Unicorn genome sequenced
Researchers release a draft genome of the famous horned equine, cause stir in evolutionary and philosophical circles.
1 April 2013
A high-quality draft of the unicorn genome is released by the Equid Sequencing Consortium in today’s issue of Philosophical Transactions in Genomic Sciences . Researchers have previously deciphered the genome of the domestic horse  and reported partial sequencing data from Przewalski’s horse and the tibetan wild ass [3,4]. The unicorn, however, is the first horned equine to be sequenced. Scientists hope that the new data will explain origins of the horn and help identify key genes that drive horn development.
A whale in the equine tree
Dr. Elizabeth Siva and her group EMBL-EBI focused on phylogenetic analysis of the data. “Our calculations suggests that the unicorn diverged from a common ancestor with other modern members of the Equidae family, such as zebra and horse, around 14 million years ago.” It’s around this time, she said, that entire chromosomal fragments, most closely related to known narwhal, entered the unicorn lineage. The origin of the unicorn’s horn has long been a topic of debate in the unicorn field, with many considering it to be yet another striking example of convergent evolution. “What this looks like, though,” says Siva “is a genuine instance of intercrossing between a terrestrial and marine mammal.” Although she expects continued skepticism from members of the convergence camp, she’s confident that further analysis will only strengthen initial conclusions.
Professor Matthew Hofer, who has led the unicorn sequencing project since 2011, says the work represents a major technological milestone. His group at UCSC faced numerous challenges not presented by more widely recognized species, whose genomes they have deciphered in the past. “We struggled for months to develop adequate protocols for sample collection and DNA extraction. We just didn’t encounter these sorts of problems with species for which existence has been firmly established.”
Scientists also expect their finding will contribute to long-standing philosophical debates. A colleague for Professor Hofer’s in the Department of Philosophy, Scott Trimpton, says the work supports a theory according to which nonexistent things are still real . But, she cautions, further scholarly thought must be devoted to the matter. This is not the first time research into horse genetics has transcended academic disciplines. Previously, German researchers studied coat-color genetics of pre-domestic horses to show that paleolithic cave paintings were more literal representations of contemporary animals than previously thought .
- Deal, N.S., Catabia, D., Hofer, M., and Siva, E. (2013) The Sequence of the Unicorn Genome. Philosophical Transactions in Genome Sciences, 17(8), 156-68.
- Wade, C. M., Giulotto, E., Sigurdsson, S., et al. (2009). Genome sequence, comparative analysis, and population genetics of the domestic horse. Science, 326(5954), 865–867.
- Luo, Y., Chen, Y., Liu, F., et al. (2011). Mitochondrial genome sequence of the Tibetan wild ass (Equus kiang). Mitochondrial DNA, 22, 6–8.
- Goto, H., Ryder, O. A., Fisher, A. R., Schultz, B., Kosakovsky Pond, S. L., Nekrutenko, A., & Makova, K. D. (2011). A massively parallel sequencing approach uncovers ancient origins and high genetic variability of endangered Przewalski’s horses. Genome biology and evolution, 3, 1096–1106.
- Russell, B. (1905) On Denoting. Mind.
- Pruvost, M., Bellone, R., Benecke, N., et al. (2011). Genotypes of predomestic horses match phenotypes painted in Paleolithic works of cave art. Proceedings of the National Academy of Sciences of the United States of America, 108(46), 18626–18630.