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The Koala's Tale

For those who are unconvinced that endogenous retroviruses  derive from exogenous retroviruses. 
(Short jargon section at the bottom.)

Dr Jon Hanger with a friend.

Dr Jon Hanger worked as a vet at the Dreamworld theme park in Queensland Australia where a large number of koalas were dying of cancers. Retroviruses are often the cause of outbreaks of cancers like this.

Testing 200 captive and wild animals revealed that every one of them showed signs of a previously unknown retrovirus. It was named KoRV, standing for Koala RetroVirus.

KoRV DNA was then found in koala sperm. This meant that KoRV existed in both exogenous and endogenous forms. But certain isolated populations of koalas show no signs of KoRV and KoRV’s close similarity to gibbon ape leukemia virus (GALV) strongly suggests that the exogenous GALV jumped species to infect koalas. This means that endogenous KoRV was not originally “designed” into the koala’s DNA, but is an exogenous retrovirus that is in the process of becoming endogenized.

Moreover, endogenous KoRVs have been found in large numbers in multiple locations in the DNA of koalas.

Of 39 distinct KoRV proviral loci examined in a sire–dam–progeny triad, all proved to be vertically transmitted and endogenous; none was exogenous. Of the 39 endogenous KoRVs (enKoRVs), only one was present in the genomes of both the sire and the dam, suggesting that, at this early stage in the retroviral invasion of a host germ line, very large numbers of ERVs have proliferated at very low frequencies in the koala population. (Proliferation of Endogenous Retroviruses in the Early Stages of a Host Germ Line Invasion)

In other words, the progeny had inherited copies of KoRV in 39 different locations in its DNA. All of these corresponded to an ERV in one parent or the other, but only one of them was common to all three. The remaining 38 were in one parent, or the other, but not both. Proof that these were not “designed” into the koala genome, but acquired, either by direct endogenization, or by endogenization in an ancestor.

Other studies have found as much as 165 copies of KoRV per cell in some individuals. It appears that this retrovirus is capable of integrating into germ-line DNA in multiple locations, in large numbers.
  • Retrovirus - a virus that replicates by integrating a DNA version of its genome into the DNA of the cells of a host organism, inducing the host to make more viruses.
  • Exogenous retrovirus (or retroviral virion) - a (retro)viral particle capable of infecting cells.
  • Endogenous retrovirus (or ERV) - the DNA version of a retrovirus that has integrated into the DNA of a germ-line cell and has become heritable.
  • Endogenization - the process by which a virus becomes endogenous.


  1. But but, God designed the koala genome to do.Natural Genetic Engineering on itself! So the koala cells genetically engineered the endogenous retrovirus into themselves, and knew just where to insert them. And how could the genome be so amazing that it engineers itself? It must be intelligently designed!

    /down the rabbit hole

    1. :)


  2. I have to believe you're missing the point about ID. Let me give am analogy. Some one writes a very sophisticated software program, someone else writes a program to degrade it. The second program is able to use the original top producer copies of itself and distribute them to other machines and car them to repeat the cycle. This does not prove that the original program, let alone the computer running it, or the communication channels, came about by blind unguided chance. But that is exactly what you're claiming. Sorry, not buying it. Kerry Petersen

    1. I have removed your other comments, Kerry, because they were identical to this one. Endogenous retroviruses are clearly the inherited remains of retroviral integrations into germ-line DNA. Take a look at

  3. The problem, I think, is that you can't imagine a scenario where a Creator might create a virus that would be helpful in one context and harmful when removed from that context. It is easily within the ability of our Creator to do, and you have not demonstrated why He would never choose to do it. Death is by design of God. Disease is by design. Even if it were by chance, winning the debate helps nothing. Your argument is meaningless.

    1. If anything and everything is a "design of God", then that is an unfalsifiable hypothesis, and as such, is of no interest to science. Further, if God purposely introduced false and unnecessary evidence, appearing, to any honest and unprejudiced observer, to be solid evidence of common descent, then what you are saying is that this God is a liar and a deceiver. That strikes me as blasphemous.

    2. «Death is by design of God. Disease is by design.» That seems kind of blasphemous, too, at least for a creationist.