Tag Archives: DNA

Genetic Identity & Chimeras

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Details of bony structures in 14-week-old fetus from an ultrasound equipment manufacturer.

If you’ve followed this blog for long, you know I am pro-life, both on religious grounds and on scientific grounds. In a recent discussion on Twitter, I made a point I have made before, that the fetus cannot be a part of the mother’s body (as many pro-abortion advocates say), partly because the fetus has different DNA from the mother. Later in the discussion, an objection was raised to this point that I hadn’t heard before, so let’s work through that today.

For those who may have been living under a rock the last 60+ years, DNA is the complex molecule Deoxyribonucleic Acid found in every living cell that stores the “blueprint” for that person. First discovered in 1869, it’s structure was finally determined in 1953, and the staggering informational content fully mapped in 2003. After that slow start, our knowledge about DNA and uses for that knowledge have increased dramatically over the years. Some of the most common uses of DNA testing include determining parentage, convicting guilty criminals (or exonerating those wrongly convicted), and identifying partial or unrecognizable remains. Essentially, these examples use DNA to verify the unique identity of individual persons. Now combine that with the well-established fact that by the time fertilization is complete (within 24 hours of the joining of sperm and oocyte), and while still only a single cell, a developing baby has DNA distinct from either parent. The obvious conclusion, biologically, is that this rapidly developing organism is not the same organism as the mother.

Now, the objection raised was that unique DNA doesn’t determine how many lives are present because of the existence of chimeras. What’s that, you ask? A chimera, outside of the mythological monster from which the name is drawn, is an organism with two (or more) distinct sets of DNA. Though not “new” in terms of existence, the first confirmation of a natural human chimera was in 1953 when a woman in England donated blood and it was found to contain two different blood types in one sample. As our knowledge of genetics has grown and DNA testing has become more commonplace, so too has observance of this phenomenon. for instance, a woman needed a kidney transplant in 1998, but when her 3 sons were tested as potential donors, 2 of them were determined, based on DNA, not to be her biological sons, even though she had given birth to them. Then in 2003, a woman in Washington filed for welfare benefits for her children and was denied, with accusations of welfare fraud pending, because her 2 children were determined not to be hers. A 3rd child was born while this was being investigated, so that birth and an immediate DNA test of both mother and child were witnessed by an officer of the state. Again, the DNA test showed different parentage for the child just born. What happened in each of these cases? Each of these 3 women had been twins. The Englishwoman in 1953 had a twin brother who had died shortly after birth. Cells had been shared between the two early in the pregnancy. The other 2 women were both the result of fused embryos, or a “vanishing twin”. Two oocytes had been fertilized by two sperm, resulting in twin zygotes. Early in the pregnancy, however, the two zygotes merged into one. Because they were separate zygotes, they each had different DNA. However, because this occurs very early in development, the zygote is still a collection of totipotent cells (meaning each cell at this stage can still become any cell in the human body, i.e. they have not differentiated into their separate lines of specialized cells for organ generation). When the twin zygotes (call them A & B) fused together, some of the cell from twin A went on to form various body parts like the skin cells inside the cheek where DNA samples are often taken. Cells from twin B went on to form other body parts such as the ovaries that would be responsible for producing children “not her own”. A third scenario, Fetal Microchimerism, or FMc, is much more common and is when cells from the blood of the fetus and/or mother get through the placental barrier to reside in the other person. Cells from their children have been found in the bodies of autopsied women many years after their pregnancies.

Based on these observed cases, we know that a person can have multiple DNA. But does the existence of chimeras refute the idea that the developing baby is a unique individual distinct from the mother? I don’t think so. After all, when a patient receives an organ transplant, the donated organ will have the donor’s DNA rather than that of the recipient; but nobody considers the donor and recipient to be part of the same body. Furthermore, even though the person may have 2 sets of DNA in their body, the transplanted organ is only one organ, and cannot become anything more. A zygote, on the other hand, is capable of developing into a mature human, and is, in fact, directing much of the pregnancy. The case of cells passing between twins in utero, as in the 1953 English case, is really no different than the case of organ donation between adults. The case of fused zygotes is more extreme in that all of the “donor” has been passed to the recipient, but the concept of a donor providing some portion of a recipient’s organs still applies. Because the transfer of genetic information occurs at such an early stage, it’s impossible to know which organs formed from donor and which from recipient without some kind of comprehensive test that is not practical at this point, but it’s important to remember that neither zygote had the same DNA as the mother, so the resulting chimera is still not part of the mother’s body no matter how you look at it. As far as fetal microchimerism, we are only talking about a few individual cells from a genetically unique human (i.e. the baby) passing through the barrier that normally separates the baby’s blood from the mother’s, and residing in the body of another genetically unique human (i.e. the mother). The fact that a few of the baby’s cells migrate into the mother’s body (and vice versa) no more make the baby part of her body than an organ donor’s cells inside a recipient’s body makes the donor part of the recipient.

Does the chimeric objection succeed? No. Even with individual persons not necessarily being limited to only one DNA in their body, the baby is at all stages of development a separate, self-contained organism temporarily residing in the mother for nourishment and protective environment, and not a “part” of her that just has different DNA. All cases of chimerism, both natural and artificially induced, come about from the involvement to one degree or another of a second, genetically distinct organism. The different DNA confirms this and actually bolsters our understanding of a baby as a genetically unique individual from conception.

Further reading: “The Human Chimera: Legal Problems Arising From Individuals with Multiple Types of DNA“, by Robert Russell Granzen, Seton Hall Law School, 2014, was a thorough and interesting read on the matter.

Reading License Plates

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What a random group of letters & numbers….

Not all countries allow this, but here in America, we have the phenomenon of the “vanity plate” – the ability to pay a fee and get personalized license plates for your vehicle. Having a long commute to work each day, I get to see a lot of license plates, many of them personalized. What do personalized license plates have to do with apologetics? Let’s work through that today.

It’s always impressive how creatively people can convey a message with 7 characters. Some are quite amusing. Of course there’s sports cars with plates like “BAD BOY”, or “2FAST4U” and so on. There’s the pilot that gets the plate “LUV2FLY”, or the veterinarian that gets “PETDOC”. Others leave you scratching your head, thinking, “That must be an inside joke or something.” Some of the more creative tricks of personalized plates are the use of numbers that look like letters (i.e. 5 for S), or letters and numbers that look like other letters when viewed upside down or backwards (i.e. 3 for E, W for M, and so on). Those tactics can make it a little more challenging to figure out the significance of the plate. But then I have to ask myself when I see a personalized plate that I can’t decipher, what makes me think it means anything? I didn’t get the point of the characters they picked, but I assumed my comprehension was the issue, and not that there was no message to comprehend. Why is that? It’s because I know license plates in my state conform to a particular pattern of letters and numbers (3 numbers, a space, and 3 letters, sequentially assigned by the state), and when a particular plate doesn’t conform to that predefined pattern, that’s indicative of intent, or purpose, behind the arrangement. I don’t have to know the car owner’s intent in order to recognize that there was intent behind the characters picked, and that his personalized license plate is not the result of random assignment. Likewise, we don’t have to know God’s intent in creation to recognize the presence of purposeful choices that require an intelligent agent to make them. But while seeing a designed message in a customized license plate may seem intuitive, are we justified in applying that reasoning to things like nature? What about false positives – seeing design where there is none? Let’s look at how we eliminate chance and how we confirm design now.

An event conforming to an independent predefined pattern (like recognized words in English) is one way to eliminate randomness as a reasonable explanation for an event. Stephen Meyer, in his book, Signature in the Cell, uses the example of a gambler named Slick who keeps winning at the roulette wheel – 100 times in a row – by betting on Red 16.[1] Could his amazing winning streak simply be the result of chance? It’s possible, although to call it astronomical odds would be an understatement. But why would the casino, and any reasonable person, think this wasn’t simply chance, but either a cheating player or a mechanical malfunction? The consistently beneficial results make it less and less reasonable as the streak continues, and the pattern negates the chance hypothesis. While chance is eliminated, design isn’t confirmed yet; the pattern may match with physical necessity due to an unbalanced wheel that makes the ball always land in Red 16. Slick could just be just taking advantage of a pattern he noticed. Meyer then asks about a different case, where Slick bets on different numbers each time, but still wins 100 times in a row. The ball isn’t landing on Red 16 every time now, so physical necessity (like a defect in the roulette wheel) doesn’t seem to be the culprit. And yet we still instinctively reject that this is simply chance, and think Slick is cheating, or “designing” his winning streak. Why? Because the seemingly random pattern of results matches the independent pattern of Slick’s bets. These are “functionally significant” results that accomplish something – they advance the goal of him winning lots of money! And achieving a goal is the very heart of design. Both cases reject chance based on the events matching a pattern, but the second case reasonably infers intelligent design behind the pattern.

In that example, the predefined pattern (winning each spin of a roulette wheel) is framed positively. But the same applies as a negative association: when a result doesn’t conform to the known pattern that it should conform to, such as the “123 ABC” format of license plates in my state,  then we can know that something else is going on. Based on my knowledge that government-issued license plates conform to specific patterns of characters unless a person pays extra to make a non-random assignment, I can reasonably infer that a plate not conforming to those set patterns was intentional, at the least. The fact that someone paid extra for their non-random plate makes it unlikely that they then picked a combination of letters and numbers that had no meaning to them. Now, when I see things such as coded information in DNA, I can reasonably reject chance or physical necessity as an explanation. The arrangement of bases in a strand of DNA is highly contingent, yet arranged extremely specifically over a very long sequence to produce highly functional information. Now, if I’m justified in thinking 7 letters and numbers on a license plate have been deliberately arranged to convey a message, why would I not recognize the message conveyed by the information overload of over 3 billion bases carefully arranged like letters in words to store the massive amounts of information that make up our bodies? And where does that message point me? To the design hypothesis, which requires an intelligent agent beyond any human (or any physical entity, for that matter). It points me to God. Where do you look for the author of that message? Till next time, blessings on you.

[1] Stephen C. Meyer, Signature in the Cell: DNA & the Evidence for Intelligent Design, (NY: HarperOne, 2009), chapters 8 & 16.

Divine Design (The Teleological Argument)

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London Museum Roof SmallWe’ve been looking at different explanations for the existence of God, and this week we have one that resonates with me as an engineer: the teleological argument, or argument from design comes from the Greek word “telos” meaning end purpose or goal. The argument is as follows:
Premise 1: Every design has a designer.
Premise 2: The universe was designed.
Conclusion: Therefore, the universe had a Designer.

Now let’s unpack those tidy little premises. Does every design have to have a designer? Design can be defined as: “a specification of an object (or process), manifested by an agent, intended to accomplish goals, in a particular environment, using a set of primitive components, satisfying a set of requirements, subject to constraints.” Though a bit dry, this actually describes my daily tasks as an engineer pretty well. But notice that design is defined as being “manifested by an agent”. It appears that designs have designers by definition. But even without the word “agent” in there, we can see that design requires intent – an end purpose, a goal. But goals require consciousness to make choices between alternatives. Processes like natural selection, unguided by conscious agents, can only “choose” alternatives that confer immediate advantage. For example, chess moves that sacrifice an immediate advantage for a long-term gain are not possible without the foresight of design. Chance and physical necessity also can’t explain evidence of design such as intent. Therefore, the indication of long-range intent is confirmation of a designer.

The second premise is perhaps more controversial. But let’s follow the evidence along 3 lines: terrestrial, cosmic, and biological design. First, many parameters on earth appear to be fine-tuned for life to exist, and not just any life, but large, complex life. Things like atmospheric transparency, oxygen content, the polarity of the water molecule, and the temperature of max density of water, among a variety of other dispersed parameters, appear to all be set to values in very narrow ranges that allow for our level of life to exist (and flourish). Second, although these values all fall in narrow ranges, we find in the universe parameters that are even more precisely balanced in favor of life. But these parameters are fine-tuned not just for life anywhere in the universe, but specifically for life on earth. Properties such as the speed of light, the ratio of proton to electron mass, the mass density, expansion rate, homogeneity, and entropy level of the universe, the  uniformity of radiation, the values of the four fundamental forces (gravity, electromagnetism, and the strong and weak nuclear forces), and the location of earth both in our galaxy and the Milky Way’s location in the universe, are some of the roughly 100 interdependent parameters that have to be what they are for us to exist.[1] Interestingly, we also happen to be in a unique position in the universe to even be able to see the evidence of this design.

Third, the structure and information content of DNA points to extremely information-centric design. Four DNA bases are the optimum number for speed of replication.[2] From a data storage standpoint, the 4 letter “alphabet” and 3 letter “words” used by DNA for synthesizing proteins are the most efficient system possible in terms of minimizing space requirements in the cell, simplifying encoding/decoding of the data, and maximizing redundancy for error checking.[3] DNA exhibits nested encoding where the same stored data is used to convey meaningful information when read one way, and different meaningful information when read a different way.[4] To understand the significance of this coding accomplishment, try writing a book that tells one story when read in order, and a different, but still intelligible, story when reading only every third word. This increases the storage capacity of DNA immensely. Even so, DNA does not have all of the information needed to assemble an organism in it.[5] Some of the information is stored outside the DNA, which leads to a chicken-and-egg problem of how the cell is built by plans stored in the DNA, but with instructions stored in the cell that’s being built using the DNA plans. Our planet, our universe, and even our own bodies appear to all show signs of design, making the second premise true.

If these 2 premises are true, then the conclusion is true that the universe had to have a designer. What characteristics could we infer about this designer from the conclusion?

  • Intelligence – far beyond that of any human designer to understand complex and interdependent “systems of systems” comprising the universe.
  • Foreknowledge – far beyond any human ability to anticipate highly complex interactions and plan for those contingencies.
  • Power – far beyond any human capacity to alter our surroundings (we celebrate when we figure out how to copy something in nature successfully; making all of nature from scratch is in a whole other league of accomplishment).
  • Intemporality and immateriality – no design precedes it’s designer. If the universe (and therefore all of space and time) had a designer, then that designer had to precede the universe. Therefore the designer would have to exist outside of space and time.
  • Benevolence – It’s relatively easy to imagine many ways our universe could be organized that would result in life being a much harder, more miserable, existence for us. Also, the fact of our unique position in the universe to be able to see so much of it could be an example of a deliberately placed trail leading us back to this designer.

These correspond well with the omniscient, omnipotent, omnipresent, eternal, loving God of the Christian Bible. So then, how do we respond to this? We could a) accept the evidence left for us by this God, and seek after Him, b) deny the evidence having honest doubts, but attempt to offer an alternative that explains the evidence as well, or c) simply refuse to consider the evidence. Please, don’t be content with this last option.

[1] Hugh Ross, “Fine Tuning for Life in the Universe”, http://www.reasons.org/articles/fine-tuning-for-life-in-the-universe, accessed 2014/08/03.
[2] “Why is the Number of DNA Bases 4?”, by Bo Deng, Dept. of Mathematics, University of Nebraska – Lincoln. Published in the 2006 Bulletin of Mathematical Biology.
[3] Werner Gitt, Without Excuse (Atlanta: Creation Book Publishers, 2011), p. 162-166.
[4] Stephen Meyer, Signature in the Cell (New York: Harper Collins, 2009), p. 466.
[5]  ibid., p. 473-474.

Alphabet Soup

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DNA_animation

I explained a few weeks ago how any kind of observed design actually requires a designer, by definition. If we correctly observe design, we can reasonably infer the existence of a designer. But how do we know we’ve correctly observed intentional design?  We don’t want false positives or false negatives (while thinking you were healthy when you had cancer could be fatal, mistakenly thinking you had cancer when you don’t, and having an unnecessary amputation isn’t desirable either). And so the atheist is often concerned that we Christians are falsely attributing intentional design by God to naturalistic processes. Let me start by saying I appreciate those concerns. So today, let’s look at the evidence for intentional design in nature in the form of information.

The presence of information is a key part of confirming design because true information is always the result of intelligence. Waves makings ripples in the sand are an unguided process that may generate patterns, but not information. On the other hand, someone writing their name in the sand has guided the movement of the sand so as to convey data (their name) using symbols (letters) arranged in a non-random order (J-O-H-N) with a goal (for others to know that John was there).  If we walk down that beach later and find that name in the sand, we recognize this was not the work of the waves, but rather an intelligent agent, because codes (i.e. the English language) are not generated by physical-chemical processes alone. Meaning is conveyed by the willful choice of certain letters to form certain words in a certain order, but natural processes do not possess a will – only intelligent agents do. This then takes us back to the causal agent required of design.

If I hand you a piece of paper that has been moved at a constant speed under an eyedropper filled with ink, will the series of evenly spaced dots provide you any information? The repetitive pattern of dots are arranged as they are out of necessity. What if the ink drops were splattered randomly on the paper where there was no pattern whatsoever? The first is highly specified (identical spacing and size of dots) but repetitive and not complex. The 2nd is complex (in that it would be very difficult to intentionally reproduce it), but completely unspecified. Either way, no useful information is conveyed. But what if the ink drops were from an inkjet printer that was plotting a set of framing plans for a skyscraper? Has information been conveyed? Certainly, but how can we know that? The symbols on the paper exhibit specified complexity. They are a product of neither chance nor necessity. They also have a clear purpose: If you follow the instructions presented, with the materials specified, in the order prescribed, you will have successfully constructed a tall building. These characteristics can differentiate legitimate information from repetitive patterns and random noise.

Now let’s apply what we know about information to DNA.  Deoxyribonucleic acid is composed of 4 bases (Guanine, Adenine, Cytosine, and Thymine) attached to the famous double helix backbones of sugars and phosphates. These bases match up in pairs (G&C, A&T).  One DNA molecule can have 220 million of these base pairings. The entire human genome, the transcript of all the base pairings in all of human DNA, is 3.4 billion units.  Printed out in small font, this takes over 100 volumes of 1,000 pages each. While DNA is still mind-blowing 50+ years after it was discovered, and we’ve still only scratched the surface of understanding it, does assigning letters to these bases and filling books with them make this a language? Are these letter sequences conveying information? Actually, the ability of DNA to store and transmit information has not been lost on scientists. In 2012-13, 2 different groups managed to encode text, pictures, and audio data into DNA’s code, synthesize actual DNA from it, then sequence that DNA to get the original data back with 100% accuracy.  In fact, DNA makes for a far more stable data storage medium than our current typical magnetic disks. It’s also estimated that one cup of DNA could store 100 million hours of hi-def video[1].

Let’s compare this 4-letter “alphabet” to some other alphanumeric codes. Consider this: our common number system is called Base 10 because it uses the ten digits 0-9. Our computers use “binary”, a Base 2 system that only uses the numbers 0 and 1, because these can represent physical states of on and off. Hexadecimal (Base 16) has been used in computers to reduce storage requirements. It uses the digits 0-9, then adds the letters A-F. In this way, you can count to 15 with only 1 digit (F) compared to the 4 digits needed in binary (1111). The English alphabet that I’m using to communicate right now is a sort of Base 26 code. You have 26 symbols to use for each character, and if that’s not enough to convey an idea, then you need to keep adding characters to form words, stringing those into sentences, paragraphs, books, and rambling blogs…. Knowing how base systems work, what do we see when we look at DNA? We see a Base 4 code for conveying information. Interestingly, a 2006 paper in the Bulletin of Mathematical Biology asked the question of why DNA is a Base 4 code and not a binary code, or Base 6, Base 8, etc, and concluded that Base 4 actually maximizes the rate of replication over every other option.[2] Dr. Werner Gitt looked at DNA from a data storage standpoint and concluded that the 4 letter “alphabet” and 3 letter “words” (codons) used by DNA for synthesizing proteins were the most efficient system possible in terms of minimizing space requirements in the cell, simplifying encoding/decoding of the data, and maximizing redundancy for error checking[3]. So the framework for efficiently storing and communicating information is there, but is there actually information there? Like the set of framing plans, if you follow the data found in human DNA you will end up with a human. In fact, this is carried out every time a baby is conceived as a new human is constructed from the plans found in its DNA.  The data found therein is extremely specific, highly complex, and has intent or end-purpose. Therefore, it does indeed seem to be true information, requiring an intelligent source, and providing an additional jigsaw piece in our design puzzle.

1. http://phys.org/news/2013-01-dna-storage-million-hours-hd.html
2. “Why is the Number of DNA Bases 4?”, by Bo Deng, Dept. of Mathematics, University of Nebraska – Lincoln. Published in the 2006 Bulletin of Mathematical Biology.
3. “Without Excuse”, by Werner Gitt, PhD, 2011.