02 de març 2015

Beyond the genome

FORUM Epigenomics. Roadmap for regulation. Diseases mapped

My suggestion for today. Have a look at the papers in Nature on epigenome, and at the following figure:

The Roadmap Epigenomics Project has produced reference epigenomes that provide information on key functional elements controlling gene expression in 127 human tissues and cell types, and encompassing embryonic and adult tissues, from healthy individuals and those with disease. a, Many of the adult tissues investigated were broken down by cell type or region — blood into several types of immune cell, for instance, and the brain into regions including the hippocampus and dorsolateral prefrontal cortex. Tissue samples and cells were subjected to a range of epigenomic analyses, along with genome sequencing and genome-wide association studies (GWAS). b, Embryonic stem (ES) cells, which are taken from the embryo at the 'blastocyst' stage and can give rise to almost every cell type in the body, were used to analyse, for example, the differentiation of stem cells into different neuronal lineages. The ES-cell-derived cell lines underwent the same epigenomic analyses as the tissue samples.

The key article, here.Tissues and cell types profiled:

For decades, biomedical science has focused on ways of identifying the genes that contribute to a particular trait, or phenotype. Approaches such as genome-wide association studies (GWAS) identify locations in thhuman genome at which variations in DNA sequence are linked to specific phenotypes, but if the variant is located in a region of DNA that does not encode a protein, such studies rarely provide insights into the regulatory mechanisms underlying the association. In these cases, comprehensive epigenomic analyses can provide the missing link between genomic variation and cellular phenotype.

If this is so, why are governments reluctant to introduce a ban on genetic tests with spurious associations between genome and diseases?

PS. Manel Esteller in DM.