Genome complexity: DNA 3D layer of gene control (Introduction)

by David Turell , Tuesday, November 21, 2017, 19:37 (2347 days ago) @ David Turell

It is found very important in embryology as the 3-D DNA controls myocardial development:

https://www.sciencedaily.com/releases/2017/11/171121121438.htm

"The genome stores information about an organisms development. Each cell carries this information tightly packed on a two-meter long DNA strand in the cell nucleus and specific epigenetic mechanisms control access to the 'blueprint of life'. Because every cell type in a mammalian organism requires access to genomic areas in a tempo-spatial specific manner, the epigenome is crucial for determining cellular identity. It is already known that various epigenetic mechanisms are associated with cell differentiation. Particularly indispensable is the methylation of DNA, in which methyl groups are attached to specific nucleotides of double-stranded DNA. Recent studies also show that differentiation processes are accompanied by a reorganization of the three-dimensional folding of the DNA. Up until now, however, it has been unclear what comes first during cardiomyocyte differentiation: the reorganization of the DNA's folding in the cellular nucleus or the DNA's methylation -- and whether these mechanisms are dependent on one another.

"In order to address this question, the team lead by the Freiburg pharmacologists used modern sequencing methods. These made it possible to map the three-dimensional genome organization as well as epigenetic mechanisms during the differentiation of cardiomyocytes across the entire genome. For this purpose, the researchers established methods for isolating cardiomyocytes in various developmental stages from healthy mouse hearts. This cell-type-specific analysis was essential to demonstrate that there is a close interplay between epigenetic mechanisms and the spatial folding of the DNA in the cardiomyocytes' nucleus. The comparison of different stages of development showed that the type of spatial folding of DNA defines which methylation patterns are formed and which genes are activated. The researchers proved that the spatial arrangement of the DNA is not dependent on the DNA methylation with cells, among other things, that have no DNA methylation at all. The three-dimensional genome organization is thus a central switchboard for determining cellular identity. In the future, the researchers want to use this switch to control cellular functions."

Comment: A four-chambered mammalian heart has different cardiomycytes for each chamber since each operates for different purposes and different pressures. For example the right ventricle must have much lower pressure than the left ventricle to protect the lung arteries which cannot tolerate high pressure. Embryology is a proof that Darwin had no idea how organisms developed in proposing his tiny-step approach to evolution. Advanced design requires feedback that the new design is successful. Therefore advanced planning to make the right designs for reproduced complex multicellular organisms, which first appeared in the Cambrian Explosion is required. Embryology reeks of design as the only possible source. A designer is required.