Thursday, November 26, 2020

Creation Moment 11/27/2020 - GTEx

"Nearly two decades after the initial sequencing of the human genome, a multi-million-dollar, multi-institutional program has just finished its final reporting. 
This was the Genotype Expression Project (GTEx). The goal of
this 10-year study was to look at variations in the genome and see how they affect RNA production, phenotype, and disease. They were able to separate the effects by sex, race, tissue type, and cell type. What they discovered was a treasure trove for Bible believers. The genome is nothing like anyone expected. It is so complex that it was obviously designed by a higher intelligence.

The human genome is much more complicated than essentially any evolutionist imagined. That first sequence was just a peek into the amazingly complex, four-dimensional information system that God so brilliantly engineered.

In days gone by, scientists held to a “one gene, one enzyme” hypothesis. That is, one gene would produce one protein. This came from studying bacterial genomes, which are fairly straightforward. But in more complex organisms, we have discovered a multi-faceted information processing computer in the nucleus, where any particular letter can be incorporated into many different RNAs and proteins, depending on context. Likewise, the fact that we only have about 23,000 protein-coding ‘genes’ yet produce several hundred thousand unique proteins was a massive surprise.

First, the GTEX Consortium gave us a summary of their ‘atlas of genetic regulatory effects across human tissues’. Perhaps unsurprisingly, they discovered that variations in RNA expression and splicing are more common in the coding areas. But only ⅓ of these are affected by cis-acting (in other words, nearby) variants. Thus, long-distance control of genes is quite common, and a lot of variation exists in this system. However, what is more surprising is the fact that the average gene has more than one expressed form. In other words, the variations found in our genomes causes us to produce different RNA versions of nearly all our genes. Since most of this variation is, I believe, created by God, he clearly programmed a huge amount of diversity into the human genome.
 
Oliva et al. wrote the main article about sex differences. They found 13,294 genes associated with sex differences, across all tissues, but only 369 of these had truly significant differences among the sexes. They found a 10-fold difference from one tissue to the next in the number of differentially transcribed genes (from 473 to 4558, depending on tissue type). They claimed that ⅓ of transcriptome is differentially expressed in at least one tissue. Only 4% of these were X-linked, but these had greater differences than autosomal genes. Only 18% were different in only one tissue. These are particularly interesting to me and they do not apply only to the obvious tissue differences between males and females. For example, there was actually more difference in expression profiles of skin and arterial tissue than in breast tissue. They also detected genomic regions with clusters of sex-linked genes, such as the pseudoautosomal region 1 on the X chromosome (for females) and the q arm of chromosome 20 (for males)
 
Demanelis et al. examined the relationship between telomere length and RNA transcripts. Telomeres are the repetitive DNA that exists at the tips of most chromosomes. They are anchored to the
inside of the nuclear membrane when the cell is not dividing and have been associated with longevity (longer telomeres correlate with longer lifespans). They also get shorter with each cell division, conferring upon the cell lineage a certain maximum lifespan. It turns out that relative telomere length varies across tissues and among the sexes. The greatest difference is between blood (short telomeres) and testes (long telomeres). With the exception of the thyroid, telomere length shortens with age in all tissues... Telomere length also varies among individuals and is longest for people with African ancestry, but age is the single greatest contributor. Thus, telomere length has an inherited component but also depends on telomerase activity.
Some of these studies depend on gene expression for detection. Telomerase is not expressed in differentiated tissue. Age affects genetic expression, so does telomere length, and the two interfere with one another. Sadly, a chronic disease burden was associated with shorter telomere length, even after excluding the effects of cancer.
 
Genomic complexity has always argued against Darwinism,  God made an amazingly complex and functional machine when He fashioned Adam out of the dust. It is nothing short of amazing that He could take something as lowly as dirt and make it into something as complicated as the human body."
CMI 
 Then the Lord God formed a man from the dust of the ground and breathed into his nostrils the breath of life, and the man became a living being. Genesis 2:7