At the beginning of the century, the sequencing of the genomes of different species numerically allowed to know how much we are alike and we are different from them. DNA in this qualitative But more important than the quantitative. In fact, the rice grain has about 50.0000 genes while humans have only about 30,000. Therefore, different projects try to go beyond the numbers and claim to know the different performances of the genome in each animal species. Now an international consortium of researchers has completed a job that compares the functional elements of mouse and human genome and provides details on the differences and similarities between the two. Through this comparison, one can understand why some drugs work differently in mice than in humans, which can be expected if a disease is studied in rodents or when to use another animal to analyze basic aspects of some part of our biology .
The ENCODE Consortium, an acronym for in cyclopedia OR f D NA E lements, It is a thorough analysis of the draft human genome. It began in 2003 in the US and now involved about 30 schools in different countries-including Spain. Throughout these years, we have identified a number of genes with humans and other animals, but their work has more. The last step was now collecting simultaneously several of the most prestigious medical journals: a comparison of mouse and human genome.
A comparative analysis of the functionality of the two genomes has been found that there is a common ‘language’ using molecular-level cells but is flexible enough to change its structure and adapt to processes and functions that are completely different between the two species. For example, certain systems such as immune processes as metabolism or stress response are very different in each and others.
“Most of the differences between mice and humans are from the regulation of gene activity, not the genes themselves,” he said in a statement Michael Beer, professor of biomedical engineering at the Faculty of Medicine, Johns Hopkins University, Baltimore (USA) and a member of the ENCODE Consortium whose results published simultaneously several of the most prestigious medical journals such as Nature, or Sciencie Genome Research, among others. “For mouse is an important model for the investigation of human biology, we need to understand these differences to better interpret our results “.
As explained Roderic Guigó WORLD, one of the principal investigators of the study and coordinator of the Bioinformatics and Genomics program at the Center for Genomic Regulation (CRG), “ This work provides the molecular basis for understand which parts of human biology are represented in mouse biology and which parts . There are processes that are more conserved between the two species and other less as those related to the immune system, among others. Therefore, you could say that to study the response to mouse infections may not be a good model, this is what there is to see now. ”
For detailed analysis of these genomes, the researchers studied 124 types of cells and mouse tissues, including heart, brain, blood, kidney, liver and skin. That work resulted in thousands of data on DNA regions that are active-more open and accessible- and where proteins are produced. Through various mathematical models could identify regulatory regions that are common between the two species. This analysis showed that while mouse genes involved in intracellular processes such as the production of proteins-have a pattern of activity similar to that of humans , the activity of the murine genes linked to the cell surface It is very different, which has implications for the study of cell communication, immunity and certain diseases.
“There are genes whose expression is highly conserved between human and mouse, for example the human heart is expressed very like the mouse, also the case in the lung. But there are other genes that are expressed more similarly among different human tissues and very differently in mice, ie, are specific to each species and not for each organ, as previously thought, “says Guigó.
The knowledge generated by this consortium, a roadmap on the functionality of the genes of these two species may be used and exploited now by many research groups worldwide. “These results build a base for many other researchers exploit this information and a milestone of how science works progresses. They are key to future studies, because they can help to refine the research models of human diseases and further extrapolation of what we see in mice to better understand our pathophysiology, “says Isabel Varelo-Nieto, researcher CIBER for Rare Diseases (CIBERER) and the Biomedical Research Institute of CSIC.
This knowledge Varelo-Nieto stressed that projects of this caliber “make technological tools which can then be implemented more cheaply and easily on other projects are developed. Furthermore, generated information is public and that makes an impact in research, and this is over reversing in society “.
The same view is Lluis Montoliu, researcher at the National Center for Biotechnology (belonging to CSIC) and CIBERER, whose group investigates, through a genetically modified mouse model of a rare disease. “ The importance I give to these results is also to understand how genes work is its application in diagnosis, in sickness “.
However, the differences detected now or already knew the point that the mouse is not a good model for research into neurodegenerative diseases of aging themselves, either for certain cancers such as colon, precisely although cancer is one of the processes may further study based on the results obtained with ENCODE.
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