and some protism.

"It was 800 million years ago when oceans became oxygen," said Lahrrek, "which has led to the diversification of eukaryotes, unicellular and multicellular organisms for a long time, because the cell nucleus was isolated by a membrane, the diversification of microorganisms millions of years later in Cambodia.

Research on Current Biology, he added, has a detailed question. "We have already shown that this diagram was pre-Cambrian already in existence and that ocean ocean oxygenation had occurred, and geophysics found that this process was slow and lasted about 100 million years ago," he said.

However, scientists do not know how much pressure this oxygen causes. "Because of the cause, oxygenation brought more niches, eukaryotes were diversified and niches were more competitive. A way of resolving the competition became more and more multilingual," said Lahre.

The study has led to the improvement of today's climate change. "We began to understand the microbial life more effectively in this way," explained Lahre. "Climate change was crucial during the time it was 717 million years ago when Sturtian glacier occurred. It was one of the greatest glacier events."

According to Lahr, these changes may have biological origin. "In order to decide how the past life was changed, we understand a bit more about the climate of the planet and its geology, which will help us to understand the current climate change," he said.


In addition to finding a greater diversity in Prekambri, the research is also innovative, reconstructing the morphology of ancestral ancestors, vase-shaped microfossils (VSM) found in Western pre-fabricated already existing Western states. It was at this time in the main ice rings.

VSMs are fossils called test ameba. They are unicellular and eucaryotic and have an outer skeleton. Significant VSM variants have been documented for the Neoproterozoic Era of 1 million to 541 million years ago and built in Pre-Cambrian.

"It's very different to see how the microorganisms looked at how they evolved in the plan, although fossils lack genetic information to compare morphological and compositional information and whether it is an organic or silicone base, compare comparative form and composition, in this case it is particularly well preserved, Large data is being restructured by current-day thecamoebians, "said Luana Morais, a FAPESP scholarship and a postdoctoral doctoral researcher.

Innovative techniques

In addition to the lack of DNA fossils, the researchers also carried out another obstacle that reconstructed the phylogenetic tree: laboratories can not be cultured and, as a result, genetic sequencing excludes conventional pathways.

The solution to this problem was the use of a cell transcripted cell to study phylogenetics (instead of gene expression, its normal application). "We have sequenced the transcriptomies of ammonia arcellinids using live samples," explained Lah. "This gave us about several thousand genes and about 100,000 amino acids, or 100,000 datapoints have never seen a phylogenetic tree."

The researchers used a transcriptomer-based methodology to extract all MESSERRI RNAs in each cell and convert them into the ADN complement DNA library.

"Our research is a basic single cell transcriptomy, and our laboratory is one of the pioneers around the world," said Lahr. "In this area, technology is revolutionary because it encounters a single person [unicellular] Ameba, isolated and washed, and all laboratory procedures to sequencing the entire transcriptome. "

In the study, researchers selected 250 genes to build a phylogenetic tree. "It's not good to find a single cell when you are studying gene expression, because the resolution is not enough," said Lah. "Evolutionary studies, however, do not matter for the sequence, not the number that the genes indicate, so that this technique can be used to develop tumor cells and adapt them, making an ameba cell taking much more than a tumor cell."

Prior to the development of the technique, the organisms that grow in the laboratory can be sequenced. "It extends the field of research in my field to obtain genetic information obtained from the organisms I have found. Only one or more biodiversity can change the plant," says Lah.

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