The next stage of compiling a complete encyclopedia of DNA elements.
The international ENCODE consortium, consisting of 500 scientists and biologists from many countries of the world announced the completion of the third phase of the global project on compilation of an encyclopedia of functional DNA elements. In 14 articles published in Nature, Nature Methods and Nature Communications, the authors summarize 17 years of experience.
The human genome contains about 20 thousand genes encoding proteins, which account for only about 1.5 percent of the DNA of the human genome.
The international ENCODE research consortium established in 2003 and is intended as a continuation of the project "human Genome" aims at compiling a comprehensive catalog of functional elements in the human genome and the mouse, including genes encoding proteins, non-coding genes and regulatory elements.
All the results obtained in the course of the project, published in the public databases. Thousands of researchers all over the world have used ENCODE data to define genetic changes that influence the emergence of diseases such as cancer, cardiovascular disease and many others.
"When he completed the first draft of the human genome, it became clear that the primary sequence of the genome is a draft, is given in the press release of the Laboratory at cold spring Harbor in the words of one of the participants of the consortium, Professor of the laboratory of Thomas Gingeras (Thomas Gingeras). We knew where the genes, but knowledge of the location of the regulatory mechanisms and loci, it was not enough."
During the third phase of the project the researchers spent almost six thousand new experiments — 4834 involving human samples and 1158 — mice — and added to the online registry of more than 1 200 000 functional elements, regions of non-coding DNA which regulate the transcription of genes, covering 7.9% of the human genome and 3.4% of the genome of the mouse.
Part of the research devoted to the study of the principles governing some of these functional elements.
For example, Michael Snyder (Michael Snyder) from the Medical school of Stanford University in USA and his colleagues studied the interaction of chromatin — complex of DNA and proteins — in 24 types of human cells and found that the differences in the recurrence of chromatin between cells can affect gene expression.
Team Thomas Gingeras study the elements of the genome that instruct cells on how and when to transcribe a DNA sequence into RNA. Scientists were able to identify and describe the molecular characteristics of the five groups of human cells.
"Our work determines, based on gene expression, the main histological types which have traditionally classified human tissue," says Roderic gigo (Roderic Guigó) from the Centre for genomic regulation, one of the authors of the study.
The consortium members say that the elements that control gene function, is entirely encoded in the human genome and knowledge of their organizations can serve as a starting point for the study of disorders of human development. However, despite the obvious progress, many of the elements that affect specific types or status of the genes remain to be identified.
"This encyclopedia is a living resource. It has a beginning, but really has no end. Over time it will only improve and grow" — written in the introductory article, the authors.
In the fourth stage of the study the participants of the ENCODE project plan to focus on new types of analyzed cells and tissues.