Endogenous Retroviral Insertions: Not Proof of Man-Monkey Kindred

[Punchy]

If endogenous retroviral insertions and other non-coding DNA are functional rather than vestigial, this should be considered evidence for design rather than evolution. ERV's were once the "magic bullet" that I used in arguing for common descent. But if humans are created in the image of God, it should be expected that most, if not all, of our DNA was designed for a purpose rather than appearing by accident.

New research continues to reveal the functional importance of the junk DNA sequences known as endogenous retroviruses (ERVs). This most recent work demonstrates that ERVs play a key role in the reproduction of mammals by controlling the development of the placenta. Evolutionary biologists maintain that because junk DNA is an imperfection, it provides incontrovertible evidence for evolution. Yet once again biochemists have concluded that junk DNA actually has function. The growing recognition of the functional importance of junk DNA undermines one of evolution’s best arguments and suggests that careful planning by an intelligent Designer, rather than undirected, random biochemical events, shaped the genomes of organisms.
http://www.reasons.org/resources/tnrtb/200611.shtml

Developmental Biology
Endogenous retroviruses regulate periimplantation placental growth and differentiation

( development | placenta | sheep | trophectoderm )
Kathrin A. Dunlap *, Massimo Palmarini , Mariana Varela , Robert C. Burghardt , Kanako Hayashi *, Jennifer L. Farmer *, and Thomas E. Spencer *

*Center for Animal Biotechnology and Genomics, Department of Animal Science, and Image Analysis Laboratory, Department of Veterinary Integrative Biosciences, Texas A&M University, College Station, TX 77843; and Institute of Comparative Medicine, University of Glasgow Veterinary School, Glasgow G61 1QH, United Kingdom


Edited by George E. Seidel, Jr., Colorado State University, Fort Collins, CO, and approved August 8, 2006 (received for review May 10, 2006)

Endogenous retroviruses (ERVs) are fixed and abundant in the genomes of vertebrates. Circumstantial evidence suggests that ERVs play a role in mammalian reproduction, particularly placental morphogenesis, because intact ERV envelope genes were found to be expressed in the syncytiotrophoblasts of human and mouse placenta and to elicit fusion of cells in vitro. We report here in vivo and in vitro experiments finding that the envelope of a particular class of ERVs of sheep, endogenous Jaagsiekte sheep retroviruses (enJSRVs), regulates trophectoderm growth and differentiation in the periimplantation conceptus (embryo/fetus and associated extraembryonic membranes). The enJSRV envelope gene is expressed in the trophectoderm of the elongating ovine conceptus after day 12 of pregnancy. Loss-of-function experiments were conducted in utero by injecting morpholino antisense oligonucleotides on day 8 of pregnancy that blocked enJSRV envelope protein production in the conceptus trophectoderm. This approach retarded trophectoderm outgrowth during conceptus elongation and inhibited trophoblast giant binucleate cell differentiation as observed on day 16. Pregnancy loss was observed by day 20 in sheep receiving morpholino antisense oligonucleotides. In vitro inhibition of the enJSRV envelope reduced the proliferation of mononuclear trophectoderm cells isolated from day 15 conceptuses. Consequently, these results demonstrate that the enJSRV envelope regulates trophectoderm growth and differentiation in the periimplantation ovine conceptus. This work supports the hypothesis that ERVs play fundamental roles in placental morphogenesis and mammalian reproduction.
http://www.pnas.org/cgi/content/abstract/0603836103v1

This serves as yet another example of how the presupposition of naturalism can hurt rather than help scientific research. If we were to allow for the possibility of design, we'd pay closer attention to how organs and DNA that appear to be nonfunctional actually serve a valuable purpose. In anthropology, we learned that there is no such thing as human vestigial organs, only organs that were once incorrectly understood. Today, we are beginning to realize that there is no such thing as "junk" DNA.

Evolutionary biologists maintain that the pseudogenes, SINEs, and endogenous retroviruses shared among humans and the great apes provide persuasive evidence that these primates arose from a common lineage. The crux of this argument rests on the supposition that these classes of noncoding DNA lack function and arose through random biochemical events. For evolutionary biologists, it makes little sense to attribute "junk" DNA to the Creator...

As researchers continue to uncover function for pseudogenes, it becomes apparent that the evolutionary perspective on noncoding DNA as junk has thwarted scientific advance. In spring of 2004 a research team discovered a new class of antifreeze proteins in fish. This function allows fish to live in subfreezing environments. However, researchers failed to recognize this new type of antifreeze protein for nearly 30 years because they had assumed its gene was a pseudogene. Only after researchers realized that the previously identified antifreeze proteins were insufficient for fish to survive in icy polar waters were they motivated to search for additional antifreeze molecules.

The discovery that some pseudogenes are actually functional means the evolutionary paradigm no longer offers the only viable explanation for their existence. Critical pseudogene activity in the cell makes an equally plausible case that the Creator intentionally incorporated this class of DNA into the genomes of humans, chimpanzees, and other organisms for reasons the scientific community is only beginning to grasp.

(Who Was Adam? A Creation Model Approach to the Origin of Man, Fazale Raza and Hugh Ross)

Peace.

 

[Mallon]

- Shared ERVs are evidence of a common designer.
- Just because "junk DNA" is seemingly non-coding, doesn't mean that we might not one day find some function for it.

I've got the YEC bases covered.

 

[Punchy]

Who said anything about young earth creationism?

 

[Deamiter]

lol good point about YEC (the last article was co-authored by Hugh Ross if I read it right).

I don't think the point was ever that ERVs have no function. ANY mutation or insertion in our DNA will over time either become useful (and impart a survival advantage) or continue as neutral. I mean this isn't any big controversy or anything, it's just how genetics works.

The key to ERV evidence of common ancestry is that ERV insertions follow EXACTLY the nested hierarchies produced by other genetic evidence and by morphology. It's not "proof" but it's yet another line of evidence that shows where we inferred common ancestry based solely on morphology, the unique genetic markers verify the ancestral relationship.

 

[shernren]

Basically, there are two ways to go about using ERVs as evidence for evolution:

1. "Unintelligent Design" criticism - i.e., this bit of DNA is junk, so how can it be designed?
2. Genetic phylogenies independently recapitulate other phylogenies, which is more likely within an evolutionary scheme than a creationist scheme.

Now, point 2 has often been brought across as encompassing point 1 or needing it to work, but I don't think it does. They can be disentangled. What's more, when they are disentangled, the ERVs are as strong an evidence for evolution as they ever were.

(By the way, if ERV genes can be co-opted by the mammalian genome and mutated to facilitate placental morphogenesis, isn't that proof of a new function being developed for old genes right there? )

 

[Punchy]

Given our current scientific knowledge, common descent is our best explanation for ERV's. What I simply do not like is the belief that any of our DNA is "junk."

 

[Mallon]

Who said anything about young earth creationism?

Oops. Saw "ERV" and I jumped the gun. My bad.

 

[Deamiter]

Given our current scientific knowledge, common descent is our best explanation for ERV's. What I simply do not like is the belief that any of our DNA is "junk."

There's no scientist in the world that believes that non-coding DNA is worthless. Like the popular terms "Big Bang" and "Black Hole" the common meaning of the word doesn't necessarily say what you might think.

In this case, as I've said there's no scientist in the field who thinks that junk DNA is worthless. Moreover, few scientists actually use the term "junk DNA" -- it's used primarily by the media and occasionally in trying to describe non-coding DNA to an uneducated and uncaring public.

Rail against the term "junk DNA" all you like -- I've done it myself in the past (where I thought it could be addressed without throwing a thread off topic).

ERV's were once the "magic bullet" that I used in arguing for common descent. But if humans are created in the image of God, it should be expected that most, if not all, of our DNA was designed for a purpose rather than appearing by accident.

Indeed evolution makes the same prediction. Most of our DNA will be beneficial in some way -- if nothing else, non-coding DNA provides potentially future coding DNA, and as you've pointed out, non-coding DNA has been found in recent years to have secondary and tertiary function (in that it can often be removed or changed without seriously imparing the organism).

Additionally, evolution predicts that mutations like ERV insertions into non-coding regions will remain until mutated away or co-opted in some vital way.

Finally, I disagree strongly that if God created us in his image, our DNA should not appear to be affected by random mutations (or as you say accident -- a loaded term that implies the interruption of normal rational action). Evolution is no accident. Descent with modification (or evolution) is simply the best way to adapt a population to a continually changing environment. Our DNA (including evidence of our ancestors in markers like ERVs) has been actively designed through natural selection, and the element of selecting for reproductive success is anything BUT random!

We know God has designed us to be able to adapt to our environment through the random mutations that happen constantly. We then see evidence of common descent among all life. Why would you contrast "designed" with "using random mutations" when the designer could very well have used random mutations in his perfect plan for creation?

Oh, and to get back to my final point, do you really think we're physically made in God's image? Does God have a (physical) heart and hair and hands that he will physically use to hug us in heaven? Or is perhaps our creation in his image a matter of being able to choose to love and our ability to choose to reject him? If our likeness in God is not physical (as most Christians believe) then why would you conclude based on that verse that all our DNA must be useful?