Butterfly mimicry v. Darwin

Butterfly Mimicry: A "Huge" Problem for Evolutionary Biology
Casey Luskin


Can Darwinian evolution explain the complex coloration patterns found in insects that led to biomimicry? According to an article published late last year in BioScience, Darwinian evolution faces "problems" that are "huge" when trying to account for the origin of biomimicry in butterflies:

The balance of Dazzled and Deceived focuses on the genetics and development of mimetic patterns, as revealed mostly through work with butterflies. The problems here are huge for evolutionary biologists. How does natural selection build a complex organism with all its integrated parts through fixation of random mutations? Butterfly mimicry has been a classic arena in which to tackle this problem precisely because the gambit is so obvious: To be a good mimic of another species requires many pattern elements of bars, lines, colors, and even wing shapes to change at once. Moreover, how can this process produce females that are perfect mimics and males that look nothing of the sort within a single species? These genetic requirements are seemingly at odds with our understanding of gradual evolutionary change and genes of small effect.
(Edmund D. Brodie III, "Butterflies and Battleships," a review of Dazzled and Deceived: Mimicry and Camouflage by Peter Forbes (Yale University Press, 2009)," BioScience, Vol. 60(10):850-851 (November, 2010).)

Perhaps it's appropriate that Brodie states that "dogma can be dangerous." Or maybe not, given that his explanation for the evolutionary origin of mimicry is nothing but vague:
Forbes takes us through the emergence of E. B. Ford's school of ecological genetics and the basement-made butterfly crosses that eventually began to illuminate the problem of linked-gene complexes ("supergenes"), sex-linked inheritance, and modifier genes. The answers to the mimicry paradox, preliminary as they are still, inform modern evolutionary-developmental studies in all species and have launched the current effort to map a number of butterfly genomes. These genomic excursions promise to uncover the genetic architecture of mimetic patterns in a variety of species and in doing so uncover the fundamental basis of adaptation and speciation.

If our understanding of the genetic basis for these mimetic patterns is still "preliminary," then it would seem we're even further away from understanding how they evolved. Apparently these "problems" that are "huge for evolutionary biologists" are not going away anytime soon.

on competing models of human ancestry.

In BIO-Complexity, a New Model for Human Ancestry
Ann Gauger 

In 2012 at a scientific conference I met a Swedish population geneticist named Ola Hössjer. He and I sat down in the lobby of the hotel where we were staying to discuss what kind of population genetics model might be possible to test whether humanity could have come from a single first pair of humans. The motivation for doing so was the repeated challenge from other population geneticists claiming that we humans had to come from a population of thousands, not just two. He and I both knew the assumptions that had to go into the models such population geneticists constructed, and wondered if different starting assumptions would yield different results.

Population genetics is a field that uses math to model how genes and mutations are distributed in populations and how that distribution changes over time. It can be used to model our ancestry, to reconstruct our genetic history as a population as a whole, or as smaller subgroupings such European, Asian, African, etc., or even tribes within a larger grouping. The standard population genetics models that reconstruct ancestral history work backward by a process of coalescence to a starting point where everything is identical -- everything starts out the same, with one set of chromosomes, and diverges from there by the accumulation of mutations, and the processes of recombination, genetic drift, and natural selection.

Back in that hotel lobby, Ola and I quickly came up with a list of variables that would need to be accounted for in any model, things that are unknown aspects of the history of our origin, and we talked about the computational problems of any forward-looking model, one that goes from two individuals at the start to something like the present population. To keep track of all the variables and to trace the possible genetic changes quickly becomes computationally too intense to go very far. I personally thought such a model was intractable and beyond anyone's ability to build. Was I wrong!

A little over a year ago Ola presented a model to our now co-author Colin Reeves and me that took all those variables we had discussed in Copenhagen into account. It is the most comprehensive population genetics model I have seen anywhere -- it's a brilliant piece of work. Ola found a way to solve the problem of the explosive nature of forward-directed models I mentioned above. He uses the same coalescent technique of the standard models to reconstruct an ancestral tree from a few thousand individuals in the present time, going backward to a starting point of two. His model then reverses the process by going forward in time, using the tree as a framework to keep track of genetic changes.

The model is general enough that it can be of use to any geneticist to test the effects on genetic diversity of processes such as migration, age structure, mating behavior, and other aspects of population dynamics and demography.

The key assumption that distinguishes our model from the standard ones is that we assume that the first pair started out with heterogeneous chromosomes -- four distinct sets, two sets for each individual. The standard population genetics models work backward assuming everything starts from a single point. We are proposing that things started out different, not the same, with diversity present from the beginning in the genomes of the starting first pair.

We still need to code this model, which is a work in progress being done by Colin Reeves, and we hope others as well, as it is a massive project, and will require time and resources. But when it's completed, we will be able to test the hypothesis that we can recreate modern genetic diversity starting from an original pair with original genetic diversity. Should we be able to demonstrate this, there will be two competing models for human origins, one that says we came from a population of thousands, and ours that says we came from a population of two. We will see which best fits the available data and yields the most insight.


The model has now been published in the journal BIO-Complexity, in two parts, the first being a general introduction to population genetics and the rationale for the model, and the second being the model itself. My hope is that this model will be the catalyst for much research and discussion, on both sides.

The making of an antidarwinian bomb thrower.

Behe -- The Makings of a Revolutionary
David Klinghoffer





It's a pleasing coincidence that in the new documentary Revolutionary we look back to the origins of Michael Behe's insights on irreducible complexity, published twenty years ago in Darwin's Black Box, just as we look forward to the results of the potentially historic Royal Society meeting in London, underway at this moment.

No one scheduled to speak there is an advocate of intelligent design, but the scientific critique of Darwinism that Dr. Behe was crucial in launching has that meeting, at least in part, as its fruit.

Would such a conference, raising basic questions about the adequacy of neo-Darwinism, be happening now if it weren't for Behe, and before him Denton and Johnson? There's reason to wonder.

In a new brief video, above, Behe discusses the roots of his thinking, including a Science article that warned professors to warn their students against Phil Johnson's book Darwin on Trial, prompting a stinging missive from Behe that Science published in a subsequent issue.


Stephen Meyer and Paul Nelson recall their responses to meeting and working with Behe back in the early Nineties, as the revolution was just getting under way. Not that long ago, but how things have changed! Get your copy of Revolutionary, on DVD or Blu-ray, today.