Interview with Judge John E. Jones III

The journal PLoS Genetics has published a wonderful interview with Judge John E. Jones III. A conservative federal judge in the US District Court for the Middle District of Pennsylvania, Judge Jones was recommended for his current position by PA senator Rick Santorum and appointed to the bench by President George W. Bush in 2002. Judge Jones ruled for the plaintiffs in Kitzmiller versus Dover Area School District striking down a school board policy exposing students to intelligent design creationism in the public classroom.

In the PLoS Genetics interview Judge Jones is asked about his own personal views on creationism and evolution. After saying that as a judge he can review a case independent of his personal views he adds,

"I am a person of faith. I'm certainly not an atheist or an agnostic and I see some divine force somewhere. That said, having had a pretty good education, a great liberal arts education at Dickinson College, I must say that I never had any substantial doubts about evolution generally. I had forgotten, admittedly, a lot of what I had learned about evolution back in college. Moreover, a lot had happened since the '70s, so my understanding was rudimentary. But I never had a crisis of confidence about evolution or a reason to doubt that it constituted a valid theory and good science."

Brown University biologist Ken Miller was an expert witness in the trail and recently gave a wonderful lecture on evolution and intelligent design as part of the Cincinnati Museum Center's Dury Science Lecture Series. Here's what Judge Jones had to say about Dr. Miller's testimony in the PLoS Genetics interview,

"I will always remember Ken Miller's testimony in the sense that he did A–Z evolution. And then got into intelligent design. And having laid the foundation with the description of evolution, got into why intelligent design doesn't work as science, to the point where it is predominantly a religious concept."

Contrast this with Judge Jones opinions of the expert witnesses for the defense, particularly Lehigh University professor Michael Behe,

"Another remarkable moment on the science side was Michael Behe, who was the lead witness for the defendants, and a very amiable fellow, as was Ken Miller, but unlike Miller, in my view, Professor Behe did not distinguish himself. He did not hold up well on cross-examination."

That a conservative self-proclaimed "person of faith" appointed to the bench by President Bush rules so desisively against the teaching of intelligent design creationism speaks volumes for the validity of the evolution position and the vacuity of intelligent design from a scientific and, in so much as the idea is applied to public education policy, legal stance.


Yeast goes with the FLO“Share and share alike”, so goes the old adage about equally distributing goods, even at one’s own expense. Darwin’s idea of natural selection explained evolutionary change by posing that traits spread in the population due to the benefits these traits confer on their bearers. Individuals with certain characteristics produce more offspring relative to those individuals with other characters and as a result the population as a whole takes on a different appearance. However, Darwin’s idea couldn’t explain those traits that provide benefits to others at the expense of their bearers. Sharing with others at one’s own expense is called altruism and in biology altruism remained a puzzle for over a century after Darwin.

Then come the 1960’s and William Hamilton. Hamilton said that a rare gene underlying some altruistic behavior could spread despite the cost to the bearer. But how? How could a gene that results in fewer offspring for its bearer spread in the population? Lucky for Hamilton he had an understanding of genetic inheritance that was not available to Darwin. If behavior is directed towards those individuals in the population who also harbor the same genes for altruism then the trait will spread in the population through the recipients of altruistic behavior. Rare genes for altruism would more likely spread if there were a readily observable marker of the same altruistic gene in others. Richard Dawkins popularized this idea in the 1970’s calling it the ‘green beard effect’. In a hypothetical example Dawkins imagined that genes for altruism would result in a marker, such as a green beard, along with the altruistic behavior. With this clear marker of the altruistic gene in others helpers could direct their behavior only towards those that shared the gene for altruism.

Amazingly there is good evidence for the ‘green beard effect’ in nature in several organisms, from slime molds and fire ants. Even more astonishing, there are examples where a single gene is responsible for ‘green beard’ altruism. Scott Smukalla, Marina Caldara, and Nathalie Pochet of Harvard University and their colleagues report in the latest issue of the journal Cell that they have found a ‘green beard’ gene in the budding or brewer’s yeast, Saccharomyces cerevisiae.Yeast is not only the critical component in the making alcoholic beverages but it is also a classic model system in the study of the eukaryotic cell. Yeasts are single celled organisms but wild strains of Saccharomyces cerevisiae in times of stress will aggregate into multicellular mats often called biofilms. These aggregates of cells can protect cells from antibiotics, heat and cold stress, ethanol, and other toxins. The coming together of single yeast cells into a multicellular group is called flocculation and the aggregations are known as flocs. Occurring in wild yeast in response to stress, flocculation allows the population to ride out tough times.

Typical of many organisms grown under the resource-rich and stress-free conditions of the laboratory, times are seldom that tough and many years of culture in the lab have lead to the loss of flocculation in laboratory strains. Comparing a wild, flocculent strain called EM93 with a laboratory strain, S288C, incapable of forming flocs, Smukalla and colleagues found that flocculation fell under the control of a single variable gene called FLO1. This was confirmed by activating the expression of FLO1 in normally non-flocculent S288C cells. Expression of FLO1 resulted in flocculation exactly like that observed in wild yeast. FLO1 expression creates cell membrane proteins that allow cells to recognize and adhere to other yeast cells expressing the FLO1 gene.

FLO1 in Saccharomyces cerevisiae acts like the ‘green beard’ gene predicted by Hamilton as it allows yeast cells to detect others also expressing FLO1 and form multicellular aggregates and thus provide group protection against environmental toxins. But, remember altruism by definition involves a cost to the altruist. Where is the cost? When grown under toxin free conditions and ideal temperatures yeast expressing the FLO1 gene suffer a 4-fold reduction in population growth relative to yeast cultures that do not express the FLO1 gene.

A mixed culture of FLO1 expressing and non-FLO1-expressing cells grown under conditions that lead to flocs results in flocs containing primarily FLO1 expressing cells and free cells that do not express the FLO1 gene. FLO1 is therefore a true ‘green beard’ gene as it promotes the altruistic, social trait (flocculation) and at the same time excludes participation of those cells not expressing the social trait. Requiring FLO1 for cell adhesion eliminates the spread of selfish cheaters, yeast cells that forego the cost of expressing FLO1 while times are good but also reap the benefits of flocs when times are tough.

Research on the evolution of social, altruistic traits like flocculation can shed light on one of the most important transitions in the history of life, the evolution of multicellular organisms from single celled organisms. Saccharomyces cerevisiae, social amoebae, slime molds and many social bacteria move between a single celled and a multicellular lifestyle. Like Saccharomyces cerevisiae, multicellular forms in other microorganisms are often in response to stressful environments. Very early in our own evolution the colonization of harsh environments by our single celled ancestors likely promoted the same altruistic behavior seen in many modern microorganisms today.

S SMUKALLA, M CALDARA, N POCHET, A BEAUVAIS, S GUADAGNINI, C YAN, M VINCES, A JANSEN, M PREVOST, J LATGE (2008). FLO1 Is a Variable Green Beard Gene that Drives Biofilm-like Cooperation in Budding Yeast Cell, 135 (4), 726-737 DOI: 10.1016/j.cell.2008.09.037


Ken Miller speaks at Cincinnati Museum Center

This Thursday, December 4th at 7:30pm at Cincinnati Museum Center's Union Terminal Dr. Kenneth Miller of Brown University will speak in the museum's Dury Science Lecture Series. Dr. Miller is a cell biologist and author of life sciences textbooks and popular books on the conflicts between evolution and intelligent design creationism.

A vocal proponent of evolutionary biology in the public arena Dr. Miller has been featured on the PBS series Evolution and served as an expert witness in the recent Kitzmiller v. Dover Area School Board case in US District Court of Middle Pennsylvania. Dr. Miller's testimony played a critical role in the Judge John Jones' decision which declared that the Dover school board's policy to promote intelligent design (ID) theory in public school science courses was in violation of the US Constitution's Establishment Clause because, while presented as science, "ID cannot uncouple itself from its creationist, and thus religious, antecedents".

While proving to be highly effective at exposing the deep flaws within this latest version of scientific creationism, ID theory, Dr. Miller has provided a counterpoint to creationist/ID accusations that evolution promotes atheism by being very open about his own personal beliefs in the Christian faith. Miller's highly successful popular book Finding Darwin's God was not only an effective rebuttal against ID but also a personal testimonial of a Christian scientist's ability to reconcile faith with the scientific consensus on biological evolution. His latest book, Evolution and the Battle for America's Soul, dismantles ID arguments and emphasizes the explanatory power of evolutionary biology in making sense of life's diversity.

In a dwindling economy with environmental and energy crises looming larger and innumerable challenges for the US both domestic and abroad the ability to innovate is critical in moving America forward. The launch of the Sputnik satellite in 1957 by the Soviet Union was a wake-up call for the US and spawned an increased focus in science education and research in the 1960's. The rising prominence of China and India in science and engineering is today's Sputnik and Americans need to decide if they want to continue to be leaders and producers of science innovation and technology or followers and consumers of technology provided by other nations.

Far from an esoteric issue the debate between ID creationism and evolution cuts to the heart of science education in the US. On the one side is scientific innovation and adoption of evidence based inquiry and the other is an attempt to roll back two centuries of scientific progress and judge scientific evidence on the basis of narrowly-defined, preconceived socio-religious ideology. Attending Dr. Miller's lecture at the museum center will be an excellent introduction to these critical issues in American scientific literacy and demonstrate that, contrary to what creationists would have us believe, scientific progress need not come at the expense of our religious faith. I hope to see you there.


DNA lab is coming together

The new molecular genetics lab at Cincinnati Museum Center is slowly coming together. Supported by a grant from the National Science Foundation this lab will provide the instruments needed to apply molecular genetic tools in research in ecology, evolutionary biology and molecular systematics. The centerpiece of the lab is an automated capillary electrophoresis machine, also known as an automated DNA sequencer, manufactured by Applied Biosystems. We received a new lab bench to support this valuable instrument and provide much needed workspace. We also had to run a new electrical line to supply 220V, 30A power to the sequencer. Researchers from partner institutions such as Xavier University and Thomas More College will be touring the new lab soon and start bringing in students to gain valuable skills in cutting edge molecular genetic tools. The lab is getting some attention in the community as well and a story by staff reporter James Ritchie appears in the Buisness Courier of Cincinnati.

Yesterday I ran the very first polymerase chain reaction EVER at Cincinnati Museum Center. This technique used to copy a specific region of an organism's genome is the backbone of modern molecular genetics. Our first reactions were a test run of some genetic sexing reactions amplifying a seqment of the sex-linked chromo-helicase-DNA-binding gene in Red-shouldered Hawks. This work is done in collaboration with Cheryl Dykstra to learn about growth and development of Red-shouldered Hawk nestlings in Southern Ohio.

I have high hopes for the lab. Keep checking back here and at cincyevolution for more updates on this new line of research going on in molecular ecology and systematics at Cincinnati Museum Center.


How to collect a blood sample from a bird

Genetic tools are a major part of modern comparative biology. Museums are the place where much of this sort of research occurs as museums are storehouses of the source material used in comparative genetic studies. Frozen tissue is stored in ultralow freezers or in liquid nitrogen for a variety of organisms comprise genetic resource collections or GRCs. Ideally tissue samples should be associated with a voucher specimen such as skeletal material, a stuffed skin or a pickled specimen. This allows researchers to check the identity of the tissue sample or compare genetic data with morphological data derived from the source specimen. In ornithology there is a growing trend to collect a blood or feather sample from a bird and release the bird back into the wild. A digital photo together with carefully taken morphological measurements can serve as the voucher for the blood sample. While this is not the "gold standard" way to build a bird collection it can augment traditional collecting efforts and increase numbers of samples while minimizing the effect of collecting on avian populations. Below is a video of me collecting a blood sample from a House Sparrow (Passer domesticus) caught just outside the Geier Collections and Research Center at Cincinnati Museum Center. When done properly there is no evidence of adverse effects on the bird, even though surely it is not an experience they enjoy!


New National Science Foundation funded DNA lab at CMC!

Fantasic news for zoology research and education at the Cincinnati Museum Center. We just received an award from the National Science Foundation to fund the purchase of instruments for a molecular ecology and systematics laboratory in the zoology department here at the Cincinnati Museum Center! The centerpiece of this new laboratory will be an automated capillary electrophoresis machine. This piece of equipment will allow for DNA sequencing and multilocus genotyping to be done completely in house at Cincinnati Museum Center's zoology department. Numerous projects are already planned to be conducted in the new lab covering a diverse array of topics, everything from DNA barcoding of Neotropical land snails to the population genetics of owls to amphibian conservation genetics to characterizing the genetic mating system of songbirds. The new lab will have close partners in the region including the Cincinnati Zoo, Thomas More College, Cincinnati Country Day School and Xavier University and will facilitate research, future funding opportunites and educational experiences in cutting edge life sciences techniques for high school students and educators, undergraduates, graduate students, local college and university faculty and our dedicated volunteer staff.

Now I just need to think of a name for the lab! I was thinking of the CincyMolES Lab (Cincinnati Museum Center Molecular Ecology and Systematics Laboratory). We could have a Star-nosed Mole as our mascot maybe? OK, I don't study mammals but it's a neat critter and I thought the name was catchy! I'm happy to field other suggestions from my readers.


AOU/COS/SCO 2008 Meeting in Portland: Part II

Last week was the joint conference of the American Ornithologist's Union, the Cooper Ornithological Society and the Society of Canadian Ornithologists in Portland, Oregon. There were many excellent presentations on a variety of topics in ornithology. Below are, in my opinion, some of the highlights from the conference representing the cutting edge of avian research in North America.

- Rosemary Grant of Princeton University presented a plenary lecture summarizing her collaborative work with her husband, Peter Grant, and numerous students and post-docs on the evolutionary biology and ecology of Darwin's Finches in the Galapagos Islands. The Grants' work on selection on bill size in Darwin's Finches is a classic work, arguably the most famous and well supported examples of Darwinian natural selection in the wild. Now the Grants are tackling speciation and presenting their ideas on how Darwin's Finch species arise over time. Whether or not many currently recognized species of Darwin's Finch are indeed true evolutionary species or complex, polymorphic populations was a hot topic of debate behind the scenes in the lobbies of the Hilton and the bars and restaurants on the streets of Portland. It remains to be seen how the Grants' ideas on speciation will stand up to the scrutiny of their ornithological peers.

- Terry Chesser of the National Museum of Natural History along with co-authors from museums around the country such as the University of Kansas and Louisiana State University presented new data on the relationships of one of the largest and most problematic groups of passerine birds, the Neotropical ovenbirds of the family Furnariidae. The woodcreepers were found to be monophyletic (meaning all the birds currently assigned to the woodcreeper group were found to share a single common ancestor). Two main groups were distinguished within the Furnariidae the woodcreepers and the "true" furnariids, or simply the rest of the furnariids.

- Townsend Peterson of the University of Kansas discussed the power of museums in understanding the spread of animal-borne diseases (aka zoonotic diseases). The "bird-flu" or H5N1 virus has the potential for a global pandemic and since 2003 has persisted as a lingering threat to human health, especially in south and south-east Asia. Peterson's group found in surveys of birds collected from south China that H5N1 is not exclusively a disease found in galliform birds (chickens, etc.) and waterfowl but is also found among passerines (i.e. songbirds) and other wild landbirds. Peterson also used bird banding databases to model the potential outbreak of zoonotic, bird-borne diseases, like H5N1, in North America and found that where the outbreak starts can have dramatics effects on the spread and geography of the subsequent spread. All of these findings can only be possible with large museum-led databases of both specimens and large scale sighting and banding records.

- John Wieczorek of the University of California at Berkeley presented an update on the ORNIS database. ORNIS is a distributed database that links together avian data from dozens of museum collections. Today the ORNIS database allows one not only to access holdings on avian specimens but also millions of sighting and banding records, digital photos and sound recordings. Wieczorek also discussed a new online tool, BioGeomancer, to add georeferencing data to existing specimen, photo, recording and sighting records. The power of these online, distributed databases and the georeferencing tools that accompany them was seen in numerous talks during this meeting. With adoption of it's new KE EMu database Cincinnati Museum Center is poised to join these other institutions in making it's collection more accessible and usable by researchers in novel and powerful ways.

- An entire session was devoted to the hot topic of subspecies in ornithology. The traditional way in which scientists name species is the binomial, the familiar genus and species names given to every organism. However, there is variation within species and to incorporate this variation into taxonomy many have adopted a trinomial system of nomenclature consisting of three names for each species, genus, species and subspecies. Kevin Winker of the University of Alaska at Fairbanks gave a good history of the use of trinomial nomclature in ornithology and discussed why divergence in phenotpyes (those characteristics of an organisms most often accessible to direct observation such as size, color, etc.) is not also equal to genetic divergence. This means that often the readily observable, physical traits used to distinguish between different subspecies of birds may not correspond to much genetic variation and thus may be of little evolutionary significance when it comes to distinguishing independent genetic lineages. Susan Haig of the USGS Forest and Rangeland Ecosystem Science Center discussed the problems that differing species concepts and subspecies designations pose for conservation efforts. Haig believes that subspecies designations are critical for conservation and law enforcement purposes even if their biological footing is less than solid. These points were hotly debated in the session and in discussions outside the talks.

- Perhaps my favorite talk of the entire conference was by Matt Carling and Rob Brumfield of the Louisiana State University Museum of Natural History. An idea in evolutionary biology known as Haldane's Rule says that in hybrids the sex that contains two different sex chromosomes (the heterogametic sex) should be less fit than the sex that contains two of the same sex chromosomes (the homogametic sex). A bad version of a gene can be overruled by the action of a good version of the same gene on another chromosome. Therefore heterogametic hybrids will be affected by all deleterious alleles on a sex chromosome. Haldane's Rule has been shown to predict the weaker sex in hybrids in everything from insects to mammals. In humans, and most other mammals, males are the heterogametic sex by virtue of having X and Y sex chromosomes while females are the homogametic sex having two X chromosomes. However, in birds females are the heterogametic sex with W and Z chromosomes and males with two Z chromosomes. Lazuli and Indigo Buntings hybridize in the central US. Carling and Brumfield measured the change in gene frequency across a hybrid zone between Lazuli and Indigo Buntings for both nuclear genes and genes linked to the sex chromosomes. They found much smaller genetic clines for sex-linked loci than for autosomal loci (those loci on chromosomes other than sex chromosomes). This is consistent with sex linked genetic incompatibilities in the hybrids. They also identified one locus in particular that contributed very heavily to this narrow genetic cline in Lazuli and Indigo Buntings. This loci was matched to a similar sequence in the chicken genome which, in chickens, contributes to the failure to lay eggs. Essentially Carling and Brumfield have identified an important gene which contributes to the maintenance of Lazuli and Indigo Buntings as discrete species. An amazing study which I hope to hear more about in the future.

- A fantastic symposium was presented on the last day of the conference in which some of the top curators and collections managers in ornithology presented techniques on preparing and managing material in avian collections. University of Kansas curator Mark Robbins and University of Washington Professor Emeritus Sievert Rohwer presented a live demonstration of their study skin preparation techniques. With some relatively minor differences our volunteers in the ornithology collection at Cincinnati Museum Center are preparing specimens like the pros do it, however, I did pick up some useful tips that will improve our specimens. Kimberly Bostwick of the Cornell University Museum of Vertebrates demonstrated her techniques for preparing skeletal material from bird specimens, again as a live demonstration. This was also very useful as here at Cincinnati Museum Center we plan on a major push towards increasing the collection's avian skeletal holdings. Also, Kevin Winker of the University of Alaska at Fairbanks presented a general overview of the tools of the trade for avian collecting from the intricacies of the permitting process to auxillary barrels for a shotgun! All of the talks in this session provided useful tips for the growing bird collection at Cincinnati Museum Center but they also reaffirmed that the changes implemented in our protocols have put us on the right track towards having a world class ornithology collection.

-Finally Irby Lovette of Cornell University presented some interesting, if not troubling, results on measuring genetic diversity using molecular genetic markers. Researchers for various reasons often want to know the genetic diversity of an individual organism. Genetic diversity in an individual is typically measured in terms of heterozygosity. At any particular location in an individual's genome (at least for sexually reproducing organisms) there will be two copies of a particular gene. If those two copies are the same the individual is homozygous at that locus if they differ then the individual is heterozygous a that locus. Researchers use different types of genetic markers to determine the degree to which an individual is heterozygous across it's entire genome. However, Lovette demonstrated that different markers do not agree with one another on genome-wide heterozygosity. A level of heterozygosity determined using one type of marker may not correspond to the same level determined by another marker. Even multiple loci of the same types of markers often do not agree. This work is consistent with previous findings showing that levels of relatedness and inbreeding were only evident using very large numbers of genetic loci and that molecular genetic markers were inferior to good pedigree data in determining genetic diversity. However, there are many correlations in birds between molecular genetic based genetic diversity and various fitness measures, such as hatching success or growth or behavioral measures. The question then is what do these correlations mean? This will be a fertile field for future research for sure!


AOU/COS/SCO 2008 Meeting in Portland: Part I

This week was the joint conference of the American Ornithologist's Union, the Cooper Ornithological Society and the Society of Canadian Ornithologists in Portland, Oregon. This meeting celebrated the 125th anniversary of the American Ornithologist's Union(AOU) and ushered in a new president for the AOU, Dr. Edward "Jed" Burt who is a faculty just down the road from Cincinnati in Delaware, OH at Ohio Wesleyan University. It was a great meeting and many important ties were forged between Cincinnati Museum Center and researchers and natural history museums around North America and the world. I meet with friends and colleagues from the University of Windsor, University of Alaska at Fairbanks, the Taiwan Endemic Species Research Institute, University of Cincinnati, Auburn University, the Delaware Museum of Natural History, the Cleveland Museum of Natural History, and many other colleges, universities and museums and promoted greater use of the collection and plotted out new collaborations and research projects.

There were many excellent talks on the latest findings in ornithology and my next blog will provide a survey of some of the highlights, but, perhaps most useful was a nearly day long symposium on avian museum collections that included live demonstrations of the latest preparatory methods from some of the top curators and collections managers in the country. This symposium in particular proved to be invaluable and provided me with a wealth of information from preparation to permits that will greatly improve the collection at Cincinnati Museum Center. Also, meeting with colleagues and forging new ties resulted in several new projects. The plan is have in house research at Cincinnati Museum Center result in at least 10 new publications over the next year. A bold goal but one that can be achieved through the numerous collaborative efforts between Cincinnati Museum Center Zoology Department and top researchers in avian biology from around the globe.

Of course I take every opportunity to increase the collection at Cincinnati Museum Center and collected many digital photos to go into a growing georeferenced digital resources database for birds. The meeting reinfornced the utility of this growing type of natural history collection in several talks regarding the ORNIS distributed database system. I gained new insight during this part of the meeting on how to manage these collection and provide proper georeferencing (location data critical to making a useful digital resources collection). Also I learned of new ways in which digital resources in ornithological collections are being used alongside both traditional material (skins, skeletons, spread wings, etc.) and frozen tissue collections. Shown in this blog entry are three new digital photos to be archived in a growing digital resources database for ornithology (Top, Northern Fulmar; middle, Barred Owl; bottom, Pacific-slope Flycatcher).


On the flip side...

Critics of evolution often point to a perceived lack of transitional forms in the fossil record as evidence that some forms of life don't share a common genetic heritage but rather arose independently. Creationists have been using this line of argument for over a hundred years. But, they do so in spite of the evidence. Intermediate forms are those organisms that have a mosaic of characteristics linking two seemingly unrelated groups or an organism that exhibits a character state in between those found in two or more other organisms. Creationists claim these forms are lacking in the fossil record. However, the transition between theropod dinosaurs and modern birds, the evolution of the mammalian ear bones from a reptilian jaw, the evolution of whales from terrestrial mammals and even the fossil record for our own species are all classic examples of evolutionary transitions complete with several intermediate forms.

Add to the growing list of evolutionary transitions another example from the fossil record. Vertebrate animals have a bilateral body plan, that is they exhibit a front and back and dividing the body down the middle results in two symmetrical sides. There are few exceptions to the symmetrical vertebrate body plan. One striking exception familiar to us all are the flatfishes (Order: Pleuronectiformes). This group includes fish found at your local market or seafood restaurant including sole and halibut. Adult flatfishes are asymmetrical. They start off life with the typical symmetrical body found in other fishes however as they grow their skull undergoes a radical developmental change with the eyes rotating to one side of their head. A flatfish on the sea bed is therefore a fish essentially lying on it's side with an asymmetrical head. Imagine lying on your left side with both your eyes on the right half of your face and you'll get the picture.

The question is how did this unusual body plan evolve? There are clear benefits to exploiting an open ecological niche and becoming specialized to be a bottom feeder but doing so can mean a radical change in an organism's body plan. The flatfish body plan clearly evolved from a typical symmetrical fish plan. Comparing the details of flatfish anatomy and their genes shows that they fit within the large radiation of bony fishes, nearly all of which have a symmetrical body plan. Also, the turbots (Psettodes sp.) are the living representatives of the earliest branch of the flatfish family tree and it, as expected if flatfish evolved from a symmetrical ancestor, they have one eye that doesn't quite make it all the way around the head during development. What's more, the adult asymmetrical flatfish plan develops from a symmetrical larval body plan. Together all these data indicate that the asymmetrical flatfish plan evolved from a symmetrical ancestral body plan. However, as creationists are fond to ask, where are the intermediates?

Along comes University of Chicago evolutionary biologist Matt Friedman. In the July 10th edition of the journal Nature Friedman provides evidence for the evolutionary transition between symmetrical bony fishes and the asymmetrical flatfishes. Friedman provides highly detailed descriptions of fossil fishes in the genus Amphistium and describes a new species, Heteronectes chaneti. These fossils were available to researchers before, however, Friedman applied computed tomography to the specimens to obtain detailed three-dimensional images of their anatomy. Computed tomography involves moving an x-ray source and detector around a specimen and digitally reconstructing a detailed three-dimensional image from the x-ray exposures. Previously it was difficult to tell an asymmetrical flatfish-style skull from a symmetrical skull crushed by the weight of sediment during fossilization. With the new imaging technology Freidman concluded that these fossil fish do indeed show different intermediate stages leading to the fully asymmetrical modern flatfish body plan. Specifically, the part of the skull containing the orbits, the neurocrania, rotates over evolutionary time. A close relative of the flatfishes, Trachinotus, shows the classic symmetrical condition with one eye on either side of the head. The fossil Amphistium and Heteronectes show an intermediate stage with one eye squarely on one side of the head and the other eye on the other side of the head but shifted up towards the top of the head. The earliest branch on the flatfish family tree, the turbots, one eye rests nearly on top of the head and in the rest of the flatfish the eye has migrated fully to the other side of the head.

New findings are popping up all the time from fields ranging from paleontology to developmental genetics that affirm the conclusion that life shares a common ancestry and that these unusual body plans, such as the asymmetrical head of a flatfish, have arisen through evolutionary processes.

Friedman, M. (2008). The evolutionary origin of flatfish asymmetry. Nature, 454(7201), 209-212. DOI: 10.1038/nature07108