Soft Tissue Preservation Mechanism Stabilizes the Case for Earth’s Antiquity

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BY FAZALE RANA – DECEMBER 19, 2018

One of the highlights of the year at Reasons to Believe (well, it’s a highlight for some of us, anyway) is the white elephant gift exchange at our staff Christmas party. It is great fun to laugh together as a staff as we take turns unwrapping gifts—some cheesy, some useless, and others highly prized—and then “stealing” from one another those two or three gifts that everyone seems to want.

Over the years, I have learned a few lessons about choosing a white elephant gift to unwrap. Avoid large gifts. If the gift is a dud, large items are more difficult to find a use for than small ones. Also, more often than not, the most beautifully wrapped gifts turn out to be the biggest letdowns of all.

Giving and receiving gifts isn’t just limited to Christmas. People exchange all types of gifts with one another for all sorts of reasons.

Gifting is even part of the scientific enterprise—with the gifts taking on the form of scientific discoveries and advances. Many times, discoveries lead to new beneficial insights and technologies—gifts for humanity. Other times, these breakthroughs are gifts for scientists, signaling a new way to approach a scientific problem or opening up new vistas of investigation.

Soft Tissue Remnants Preserved in Fossils

One such gift was given to the scientific community over a decade ago by Mary Schweitzer, a paleontologist at North Carolina State University. Schweitzer and her team of collaborators recovered flexible, hollow, and transparent blood vessels from the remains of a T. rex specimen after removing the mineral component of the fossil.1 These blood vessels harbored microstructures with a cell-like morphology (form and structure) that she and her collaborators interpreted to be the remnants of red blood cells. This work showed conclusively that soft tissue materials could be preserved in fossil remains.

Though unexpected, the discovery was a landmark achievement for paleontology. Since Schweitzer’s discovery, paleontologists have unearthed the remnants of all sorts of soft tissue materials from fossils representing a wide range of organisms. (For a catalog of some of these finds, see my book Dinosaur Blood and the Age of the Earth.)

With access to soft tissue materials in fossils, paleontologists have a new window into the biology of Earth’s ancient life.

The Scientific Case for a Young Earth

Some Christians also saw Schweitzer’s discovery as a gift. But for them the value of this scientific present wasn’t the insight it provides about past life on Earth. Instead, they viewed this discovery (and others like it) as evidence that the earth must be no more than a few thousand years old. From a young-earth creationist (YEC) perspective, the survival of soft tissue materials in fossils indicates that these remains can’t be millions of years old. As a case in point, at the time Schweitzer reported her findings, John Morris, a young-earth proponent from the Institute for Creation Research, wrote:

Indeed, it is hard to imagine how soft tissue could have lasted even 5,000 years or so since the Flood of Noah’s day when creationists propose the dinosaur was buried. Such a thing could hardly happen today, for soft tissue decays rather quickly under any condition.2

In other words, from a YEC perspective, it is impossible for fossils to contain soft tissue remnants and be millions of years old. Soft tissues shouldn’t survive that long; they should readily degrade in a few thousand years. From a YEC view, soft tissue discoveries challenge the reliability of radiometric dating methods used to determine the fossils’ ages and, consequently, Earth’s antiquity. Furthermore, these breakthrough discoveries provide compelling scientific evidence for a young earth and support the idea that the fossil record results from a recent global (worldwide) flood.

Admittedly, on the surface the argument carries some weight. At first glance, it is hard to envision how soft tissue materials could survive for vast periods of time, given the wide range of mechanisms that drive the degradation of biological materials.

Preservation of Soft Tissues in Fossil Remains

Despite this first impression, over the last decade or so paleontologists have identified a number of mechanisms that can delay the degradation of soft tissues long enough for them to become entombed within a mineral shell. When this entombment happens, the soft tissue materials escape further degradation (for the most part). In other words, it is a race against time. Can mineral entombment take place before the soft tissue materials fully decompose? If so, then soft tissue remnants can survive for hundreds of millions of years. And any chemical or physical process that can delay the degradation will contribute to soft tissue survival by giving the entombment process time to take place.

In Dinosaur Blood and the Age of the Earth, I describe several mechanisms that likely promote soft tissue survival. Since the book’s publication (2016), researchers have deepened their understanding of the processes that make it possible for soft tissues to survive. The recent work of an international team of collaborators headed by researchers from Yale University provides an example of this growing insight.3

These researchers discovered that the deposition environment during the fossilization process plays a significant role in soft tissue preservation, and they have identified the chemical reactions that contribute to this preservation. The team examined 24 specimens of biomineralized vertebrate tissues ranging in age from modern to the Late Jurassic (approximately 163–145 million years ago) time frame. These specimens were taken from both chemically oxidative and reductive environments.

After demineralizing the samples, the researchers discovered that all modern specimens yielded soft tissues. However, demineralization only yielded soft tissues for fossils formed under oxidative conditions. Fossils formed under reductive conditions failed to yield any soft tissue material, whatsoever. The soft tissues from the oxidative settings (which included extracellular matrices, cell remnants, blood vessel remnants, and nerve materials) were stained brown. Researchers noted that the brown color of the soft tissue materials increased in intensity as a function of the fossil’s age, with older specimens displaying greater browning than younger specimens.

The team was able to reproduce this brown color in soft tissues taken from modern-day specimens by heating the samples and exposing them to air. This process converted the soft tissues from translucent white to brown in appearance.

Using Raman spectroscopy, the researchers detected spectral signatures for proteins and N-heterocycle pyridine rings in the soft tissue materials. They believe that the N-heterocycle pyridine rings arise from the formation of advanced glycoxidation end-products (AGEs) and advanced lipoxidation end-products (ALEs). AGEs and ALEs are the by-products of the reactions that take place between proteins and sugars (AGEs) and proteins and lipids or fats (ALEs). (As an aside, AGEs and ALEs form when foods are cooked, and they occur at high levels when food is burnt, giving overly cooked foods their brownish color.) The researchers noted that spectral features for N-heterocycle pyridine rings become more prominent for soft tissues isolated from older fossil specimens, with the spectral features for the proteins becoming less pronounced.

AGEs and ALEs are heavily cross-linked compounds. This chemical property makes them extremely difficult to break down once they form. In other words, the formation of AGEs and ALEs in soft tissue remnants delays their decomposition long enough for mineral entombment to take place.

Iron from the environment or released from red blood cells promotes the formation of AGEs and ALEs. So do alkaline conditions.

In addition to stabilizing soft tissues from degradation because of the cross-links, AGEs and ALEs protect adjacent proteins from breakdown because of their hydrophobic (water repellent) nature. Water promotes soft tissue breakdown through a chemical process called hydrolysis. But because AGEs and ALEs are hydrophobic, they inhibit the hydrolytic reactions that would otherwise break down proteins that escape glycoxidation and lipoxidation reactions.

Finally, AGEs and ALEs are also resistant to microbial attack, further adding to the stability of the soft tissue materials. In other words, soft tissue materials recovered from fossil specimens are not the original, intact material, because they have undergone extensive chemical alteration. As it turns out, this alteration stabilized the soft tissue remnants long enough for mineral entombment to occur.

In short, this research team has made significant strides toward understanding the process by which soft tissue materials become preserved in fossil remains. The recovery of soft tissue materials from the ancient fossil remains makes perfect sense within an old-earth framework. These insights also undermine what many people believe to be one of the most compelling scientific arguments for a young earth.

Why Does It Matter?

In my experience, many skeptics and seekers alike reject Christian truth claims because of the misperception that Genesis 1 teaches that the earth is only 6,000 years old. This misperception becomes reinforced by vocal (and well-meaning) YECs who not only claim the only valid interpretation of Genesis 1 is the calendar-day view, but also maintain that ample scientific evidence—such as the recovery of soft tissue remnants in fossils—exists for a young earth.

Yet, as the latest work headed by scientists from Yale University demonstrates, soft tissue remnants associated with fossils find a ready explanation from an old-earth standpoint. It has been a gift to science that advances understanding of a sophisticated process.

Unfortunately, for YECs the fossil-associated soft tissues have turned out to be little more than a bad white elephant gift.

Resources:

Endnotes
  1. Mary H. Schweitzer et al., “Soft-Tissue Vessels and Cellular Preservation in Tyrannosaurus rex,” Science 307 (March 25, 2005): 1952–55, doi:10.1126/science.1108397.
  2. John D. Morris, “Dinosaur Soft Parts,” Acts & Facts (June 1, 2005), icr.org/article/2032/.
  3. Jasmina Wiemann et al., “Fossilization Transforms Vertebrate Hard Tissue Proteins into N-Heterocyclic Polymers,” Nature Communications 9 (November 9, 2018): 4741, doi:10.1038/s41467-018-07013-3.
Reprinted with permission by the author
Original article at:
https://www.reasons.org/explore/blogs/the-cells-design/read/the-cells-design/2018/12/19/soft-tissue-preservation-mechanism-stabilizes-the-case-for-earth-s-antiquity

Can Keratin in Feathers Survive for Millions of Years?

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BY FAZALE RANA – AUGUST 10, 2016

I don’t like conflict. In fact, I try to avoid it whenever possible. And that’s part of the reason I never wanted to become directly involved in the young-earth/old-earth controversy that takes place within the church.

Frankly, I find the debate tedious, and a distraction from the real work at hand: helping skeptics and seekers recognize the scientific evidence for God’s existence and Scripture’s reliability.

Of course, if people ask me age-of-the-earth questions, I am quick to explain why I hold to an old-earth/day-age interpretation for Genesis 1 and what I see as biblical, theological, and scientific issues with a young-earth/calendar day interpretation of the Genesis 1 creation account.

Soft Tissues in Fossils and the Age of the Earth

Over the course of the last few years, one question that has come up a lot relates to the discovery of soft tissue remnants in fossils, such as the blood cells and blood vessels remains recovered from a T. rex specimen that age-dates to 68 million years old. Young earth creationists make use of these surprising results to argue that it is impossible for fossils to be millions of years old. They argue that soft tissues shouldn’t survive that long. These materials should readily degrade in a few thousand years. In their view, these finds challenge the reliability of radiometric dating methods used to determine the age of these fossils, and along with it, Earth’s antiquity. Instead, they argue that these breakthrough discoveries provide compelling scientific evidence for a young Earth and support the idea that the fossil record results from a recent global (worldwide) flood.

Because I’m a biochemist—and an old earth creationist—people frequently ask me how I make sense of the T. rex find and the discovery of other types of soft tissue remnants in the fossil remains of other creatures that age-date to several hundred million years, in some cases.

Dinosaur Blood and the Age of the Earth

These queries eventually motivated me to write Dinosaur Blood and the Age of the Earth. And I am glad I did. Aside from the young-earth/old-earth debate, the scientific questions related to soft tissue finds in fossils are captivating.

The central question of Dinosaur Blood and the Age of the Earth centers around soft tissue durability: If radiometric dating is reliable, then how is it possible for soft tissue remnants to persist for millions of years?

Recent work by a research team at North Carolina State University (NC State)—headed up by Mary Schweitzer—helps address this question, specifically focusing on beta-keratin fragments recovered from the fossilized feathers and claws of Shuvuuia deserti and Rahonavis ostromi.1

How Can Keratin Survive in Fossils?

As I discuss in Dinosaur Blood and the Age of the Earth, some biomolecules (such as keratins) form extremely stable structures that delay their degradation. Keratins have a number of structural features (such as extensive crosslinking) that helps explain why fragments of these proteins could survive for tens of millions of years, under the right conditions.2 But my analysis was theoretical. Even though my assessment was based on sound biochemical principles, it would be nice to have some corroborating experimental evidence to support my claims. (The old saying in science applies: “theories guide, experiments decide.”) And that is precisely what the NC State researchers provide in their recent study.

Feather Decomposition

Schweitzer and her team conducted a ten-year experiment to gain insight into the natural degradation processes of feathers (and other biological materials made up of keratins such as skin, claws, beaks, and hair). To do this, they exposed feathers from a Hungarian partridge to a variety of conditions, and then analyzed the samples busing: (1) transmission electron microscopy (TEM) to monitor changes in the fine structure of the feather’s anatomy; and (2) a technique called in situ immunofluorescence to determine if pieces of keratin proteins persisted in the feather remains.

Of particular interest is the feather samples Schweitzer and her team wrapped in aluminum foil and heated in an oven for 10 years at 630°F—conditions used to sterilize glassware. Many paleontologists consider high heat to be a proxy for deep time.

Perhaps it is no surprise, when viewed under a microscope, the macroscopic features of feathers treated at high temperatures were completely lost. Instead the only thing visible were shiny black pieces of “charcoal-like” material. Yet, when examined at high magnification with a TEM, the investigators were able to visualize fragments of feather barbs. Using their immunofluorescence technique, the researchers were able to detect clear evidence of keratin fragments in the sample.

These observations align with my thoughts about keratin’s durability, making it all the more reasonable to think that soft tissue remnants persist in millions-of-years old fossil remains. In fact, when the researchers applied their immunofluorescence to the Shuvuuia desertisamples, once again, they found evidence for keratin fragments in these fossil remains.

Preservation Mechanisms

As I point out in Dinosaur Blood and the Age of the Earth, molecular durability alone isn’t sufficient to account for soft tissue survivability. For soft tissue remnants to persist in fossil, the rate of fossilization has to outpace the rate of soft tissue degradation. When that happens, a mineral ‘casing’ will entomb the soft tissue before it completely decomposes, preserving it for paleontologists to later discover. In addition to molecular durability, scientists have identified a number of mechanisms that contribute to both the degradation and preservation of soft tissues during the process of burial and fossilization.

Along these lines, the NC State scientists speculate on processes that might extend keratin’s survivability in feathers—at least, long enough for mineral entombment to occur. They think one of their observations about the high-heat sample offers a clue. The research team noted that melanosomes (the organelles that harbor pigments, giving feathers their colors) were absent after heating for ten years at 630°F. On this basis, they conclude that paleontologists have made a mistake when they interpret microbodies as melanosomes in fossilized feathers. Instead, they think that the mirobodies derive from microbes.

This reinterpretation is good news for keratin preservation on two accounts. It is true that microbial activity can destroy soft tissues, but the NC State scientists think it can also help speed up the fossilization process leading to the preservation of keratin remnants. How? Because microbes secrete materials (called exopolymeric substances) that promote deposition of minerals, speeding up the entombment of the soft tissue. Additionally, the NC State researchers think that melanosome degradation may also be important. When these organelles break down, they release their contents (eumelanin) which may function like a fixative, slowing down tissue degradation long enough for the soft tissue to be entombed.

The NC State study has unearthed fascinating details regarding feather decomposition and provides key insights that help account for the persistence of keratin in fossilized remains of reptiles, birds, and feathered dinosaurs that date to tens of millions of years old.

Resources
Structure of Collagen Unravels the Case for a Young Earth” by Fazale Rana (Article)
Dinosaur Blood and the Age of the Earth by Fazale Rana (Book)

Endnotes

  1. Alison Moyer, Wenxia Zheng, and Mary Schweitzer, “Keratin Durability Has Implications for the Fossil Record: Results from a 10 Year Feather Degradation Experiment,” PLoS One 11 (July 2016): e0157699, doi:10.1371/journal.pone.0157699.
  2. Fazale Rana, Dinosaur Blood and the Age of the Earth (Covina, CA: RTB Press, 2016), 57–58.
Reprinted with permission by the author
Original article at:
https://www.reasons.org/explore/blogs/the-cells-design/read/the-cells-design/2016/08/10/can-keratin-in-feathers-survive-for-millions-of-years