The combat jellyfish revealed the primitive origin of the genomic regulation of animals, indicates a study by a team from the Genomic Regulation Center (CRG) and the National Center for Genomic Analysis (CNAG), in Spain.
This study, published in the Nature magazine, indicates that the ability to control distanced genes, through many tens of thousands of DNA letters, evolved between 650 and 700 million years ago, and probably appeared at the beginning of the evolution of animals, about 150 million years before what was believed.
Life depends on the activation and deactivation of genes at a specific time, and distal genomic regulation allows regions away from the starting point of a gene activate its function, through an additional control layer.
This layer probably helped the first multicellular animals to build types of specialized cells and tissues without having to invent new genes, the study authors explain.
The discovery was possible thanks to the exploration of the genomes of many of the oldest branches of the genealogical tree of the animals, including the combat jellyfish such as the “sea nut” (mnemiopsis leidyi), the platelves, the cnidarians and the sponges.
Genomic regulation occurs even in simpler living beings, but usually in short distances through the DNA sequence, with the ignition or off switch placed right next to a gene.
This type of genomic regulation is basic and probably as old as life on Earth, the researchers maintain.
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They also need long -distance genetic control, or distal regulation, is based on the physical folding of DNA and sophisticated loops, and this allows regions away from the starting point of a gene activate its function.
They consider “probable”, in this sense, that “critical innovation originated in a marine creature, in the common ancestor of all existing animals.”
This animal developed the ability to fold the DNA in a controlled way, creating loops in the three -dimensional space that put in direct contact fragments of distant DNA with each other in a two -dimensional plane.
Dr. Iiana Kim, co -author of the study and researcher of the Genomic Regulation Center (CRG) and the National Center for Genomic Analysis (CNAG), admits that I did not expect that “this layer of complexity was so old.”
Scientists create a 3D map to reveal genomic regulation
The discovery was possible through the exploration of the genomes of many animals and unicellular relatives that are not animals were also studied, but that share a common ancestor.
“You can discover a large amount of new biology watching strange sea creatures,” says Dr. Iiana Kim.
The study co -author and professor of the ICREA (Catalan Research Institution and Advanced Studies), Arnau Sebe Pedrós, explains that they previously compared genomic sequences but that, thanks to new methods, “what mechanisms of gene regulation control the function of genome in all species can be analyzed.”
The team used a micro-C technique to map how the DNA physically folds within the cells of each of the 11 different species they studied.
On a scale, each human cell core contains about two meters of DNA, and the researchers examined 10,000 million sequencing data to build the 3D genome map of each species in detail of those studied.
While there were no evidence of distal regulation in the unicellular relatives of animals, unbiled animals, such as combs comb, plate and cnidarians, had many loops.
Specifically, the jellyfish Peine, Mnemiopsis Leidyi, had more than four thousand loops throughout the genome, a surprising finding since its genome has about 200 million DNA letters.
In comparison, the human genome has 3,100 million letters and our cells can have tens of thousands of loops.
With EFE information
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