Wednesday, February 28, 2018

Epigenetics Buzzword

The DNA code, discovered during the lifetimes of millions of people alive today, provides instructions for simple atoms and molecules of matter to form and assemble themselves into many thousands of proteins. In our early grades, we learned that proteins are the building blocks of life. As young people we neither understood how proteins were assembled from atoms and molecules nor did we understand the process of thousands of proteins assembling themselves into life forms. We took the statement “proteins are the building blocks of life” on simple, child-like faith. But the statement was true!

DNA is the first term in a famous fundamental biological principle: DNA —> RNA —> Protein. DNA, therefore, is the key factor in understanding proteins as the building blocks of life. Most articles on DNA propose that proteins carry the genetic instructions for organisms to develop, grow, function, and reproduce. In the sense that enzymes and hormones are also considered proteins, this statement is true. In the past several decades, a new term has entered our lexicon—epigenetics. This involves heritable changes in gene function that do not involve changes in the DNA sequence. Epigenetics, therefore, takes us far beyond the reality that proteins are the “building blocks of life.” This statement helps us envision the example of physical building blocks at a construction site ready to be assembled into a finished building.

As we contemplate the elements of reproduction, growth, development, and function of a living human (or even any living creature), we realize our life science instruction in early grades or even in high school barely scratched the surface of knowledge of life processes we are gaining today. “Proteins are the building blocks of life” was true but not deeply explanatory. The molecular structure of DNA was revealed in 1953. The genetic code contained in DNA was announced in 1966. Our knowledge of molecular life processes has expanded and continues to expand dramatically.

Among laypersons epigenetics may not be a familiar concept. In terms of the formation of multiple thousands of proteins functioning as building blocks of the body, we have also recently gained knowledge of how hundreds of bodily actions are initiated, controlled, and directed. Epigenetic processes are initiated primarily by DNA methylation, the addition of a methyl (CH3) molecular group to the cytosine base in the DNA molecule. Histone modification is also a process of methylation. At the risk of being frivolous, we might overcome our fear of this chemically technical explanation by a kitchen analogy: A skillful kitchen chef blends just the right quantities of ingredients to his gourmet dishes and prepares them in precisely the correct way and at the proper time.

There are many favorable outcomes of naturally occurring DNA methylation. It has an important role in early embryonic development. Well-publicized phenomena are gene regulation and gene expression—appropriately fixing genes in the “on” or “off” position. Proper cellular differentiation is of greatest importance. Remember that embryonic stem cells are pluripotent, capable of developing into any type of cell. Beneficial heritable gene expression does not depend on the genetic nucleotide sequence. In our previous post (2/21/18), the title “Life’s Developmental Miracle” seems an appropriate descriptor of the processes we describe. 

Without appropriate DNA methylation humans and animals may not manifest their familiar desirable phenotypes—observable physical characteristics. Even though DNA’s genetic coding provides thousands of protein building blocks for life forms, epigenetics tells us that building blocks must be properly assembled using the right tools in the correct way and at the correct time. Understanding the topic of epigenetics is not without challenge. Abnormal methylation is known to cause adverse effects. For example, diseases such as cancer and cardiovascular conditions are worrisome and tragic. Epigenetic processes either benefit or harm living things and may occur either naturally or by the deliberate actions of humans. They are a double-edged sword. Some harmful effects are drugs, pesticides, excessive use of alcohol, tobacco, stress, or even starvation. These cause deleterious effects to the present generation and are sometimes inherited by several generations to follow. With modern medical discoveries also comes the hopeful prospect of medical remediation. 

Scripture passages such as Exodus 20:5, Exodus 34:6-7, Numbers 14:18, and Deuteronomy 5:8-10 could be relevant given our modern understanding of epigenetics. In addition to the theological concept of man’s inherited spiritual deficiency we may better understand the nature of inherited physical illness and frailty. These passages have seemed somewhat troubling but in the light of modern epigenetic knowledge we may gain insight. The statement that God “punishes the children for the sin of the fathers to the third and fourth generation” is a difficult concept. On the other hand, Scripture is filled with many exhortations for righteous living and healthy lifestyles.

The principle of life’s supernatural design is affirmed as humanity has uncovered secrets of the incredibly complex and beautiful DNA code for the production of protein building blocks of living things. To this genetic knowledge we have now added the wonders of epigenetics. Both genetic and epigenetic processes are heritable. They are divine gifts from our Creator, the author of life.     

Wednesday, February 21, 2018

Life's Developmental Miracle

Miracle: A highly improbable or extraordinary event, development, or accomplishment that brings very welcome consequences. The foregoing definition of “miracle” modifies what many people traditionally believed about the term. A traditional definition of miraculous relates to events that are “not explicable by natural or scientific laws.” Immediate physical healing or raising from the dead would be in this category. Such works were typical of many of the works of Christ during his ministry. In our day most would locate the term miracle on a wide definitional spectrum ranging from unusual to extraordinary to clearly supernatural. Based on this inclusive standard, we assign human reproduction to the status of the miraculous.

Recently our family was blessed with the arrival of a sixth grandchild—our fourth grandson. During the past century our understanding of physical events giving rise to production of a new human life have multiplied exponentially. Our knowledge of prenatal events has been transformed from the general to the specific. We now know what is going on at the level of cellular development, differentiation, and regulation. We formerly knew that the infant's body developed. Now we know what sort of miracle this development entails. 

When we first visited our newest grandson after his birth in the hospital, we were overcome with wonder at the beauty of his perfect fingers, toes, other body parts, and overall resemblance to his brothers and sister. At this level, we marveled  appropriately in devotional thankfulness and wonder. When we dig deeper into developmental and regulatory details during the previous nine months, however, we have apt reason to proclaim his formation and existence a “miracle.” Truth be told, we might be more fascinated by details of developmental events during the formation of a new human being inside the womb than sudden transcendent miracle events. In both cases, the power of the Creator is wonderfully manifest.

The story begins with the joining of two monoploid cells called gametes, the male sperm and the female ovum, into one diploid cell known as a zygote which contains all the genetic information necessary to form a new individual. If the latter statement is true, we may see more clearly the rationale behind our opposition to abortion, the tragic destruction of a human life. The issue of abortion, therefore, places a different perspective on “a woman’s right to ‘choose’” if that choice entails the destruction of a human life.  

The development of the living zygote, a one celled particle formed by the union of gametes from a male and a female human being, is appropriately termed a miracle—“a highly improbable or extraordinary event, development, or accomplishment that brings very welcome consequences.” Anyone who has experienced the birth of their own children or grandchildren, or the birth of children of friends or relatives, may vouch for the appropriateness of the superlative adjective “extraordinary.”

Prenatal human development is aptly described as a miracle. The sequence of events is breathtakingly rapid and eventful. The first two weeks comprise the germinal stage. The zygote divides into two, then four, eight, and sixteen cells. At this early stage differentiation of cell types begins. The cell mass soon forms a blastocyst with a small cavity and travels toward the uterus where tissues of the placenta form. The blastocyst arrives at the uterus about five days after fertilization and is implanted in the endometrial cells of the uterus 8-10 days after ovulation. At 12 days the cells of the ectoderm, mesoderm, and endoderm have begun to differentiate. Cells of the mesoderm are functionally distinct from other cell layers of the embryo. Mesoderm cells initiate the synthesis of gene products crucial for formation of many additional differentiated cells as gestation continues during the nine months of pregnancy. From the stem cells of the embryo, 200 different cell types ultimately develop and position themselves at the correct place and time. This may be the ultimate reproductive miracle. A baby has two trillion cells at birth.

As readers study the period of gestation, the time interval from conception to birth, they will certainly encounter an unfamiliar but vitally important term—Gastrulation— the early organization of the blastocyst into its three-layered cell structure. This process ultimately enables the developing body to produce healthy individual organs. This is termed organogenesis. It is a key concept in bioscience. An oft-quoted pronouncement by Lewis Wolpert, pioneering developmental biologist, notes, “It is not birth, marriage, or death but gastrulation which is truly the most important time in your life.” Wolpert’s statement about this event occurring in the first two weeks of human life relates to respect for the miracle of early prenatal development.

When we read the Psalmist’s description of his body being “knit together in my mother’s womb,” we acquire a profound appreciation for the process and wonders of reproduction. Our cursory study of the germinal stage of pregnancy does not even begin to uncover the depth of detail and beauty of earliest prenatal events, not to mention the sequence of events in the months to follow. It is our hope that readers will reinforce their mission to respect, honor, and preserve human life at this stage. The God of Creation is the Author of Life in many dimensions. We honor the Creator and the miracle of life He has authored.  




Sunday, February 11, 2018

Inspirational Eclipses

When public media assign extra hyperbole to celestial events that already possess appeal and fascination, science educators are grateful. Extensive publicity was given to the last two total eclipse events in the last six months. These were unusual closely spaced natural events, worthy of heightened popular interest, attention and explanation. Since summer 2017, Earth residents have experienced two different noteworthy total eclipses—a total solar eclipse visible across the wide areas of the US “lower 48” followed by a total lunar eclipse observable in a majority of the fifty US states. Each event was distinctive in many ways.

To fully enjoy the total solar eclipse careful travel and observational preparations were necessary. The total eclipse was visible in a narrow band only 70 miles wide racing across 14 of the lower 48 US states at a speed of 1691 mph. Estimates of how many people across the US viewed the spectacular totality in person range as high as 20 million. Twelve million residents live in the 70 mile strip. Not all of them observed the event, but several million traveled to the path of totality from a distance.

Observing a total solar eclipse in person is one of the most inspirational natural events imaginable. The occurrence of visible solar totality at any one spot on Earth is incredibly rare. Any single earth location may not be in the narrow path of totality for hundreds of years, perhaps once in 325 years according to one computer analysis. We link our personal account:

In contrast, total lunar eclipses occur roughly once per year—85 times in the 21st century. However, lunar totality might occur during daylight and not be visible except for residents on the night side of our planet. Nevertheless, every 1-3 years the events of a total lunar eclipse may be experienced by residents of half of our planetary globe, barring cloudy conditions. According to my memory, I have observed as many as 15-20 total lunar eclipses during my lifetime. Millions of fellow Earth residents have watched our lunar companion passing into the umbral (total) shadow of earth at least several times during their lifetime. The reason: Earth is a large body casting a very large shadow into space; the Moon is a small body which periodically slips into Earth’s umbra, the planet’s dark shadow. Observers experience a wondrous sense of our location in the celestial scheme!

The eclipse of January 31, 2018 was the only lunar event to qualify as a super blue blood moon eclipse from 1866-2037. Even though this characterization was accurate, observers of that eclipse event may not have noted much difference from other lunar eclipses they had experienced. The so-called “super moon” visually appears slightly larger than ordinary moons throughout the year. Slightly larger moons appear several times per year when the moon swings somewhat closer to Earth in its 27.3 day orbit. Super moons sometimes correspond with total lunar eclipses. Blue moons are not descriptive of the moon’s appearance. Rather, they merely signal a moon phase that occurs as the second full moon in a calendar month—unusual, but not different in a visual sense. And finally, blood moons are descriptive of the dim, subdued color acquired by the moon during total lunar eclipses. Every total lunar eclipse is a blood moon.

Residents of Hawaii and Alaska were able to observe the complete super blue blood moon total lunar eclipse of January 31, 2018, including the hours before and after totality when the satellite was passing into and out of the penumbra, 5 hours 17 minutes to be precise. Residents of Europe were unable to view any part of the lunar eclipse. At the same time Northwest Illinois was experiencing a setting totally eclipsed moon, west coast US California residents observed the moon about two hours before setting. Hawaii and Alaska residents observed the eclipsed moon high in their dark night sky, evidence that we abide on a spherical planet. If they were interested in more esoteric eclipse astronomy, they also experienced the moon passing into the penumbra (partial shadow). One source stated the full Moon passing through the penumbra begins to look a little “dusky” as it approaches Earth’s umbra. This is a subtle phenomenon. When the Moon slowly enters the dark umbral shadow, however, a startling change takes place. There is nothing subtle about it.

Our home planet, our lunar satellite, and our Sun provide a breathtaking celestial system. The last two total eclipses, one solar, one lunar, have highlighted three astronomical players on the stage of Solar System wonders. We close our post with two lines from a 2008 worship chorus, “God you reign” by Lincoln Brewster:

“The skies proclaim, God, you reign.”

“Creation sings, God, you reign.”      




Monday, February 5, 2018

Super Blue Blood Moon Eclipse

The total lunar eclipse on January 31 merited many superlatives from media reporters. After all, no total eclipse had coincided with a blue moon for 152 years and a repeat coincidence will not occur again until 2037. The occurrence appropriately acquired the moniker “super blue blood moon” total lunar eclipse. Our current post provides additional clarity for the actual lunar eclipse event as it unfolded on January 31, 2018 as well as an explanation of its adjective-laden label. 

Let’s dissect the terms super, blue, and blood moons that modify lunar eclipses. (A) Supermoons occur fairly often whether or not an eclipse occurs. Supermoons at FULL phase occur in consecutive order about three times per year. One of the three is sometimes dubbed an “extra close” supermoon because it comes within 357,000 km (about 222,000 miles) of Earth. Supermoons appear somewhat larger in the sky—having as much as 30% more sky area—because they come closer to the Earth in the Moon’s elliptical orbit. In addition, larger than normal NEW moons occur about three times per year because of Earth’s variable elliptical orbit. They are also called supermoons, but non-illuminated new moons are not visible in the sky owing to their proximity to the sun. The term “supermoon” has acquired a certain mystique, but actual supermoons are not very unusual. 

(B) Blue moons acquired their romantic name merely by being the second full moon in a calendar month. Full moons take place about 29.5 days apart, so two full moons in any single month could only occur on days 1 and 30, 1 and 31, or 2 and 31 of any month. Blue moons occur about once every 2.7 years. Only 85 total lunar eclipses occur in the 21st century. It is easy to understand that it would be highly unusual for a total lunar eclipse to take place exactly on a day numbered 30 or 31 on which a full moon also occurs. This would be a calendar-related coincidence. The expression “Once in a blue moon” indicates a highly unusual or rare event. 

(C) Finally, we explain the meaning of “blood” moon. This term is perhaps easiest to explain. During total lunar eclipses a little filtered light from the sun is bent around the earth through its atmosphere and falls upon the moon even though no direct sunlight reaches the moon. The filtered light is reddish in color. Thus, the term “blood moon” has become popular. The reddish glow is much dimmer than normal reflected moonlight, but is still beautifully visible during eclipse events. “Blood moon” is a term widely used for a total lunar eclipse, but it has acquired a mysterious meaning in some quarters.

On the early pre-dawn morning of Wednesday, January 31 my sunroom became the observational venue to watch the progress of the Super Blue Blood Moon Eclipse of 2018 and to write the first few sentences of this post. I noted the progress of the umbra, the total shadow of our home planet, slowly crossing the moon. The visual event began at 5:48 AM with a tiny cookie bite of darkness at one edge. By 6:51 AM totality had begun. I was blessed that the sky during this stage of the eclipse was reasonably clear. Two factors prevented me from seeing the totally eclipsed moon’s blood red color beginning at 6:51 AM. The sky was just beginning to become light in the pre-dawn morning and it had acquired a haze of thin clouds.  

Watching the total shadow of Earth’s umbra slowly creep across the Moon’s surface inspires deep emotions. Humanity inhabits a planet which occasionally casts its eclipsing shadow on the Moon, Earth’s satellite a quarter million miles distant. One may directly perceive that Earth is a much larger body than our lunar companion as we watch the gentle curve of the shadow’s edge slowly creep across its surface. A palpable feeling of wonder, reverence and humility before our Creator grips the thoughtful, contemplative observer. We experience a unique sense of our location in the Solar System and the cosmos.