Genetics and Epigenetics

New findings in genetics and epigenetics are creating new problems for evolution. The simplistic version of neo-Darwinism expects all variation come from genetic mutations, which nature selects for fitness. Non-coding DNA was relegated to the junk pile — trash left over from natural selection, which favors DNA that codes for proteins. In a notion called subfunctionalization, copies of genes might be free to mutate and become new proteins, or decay into “pseudogenes,” one type of junk DNA. As usual, simplistic theories are often wrong. 

How Many Genes?

The Human Genome Project ended with a surprisingly low number of genes. But what if they missed some? Researchers at Yale have been finding genes that were misidentified as non-protein coding due to the methods previous researchers used to annotate them. One of the newly identified genes, they say, plays a key role in the immune system. Are there others? 

The findings suggest many more protein-coding genes and functions may be discovered. “A large portion of important protein-coding genes have been missed by virtue of their annotation,” said first author Ruaidhri Jackson. Without vetting and identifying these genes, “we can’t fully understand the protein-coding genome or adequately screen genes for health and disease purposes.”

he first sentence of their paper in Nature says, “The annotation of the mammalian protein-coding genome is incomplete.” They have identified a “large number of RNAs that were previously annotated as ‘non-protein coding,’” some of which are “potentially important transcripts” able to make protein. Restrictive methods in the past “may obscure the essential role of a multitude of previously undiscovered protein-coding genes.”

Epigenetics in Archaea

Does epigenetic inheritance and regulation work only in eukaryotes? No. Scientists at the University of Nebraska-Lincoln discovered that members of the “simple” kingdom of Archaea also have it. They watched microbes inherit extreme acid resistance in Yellowstone hot springs not through genetics, but through epigenetics.

The surprise is that it’s in these relatively primitive organisms, which we know to be ancient,” said Blum, Charles Bessey Professor of Biological Sciences at Nebraska. “We’ve been thinking about this as something (evolutionarily) new. But epigenetics is not a newcomer to the planet.

The discovery “raises questions … about how both eukaryotes and archaea came to adopt epigenetics as a method of inheritance.” Now they have to confront whether an even earlier common ancestor had it, or whether it evolved twice. “It’s a really interesting concept from an evolutionary perspective,” said a doctoral student involved in the research. Critics of neo-Darwinism might describe those alternatives differently from just “interesting.” Ridiculous, perhaps, or falsifying.

Epigenetics in Plants

Briefly, a paper in PNAS finds that “Partial maintenance of organ-specific epigenetic marks during plant asexual reproduction leads to heritable phenotypic variation.” Why do clones, with identical genomes, differ? The answer is epigenetics. 

We found that phenotypic novelty in clonal progeny was linked to epigenetic imprints that reflect the organ used for regeneration. Some of these organ-specific imprints can be maintained during the cloning process and subsequent rounds of meiosis. Our findings are fundamental for understanding the significance of epigenetic variability arising from asexual reproduction and have significant implications for future biotechnological applications.

Non-Genetic Order

Here’s a cellular phenomenon that really is interesting, because it reveals a newly discovered structural order in the cell membrane. This structural order surely is inherited somehow, but may have little to do with genes. Biochemists had thought for a century that the inner space in the membrane is fluid and disordered, but techniques to probe that space have been difficult because the detergents used disrupt the membrane. Now, researchers at Virginia Commonwealth University, in conjunction with Nobel laureate Joachim Frank, used a new method without detergents. They were surprised — no, startled — to find an orderly hexagonal 3-D structure between the molecules in the lipid bilayer. Is there a reason for this orderly structure?

Where earlier models had shown a fluid, almost structureless lipid layer — one often-cited research paper compared it to different weights of olive oil poured together — the VCU-led team was startled to find a distinct hexagonal structure inside the membrane. This led the researchers to propose that the lipid layer might act as both sensor and energy transducer within a membrane-protein transporter.

“The most surprising outcome is the high order with which lipid molecules are arranged, and the idea they might even cooperate in the functional cycle of the export channel,” said Joachim Frank, Ph.D., of Columbia University, a 2017 Nobel laureate in chemistry and co-author of the paper. “It is counterintuitive since we have learned that lipids are fluid and disordered in the membrane.”

Their paper in PNAS says nothing about genetics, so maybe this comes about through physical interactions of the lipids and the protein channels. Whatever causes this orderly arrangement, it appears to interact with transmembrane channels, adapting to the conformational changes of the proteins, particularly a transporter called AcrB. Without the hexagonal mesh around the channel, and just a disordered fluid, the channels action might be less efficient, like a boxer without a sparring partner beating the air. Not only that, the hexagonal mesh also transmits the channel’s activity down the membrane to its neighbors. Fascinating!

Through defined protein contacts, the lipid bilayer senses the conformational changes that occur in each TM [transmembrane] domain and then transduces effects of these changes through the lipid bilayer to neighboring protomers in a viscous interplay between cavity lipids and the AcrB trimer.

Another Blow to the Central Dogma

Mauro Modesti gives his perspective on a new finding in Science, “A pinch of RNA spices up DNA repair.” The Central Dogma of genetics that views DNA as the master molecule controlling everything downstream, with no feedback, has been suffering since it was first taught the 1960s. In the same issue of Science, a paper reveals that RNA plays an essential role in DNA repair. What does this mean? Modesti explains,

Pryor et al. report the surprising discovery that ribonucleotides are frequently incorporated at broken DNA ends, which enhances repair. This important finding overturns the central dogma of molecular biology by demonstrating that transient incorporation of ribonucleotides in DNA has a biological function.

Genetic Determinism Lives On

The idea that humans are pawns of their genes has a long history, mostly negative. Genetic determinism undermines free will and character, giving people something physical to blame for their problems. Materialists continue the bad habit, though, as shown in this paper in Nature Scientific Reports, “A genetic perspective on the relationship between eudaimonic –and hedonic well-being.” The news from the University of Amsterdam puts it bluntly: “Discovery of first genetic variants associated with meaning in life.” But can something as psychological or even spiritual be reduced to genes? 

They checked DNA samples of 220,000 individuals, and had them answer a questionnaire. The genetic variants, they say, “are mainly expressed in the central nervous system, showing the involvement of different brain areas.” 

“These results show that genetic differences between people not only play a role in differences in happiness, but also in differences for in meaning in life. By a meaning in life, we mean the search for meaning or purpose of life.

Did these researchers ever learn that correlation is not causation? Did they inspect their own genes? Did they answer a questionnaire, saying that they felt eudaimonia when proposing genetic determinism? Did their genes determine their own philosophy of mind? If so, then how can anyone believe them? What are universities teaching scientists these days?

Simplistic notions of neo-Darwinism seemed more plausible before new techniques uncovered the evidence of splendid design going on in cells. If the trend continues, 2019 will be a great year for intelligent design.

Source: https://evolutionnews.org/

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