Charles Darwin had first eluded to the Galapagos finches in the second edition of the Journal of Researches, published in 1845, more than 20 years before the publication of The Origin of Species: “Seeing this gradation and diversity in one small, intimately related group of birds [finches], one might really fancy that from an original paucity of birds in this archipelago, one species had been taken and modified for different ends [different species].”
Last week, the Center for Biomolecular Science & Engineering at the University of California in Santa Cruz (UCSC), California, announced last week that “scientists have sequenced the genome of one of the iconic Galapagos finches first described by Charles Darwin.”
The genome of the medium ground finch (Geospiza fortis) is among the first of a planned 100 genomes of vertebrate species to be sequenced by an international collaboration between the Genome 10K Project directed by David Haussler of the Howard Hughes Medical Institute, University of California, Santa Cruz and Beijing Genomics Institute (BGI) directed by Jian Wang headquartered in China.
This finch genome, the first of the Genome 10K-BGI collaboration, will be available through the UCSC Genome Browser when complete. The sequencing of the finch genome is touted as both a scientific and a symbolic advancement, according to Duke University associate professor Erich Jarvis, who studies the neurobiology of vocal learning in songbirds.
“The scientific advancement,” Jarvis said, “is that it will allow us to investigate the genomes of a group of closely related species with a significant amount of diversity on an island population, allowing us to potentially better understand the genetics of trait evolution.”
The ultimate purpose of the collaborative project is to discover the “slight, successive” evolutionary changes proposed by Darwin. At the time of the publication of The Origin of Species in 1859, by today’s standards, nothing was known about modern Mendelian genetics.
Technological advances in identifying the genomic sequences of a species now provides the tools to compare the genomic sequences of related species to study the genetic mutations that gave rise speciation (new species).
The BGI’s associate director of research, Goujie Zhang, said, “These finches are of great historical significance, but when Darwin first studied these birds, he was unlikely to have envisioned how this species would become a perfect model to study evolution in action.”
Zhang said, “Having the reference genome of this species has opened the door for carrying out studies that can look at real-time evolutionary changes on a genomic level of all of these enigmatic species.”
According to Genome 10K co-founder Stephen O’Brien, “The genome sequence empowerment of Darwin’s finches will initiate the solving of evolutionary riddles that have puzzled biologists for a century.” O’Brien is now chief scientific officer and director of the Dobzhansky Center for Genome Bioinformatics at St. Petersburg State University, Russia.
The cooperative efforts between the US, China, and Russia resolution to resolve the “evolutionary riddles” is an extremely high bar. Previous attempts to retrace the evolutionary genetic mutations responsible for differentiating species have not been successful.
The Genome 10K-BGI collaboration is not the first to examine the molecular evidence for evolution between the different finches, including DNA.
Akie Sato of the Max-Planck-Institut für Biologie in Germany lead a research team to study mtDNA, cytochrome C, and the control region of the Galápagos finches published their findings in the Proceedings of the National Academy of Science in 1999. The paper entitled “Phylogeny of Darwin’s finches as revealed by mtDNA sequences” concluded:
The traditional classification of ground finches into six species and tree finches into five species is not reflected in the molecular data.
In reexamining the evidence, Sato headed another research team to study the same molecular markers in a finches closely related to Darwin’s finches, the Tiaris olivaceu species. In the article entitled “On the Origin of Darwin’s Finches,” published in the journal Molecular Biology and Evolution in 2001, Sato concluded –
The absence of a detailed and statistically well supported phylogeny of the genus Tiaris, we are currently unable to reconstruct their morphological evolution and distinguish between these possibilities.
The results from the two studies point to the same conclusion—the molecular evidence from the finches cannot be arranged into an evolutionary Tree of Life scheme. This means that there was no evidence that Darwin’s finches evolved from one species into a number of species.
Peter and Rosemary Grant, a husband and wife team from the University of Cincinnati, who had dedicated their careers to the study of Darwin’s finches in an article entitled “Comparative landscape genetics and the adaptive radiation of Darwin’s finches: the role of peripheral isolation” in the September 2005 issue of the Molecular Ecology journal observed a “decoupling of morphological and molecular evolution”. In other words, the physical nature of the finches cannot be defined by any evolutionary molecular composition changes in the finches.
The growing disappointment in the concept that evolution is the result of molecular changes through genetic mutation has reached the proverbial tipping point.
“One spur to research on mutations was the hope that an accumulation of these might lead to a new species. But”, according to Italian geneticist Giuseppe Sermonti, “this never happened”. For these reasons, large segment of the evolution industry abandoned neo-Darwinism, otherwise known as the Modern Synthesis theory.
The evidence from the Genome 10K-BGI genomic sequencing of Darwin’s finch collaboration is more likely to point a “decoupling of morphological and molecular evolution” rather than a coupling of evolution through “slight, successive” genetic mutations as anticipated by Darwin’s theory of evolution “by means of natural selection”.
Evolution was once a theory in crisis, now evolution is in crisis without a theory.