The Language of God: A Scientist Presents Evidence for Belief

by Francis S. Collins

The profound difficulties in defining a convincing pathway for life’s origin have led some scientists, most notably Francis Crick (who with James Watson discovered the DNA double helix), to propose that life forms must have arrived on Earth from outer space, either carried by small particles floating through interstellar space and captured by Earth’s gravity or even brought here intentionally (or accidentally) by some ancient space traveler.

A word is in order here about an objection often raised by some critics to any possibility of the spontaneous origin of life on Earth, based on the Second Law of Thermodynamics. The Second Law states that in a closed system, where neither energy nor matter can enter or leave, the amount of disorder (more formally known as “entropy”) will tend to increase over time. Since life forms are highly ordered, some have argued that it would therefore be impossible for life to have come into being without a supernatural creator. But this betrays a misunderstanding of the full meaning of the Second Law: order can certainly increase in some part of the system (as happens every day when you make the bed or put away the dishes), but that will require an input of energy, and the total amount of disorder in the entire system cannot decrease. In the case of the origin of life, the closed system is essentially the whole universe, energy is available from the sun, and so the local increase in order that would be represented by the first random assembly of macromolecules would in no way violate this law.

If God’s intention in creating the universe was to lead to creatures with whom He might have fellowship, namely human beings, and if the complexity required to start the process of life was beyond the ability of the universe’s chemicals to self-assemble, couldn’t God have stepped in to initiate the process?

A word of caution is needed when inserting specific divine action by God in this or any other area where scientific understanding is currently lacking. From solar eclipses in olden times to the movement of the planets in the Middle Ages, to the origins of life today, this “God of the gaps” approach has all too often done a disservice to religion (and by implication, to God, if that’s possible). Faith that places God in the gaps of current understanding about the natural world may be headed for crisis if advances in science subsequently fill those gaps. Faced with incomplete understanding of the natural world, believers should be cautious about invoking the divine in areas of current mystery, lest they build an unnecessary theological argument that is doomed to later destruction.

There are good reasons to believe in God, including the existence of mathematical principles and order in creation. They are positive reasons, based on knowledge, rather than default assumptions based on (a temporary) lack of knowledge.

For example, only single-celled organisms appear in sediments that are older than about 550 million years, although it is possible that more complicated organisms existed prior to this time. Suddenly, approximately 550 million years ago, a great number of diverse invertebrate body plans appear in the fossil record. This is often referred to as the “Cambrian explosion,” and is chronicled in highly readable form by the late Stephen Jay Gould, the most passionate and lyrical writer on evolution of his generation, in his book Wonderful Life. Gould himself questioned how evolution could account for the remarkable diversity of body plans that appeared in such a short span of time. (Other experts have been much less impressed with the claim that the Cambrian represents a discontinuity in life’s complexity, though their writings have been less widely distributed to the general public. The so-called Cambrian explosion might, for example, reflect a change in conditions that allowed fossilization of a large number of species that had actually been in existence for millions of years.)

Current evidence suggests that the land remained barren until about 400 million years ago, at which point plants appeared on dry land, derived from aquatic life forms. A scarce 30 million years later, animals had also moved onto land. At one time, this step pointed to another gap: there appeared to be few transitional forms between sea creatures and land-dwelling tetrapods in the fossil record. Recent discoveries, however, have documented compelling examples of just this kind of transition.3

Beginning about 230 million years ago, dinosaurs dominated the earth. There is now general acceptance that their reign came to a sudden and catastrophic end approximately 65 million years ago, at the time of the collision of planet Earth with a large asteroid that fell in the general vicinity of what is now the Yucatan peninsula. Fine ash kicked up by this horrendous collision has been identified around the world, and the catastrophic climate changes that occurred from this vast amount of dust in the atmosphere apparently were too much for the dominant dinosaur species, leading to their demise and the subsequent rise of mammals.

We probably wouldn’t be here if that asteroid had not hit Mexico.

Most of us have a particular interest in the fossil record of humans, and here too the discoveries of the last few decades have been profoundly revealing. Bones of more than a dozen different hominid species have been discovered in Africa, with steadily increasing cranial capacity.

The first specimens we recognize as modern Homo sapiens date from about 195,000 years ago. Other branches of hominid development appear to have encountered dead ends: the Neanderthals that existed in Europe until 30,000 years ago, and the recently discovered “hobbits,” tiny people with small brains who lived on ...

While there are many imperfections of the fossil record, and many puzzles remain to be solved, virtually all of the findings are consistent with the concept of a tree of life of related organisms. Good evidence exists for transitional forms from reptiles to birds, and from reptiles to mammals. Arguments that this model cannot explain certain species, such as whales, have generally fallen by the wayside as further investigation has revealed t...

In 1859, faced with the possibility of being scooped by Alfred Russel Wallace, he finally wrote and published his ideas in the profoundly influential book The Origin of Species.

“When the views advanced by me in this volume, and by Mr. Wallace, or when analogous views on the origin of species are generally admitted, we can dimly foresee that there will be a considerable revolution in natural history.”4 Darwin proposed

The Origin of Species engendered immediate and intense controversy, though the reaction from religious authorities was not as universally negative as is often portrayed today. In fact, the notable conservative Protestant theologian Benjamin Warfield of Princeton accepted evolution as “a theory of the method of the divine providence,”5 while arguing that evolution itself must have had a supernatural author.

Furthermore, far from his being ostracized by the religious community, Darwin was buried in Westminster Abbey.

“I see no good reason why the views given in this volume should shock the religious feelings of anyone…. A celebrated author and divine has written to me that he ‘has gradually learned to see that it is just as noble a conception of the deity to believe that he created a few original forms capable of self-development into other and needful forms, as to believe that he required a fresh act of creation to supply the voids caused by the action of his laws.’ ”6

“There is grandeur in this view of life, with its several powers, having been originally breathed by the Creator into a few forms or into one; and that, whilst this planet has gone cycling on according to the fixed law of gravity, from so simple a beginning, endless forms most beautiful and most wonderful have been, and are being evolved.”7

“the extreme difficulty, or rather the impossibility, of conceiving this immense and wonderful universe, including man with his capacity for looking far backwards and far into futurity, as the result of blind chance or necessity. When thus reflecting I feel compelled to look to a First Cause having an intelligent mind in some degree analogous to that of man; and I deserve to be called a Theist.”

Mendel was the first to demonstrate that inheritance could come in discrete packets of information. Through painstaking experiments with pea plants in the garden of his monastery, he concluded that hereditary factors involved in such attributes as the wrinkled or smooth appearance of peas were controlled by mathematical rules. He didn’t know what a gene was, but his observations suggested that something like genes must exist.

At first, scientists had no idea how the program was actually “run.” This puzzle was neatly solved by the identification of “messenger RNA.” The DNA information

How deeply satisfying is the digital elegance of DNA!

Evolution, as a mechanism, can be and must be true. But that says nothing about the nature of its author. For those who believe in God, there are reasons now to be more in awe, not less.

The cause of this “hereditary persistence of fetal hemoglobin” was of intense interest, because if we could learn how to trigger it on purpose in anyone, it could greatly reduce the ravages of sickle-cell anemia. Even 20 percent of fetal hemoglobin in the red blood cells of someone with sickle cell disease would essentially eliminate the painful crises and progressive organ damage.

will never forget the day when my sequencing effort revealed a G instead of a C in a specific position just “upstream” of one of the genes that triggered fetal hemoglobin production. This single letter alteration turned out to be responsible for leaving the fetal program switched on in adults. I was thrilled but exhausted—it had taken eighteen months to discover this single altered letter of the human DNA code.

Furthermore, there were long stretches of DNA in between genes that didn’t seem to be doing very much; some even referred to these as “junk DNA,” though a certain amount of hubris was required for anyone to call any part of the genome “junk,” given our level of ignorance.

That was accomplished, to the astonishment and delight of scientists and families alike, in 1985—and demonstrated that the CF gene must reside somewhere within a 2 million base-pair segment of DNA on chromosome 7. But the hard part had really just begun. To employ an analogy I often used at that time to explain why this was such a hard problem, the search was like looking for a single burned-out lightbulb in the basement of a house somewhere in the United States.

That was neatly engineered in the United States by the new director of the genome project, none other than Jim Watson himself, the codiscoverer of the DNA double helix. Watson, at that time the unrivaled rock star of biology, convinced Congress to take a risk on this new endeavor.

For me, as a believer, the uncovering of the human genome sequence held additional significance. This book was written in the DNA language by which God spoke life into being. I felt an overwhelming sense of awe in surveying this most significant of all biological texts. Yes, it is written in a language we understand very poorly, and it will take decades, if not centuries, to understand its instructions, but we had crossed a one-way bridge into profoundly new territory.

When we survey the vast expanse of the human genome, 3.1 billion letters of the DNA code arrayed across twenty-four chromosomes, several surprises are immediately apparent.

One surprise is just how little of the genome is actually used to code for protein. Though limitations of both our experimental and computational methods still prevent a precise estimate, there are only about 20,000–25,000 protein-coding genes in the human genome.

That was especially shocking in the context of the fact that the gene counts for other simpler organisms such as worms, flies, and simple plants seem to be in about the same range, namely around 20,000.

The average educated English speaker has a vocabulary of about 20,000 words.

At the DNA level, we are all 99.9 percent identical. That similarity applies regardless of which two individuals from around the world you choose to compare. Thus, by DNA analysis, we humans are truly part of one family. This remarkably low genetic diversity distinguishes us from most other species on the planet, where the amount of DNA diversity is ten or sometimes even fifty times greater than our own.

low level of genetic diversity within our species.

Population geneticists, whose discipline involves the use of mathematical tools to reconstruct the history of populations of animals, plants, or bacteria, look at these facts about the human genome and conclude that they point to all members of our species having descended from a common set of founders, approximately 10,000 in number, who lived about 100,000 to 150,000 years ago. This information fits well with the fossil record, which in turn places the location of those founding ancestors most likely in East Africa.

If one picks the coding region of a human gene (that is, the part that contains the instructions for a protein), and uses that for the search, there will nearly always be a highly significant match to the genomes of other mammals. Many genes will also show discernible but imperfect matches to fish. Some will even find matches to the genomes of simpler organisms such as fruit flies and roundworms. In some particularly striking examples, the similarity will extend all the way down to genes in yeast and even to bacteria.

If, on the other hand, one chooses a bit of human DNA that lies between genes, then the likelihood of being able to find a similar sequence in the genomes of other distantly related organisms decreases. It does not disappear entirely; with careful computer searching, about half of all such fragments can be aligned with other mammalian genomes, and almost all of them align nicely with the DNA of other nonhuman primates.

What does all this mean? At two different levels, it provides powerful support for Darwin’s theory of evolution, that is, descent from a common ancestor with natural selection operating on randomly occurring variations. At the level of the genome as a whole, a computer can construct a tree of life based solely upon the similarities of the DNA sequences of multiple organisms. The result is shown in Figure 5.1. Bear in mind that this analysis does not utilize any information from the fossil record, or from anatomic observations of current life forms. Yet its similarity to conclusions drawn from studies of comparative anatomy, both of existent organisms and of fossilized remains, is striking.

Second, within the genome, Darwin’s theory predicts that mutations that do not affect function (namely, those located in “junk DNA”) will accumulate steadily over time. Mutations in the coding region of genes, however, are expected to be observed less frequently, since most of these will be deleterious, and only a rare such event will provide a selective advantage and be retained during the evolutionary process. That is exactly what is observed.

We can now see that the variation he postulated is supported by naturally occurring mutations in DNA. These are estimated to occur at a rate of about one error every 100 million base pairs per generation.

(That means, by the way, that since we all have two genomes of 3 billion base pairs each, one from our mother and one from our father, we all have roughly sixty new mutations that were not present in either of our parents.) Most of those mutations occur in parts of the genome that are not essential, and therefore they have little or no consequence. The ones that fall in the more vulnerable parts of the genome are generally harmful, and are thus rapidly culled out of the population because they reduce reproductive fitness.