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One of the most popular scientific metaphors, "the tree of the life", with its evoluzionari coppers and roots, with groups of bacteria low and multicellular organisms up, stà in order to yield the step to a new symbolic paradigm... According to an article of James To Lake, a molecular biologist of the UCLA, appeared the 9 september on the newspaper "Natures", "the shape to ring expresses very better the concept". "Thanks to the genomic one", say Lake, "hour know that the first eucariota (multicellular organism) have been formed from the fusion of two procarioti (unicellulari organisms)".
All the cellular types presents on our planet belong to two fundamental groups: procarioti and eucarioti. The terms procariota (from the Greek for = before and karion = nucleus) and eucariota (from the good Greek eu =) were coin you to the beginning of the 1960 from Hans Ris. The cells procariote (archeobatteri, eubatteri and alghe blue) are relatively small (with a generally comprised diameter between 1 and 5 µm) and have one somewhat simple inner structure: their DNA is found concentrated in one region of the cytoplasm, without being delimited from some membrane. They are lacking in organuli, to exception of the ribosomi, preplaces to the synthesis of proteins. 
The cells eucariote constitute all the other living organisms (the protisti, the plants, the fungi and the animals, comprised the humans) are the much larger (usually their greater axis are comprised between the 10 and 50 µm) and in they the DNA is enclosed from one membrane, having formed therefore a particular one organulo called nucleus. These cells possess organuli dipped in the cytoplasm, everyone deputy to carry out one particular function.
Until today, although the many theories to care, nobody could say with exactitude as they were you form to you first eucarioti. To how much it seems must in part to the "protobatteri", an ancient group of fotosintetici organisms unicellular, even if today includes also non-fotosintetici bacteria as the bacterium And strains and the pathogenic humans. In other part to the "archeobatteri", than today Fahrenheit degrees can living also to the temperature of boiling (160-230) in warm primaverili sulphureous waters and oceanic geotermali gases, all over the world. 
"At least 2 billions of years ago", continue Lake, "the ancestors of these two groups procarioti have fused the own genomes in order to form the first organism eucariota, like if two various coppers of the tree of the life had been melted in order to form a ring". We have therefore two micro-parents, much antichi of the monkeys. The search, financed from the National Science Foundation, from the Department of Energy, the National Institutes of Health and the NASA' s Astrobiology Institutesi, has been based on an analysis more than 30 genomes lead from Lake and Maria C.
Rivera, one ricercatrice of the department of molecular, cellular Biology and developmental of the astrobiological program of the UCLA. The two have created of the algorithms in order to lead of the mathematical analismi a lot detailed and to study the genomic evolution. "we have followed the distance followed from the geniuses in the time having noticed us of when it has been the fusion" explains Lake. The ring of the life will lead therefore to one better understanding than a fundamental passage of the micro-evolution.
Category: Bio-medical
Type: Glossaries and Dictionaries
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