Science Refutes Creationism

Alcohol found to boost cancer risk by causing genetic mutations in stem cell DNA http://www.bionews.org.uk/page_920717.asp Excerpt: " Drinking alcohol damages blood stem cells by altering their DNA, raising the risk of developing cancer, scientists have found. A breakdown product of alcohol - acetaldehyde - is responsible for the damage, according to researchers at the MRC Laboratory of Molecular Biology in Cambridge. Acetaldehyde can cause irreversible DNA damage in blood stem cells, known as hematopoietic stem cells. These are the stem cells responsible for the constant production of fresh blood. 'How exactly alcohol causes damage to us is controversial,' said Professor Ketan Patel, who led the study which was published in Nature. 'This paper provides very strong evidence that an alcohol metabolite causes DNA damage [including] to the all-important stem cells that go on to make tissues.' The link between alcohol and certain types of cancer has been known for som...

Genetic degradation drives scientists to develop more accurate gene editing technology https://www.wired.com/story/whats-next-for-crispr/ DNA consists mainly of four different bases: guanine (G), cytosine (C), adenine (A), and thymine (T). G makes a pair only with C and A forms a pair with T. Genome's GC content is inclined to change to AT content. This is due to the special feature of the cytosine base: A methyl group (CH3), referred to as an epigenetic marker, may be attached to cytosine. The cell uses these markers for several tasks, the most important of which are gene suppression / activation, the secretion of the gene from transcription, and the modification of expression of the gene, i.e. the expression thereof, according to the adaptation of the organism. Also in cell differentiation, or identity, these markers play an important role. Without the epigenetic markers, the cell is a so-called a pluripotent stem cell that is ready to specialize in any task, as long as it is onl...

Plant germ cells also go through methylation reprogramming - and functionally it is essential https://www.technologynetworks.com/cell-science/news/breakthrough-study-reveals-new-insight-into-immortal-plant-cells-295637 Excerpt: "A new study has revealed an undiscovered reprogramming mechanism that allows plants to maintain fitness down the generations. The John Innes Centre team led by Dr Xiaoqi Feng made the discovery when studying germ cells - cells specialised for sexual reproduction - in flowering plants. Germ cells are often referred to as “immortal” because they can pass their genetic material through the generations. They have been the subject of much scientific scrutiny. This study aimed to solve a long-term debate on whether the germ cells in plants undergo an event of DNA methylation reprogramming at each reproductive cycle. DNA methylation is a modification of DNA, which changes the activity of DNA without changing the genetic sequence. It is a cornerstone epi-genetics ...

An epigenetic seesaw mechanism works like an analog regulator https://bmcgenomics.biomedcentral.com/articles/10.1186/s12864-017-4353-7 Excerpt from abstract: " Background DNA methylation at promoters is largely correlated with inhibition of gene expression. However, the role of DNA methylation at enhancers is not fully understood, although a crosstalk with chromatin marks is expected. Actually, there exist contradictory reports about positive and negative correlations between DNA methylation and H3K4me1, a chromatin hallmark of enhancers. Results We investigated the relationship between DNA methylation and active chromatin marks through genome-wide correlations, and found anti-correlation between H3K4me1 and H3K4me3 enrichment at low and intermediate DNA methylation loci. We hypothesized “seesaw” dynamics between H3K4me1 and H3K4me3 in the low and intermediate DNA methylation range, in which DNA methylation discriminates between enhancers and promoters, marked by H3K4me1 and H3K4m...

Evolutionary biologists are surprised - Mice are able to see colors https://neurosciencenews.com/mouse-color-vision-8197/ Excerpt from abstract:" The M5 Cell: A Color-Opponent Intrinsically Photosensitive Retinal Ganglion Cell Highlights •M5 cells are a morphologically and functionally distinct unique ipRGC type •They have both melanopsin responses and chromatically opponent cone-based signals •They receive color-opponent signal (UV-ON, green-OFF) via Types 6–9 bipolar cells •M5 cells innervate the dorsal lateral geniculate nucleus (dLGN) Summary Intrinsically photosensitive retinal ganglion cells (ipRGCs) combine direct photosensitivity through melanopsin with synaptically mediated drive from classical photoreceptors through bipolar-cell input. Here, we sought to provide a fuller description of the least understood ipRGC type, the M5 cell, and discovered a distinctive functional characteristic—chromatic opponency (ultraviolet excitatory, green inhibitory). Serial electron microsc...

lncRNAs might function as barcodes for identifying genomic addresses for maintaining cellular states http://www.lncrnablog.com/lncrnas-might-function-as-barcodes-for-identifying-genomic-addresses-for-maintaining-cellular-states/?utm_campaign=shareaholic&utm_medium=twitter&utm_source=socialnetwork Excerpt:"Long noncoding RNAs (lncRNAs) have been implicated in diverse biological processes, including embryonic stem cell (ESC) maintenance. However, their functional mechanisms remain largely undefined. Here, researchers from TU Dresden show that the lncRNA Panct1 regulates the transient recruitment of a putative X-chromosome-encoded protein transient octamer binding factor 1 (TOBF1), to genomic sites resembling the canonical Oct-Sox motif. TOBF1 physically interacts with Panct1 and exhibits a cell-cycle-specific punctate localization in ESCs. At the chromatin level, this correlates with its recruitment to promoters of pluripotency genes. Strikingly, mutating an octamer-like...

Cellular programming by 3D folding of the DNA - Incredibly complex mechanism behind the cell differentiation https://medicalxpress.com/news/2017-11-three-dimensional-dna-important-epigenetic-mechanisms.html Excerpt: "During differentiation of pluripotent stem cells to cardiomyocytes, the three-dimensional folding of the DNA reorganizes itself. This reorganization of the DNA architecture precedes and defines important epigenetic patterns. A team lead by private lecturer Dr. Ralf Gilsbach and Stephan Nothjunge, who both conduct research at the University of Freiburg in the Department of Experimental and Clinical Pharmacology and Toxicology headed by Prof. Dr. Lutz Hein, have come to this conclusion. The results suggest that the genome's spatial organization is an important switch for defining cell types, thereby representing a very promising starting point for future reprogramming strategies. The team recently published its results in the scientific journal Nature Communications...