Wednesday, July 26, 2023

Creation Moment 7/27/2023 - Epigenetics SIMPLIFIED

Thank you for making me so wonderfully complex!
Your workmanship is marvelous—how well I know it.
Psalm 139:14 NLT
 
"The field of epigenetics is one of the most exciting and rapidly
expanding scientific research areas in the study of the genome and how it responds adaptively in organisms. 
 
The term epigenetics is derived from genetics plus the Greek prefix epi, which means “on top of” or “in addition to.” In other words, it’s an additional type of genomic language that overlays the DNA code that controls how genes are switched on or off.
 
Epigenetic changes in the genome are modulated dynamically according to sensory input that the body detects from its physical surroundings, signaling molecules it receives from other creatures (e.g., gut microbes), diet, and even stress. In fact, many epigenetic changes can be heritable and affect traits passed along to children and grandchildren. 
 
Two different systems can epigenetically modify an organism’s chromosomes. 
The first and most easily studied system is known as cytosine
methylation
, which is the addition of chemical methyl groups to the actual DNA base molecules or nucleotide letters. 
The second system is the modification of proteins called histones that integrate with the DNA and allow it to be packaged and spatially structured in different ways. 
 
The DNA code comprises the ordered sequence of the nucleotide
letters
A (adenine), C (cytosine), T (tyrosine), and G (guanine). Epigenetic modification of the actual DNA molecule occurs specifically on the cytosines by the addition of small epigenetic tags called methyl groups—hence the term cytosine methylation.
The presence of these methyl tags in the DNA molecule plays a major role in the way that genes are expressed, i.e., turned off and on.
 
In general, when the control regions of genes known as promoters are heavily methylated, the gene is turned down like an adjustable light switch being dimmed
In addition, many other switches called enhancer elements that are around the genome outside of genes can also become methylated, which regulates the level of gene activity as well. 
 
The addition of methyl tags in the writing process is done by enzymes called DNA methyltransferases. In humans and other mammals, scientists have discovered at least three different methyltransferases that function as writers. 
The erasing function of methyl tags is done by enzymes called demethylases, which remove methylcytosines and replace them with regular cytosines using specialized enzymatic machinery. 
 
First, the methylation of DNA and histone modifications are not random features in the genome. These purposeful chemical tags are placed at specific chromatin addresses all over the genome in response to various environmental cues.
Second, complex cellular machinery and surveillance systems must interpret the huge diversity of epigenetic tags not only according to the creature’s environment but also based on the type of cell and tissue in which the chromatin is located. 
Third, for the complete epigenetic system to be passed along during cell growth and to the next generation, there exists yet another separate and necessary system that copies the chromatin profile when the cells are replicated or sperm and egg are produced for reproduction.
The evolutionary story of random mutations and natural selection can’t account for DNA’s exquisitely engineered systems. Only our Creator can." 
ICR