In what totally sounds like a mash-up of two of Jeff Goldblum’s best movies, The Fly and Jurassic Park, scientists at New York University and the University of Chicago have created mutant fruit flies carrying reconstructed genes from 140 million years ago. The goal? To shed some light on the process of evolution and how it has changed the development of fruit flies over millions of years.
The work, described in the journal eLife, was achieved using cutting-edge gene insertion techniques to replace a particular modern day protein with ancestral proteins in a living fly. The purpose was to test whether it could create functions which had long since been absent. The scientists discovered that two mutations millions of years ago altered the function of a developmental gene, which regulates development of the fruit fly’s head. This chance mutation has since become an indispensable aspect of modern fruit flies. Fly embryos without the modern day Bicoid protein die very early since they form tail structures at both ends of their body, rather than forming a head.
“Ancestral changes in protein sequences are thought to be responsible for the evolution of diverse animal forms, but finding which historical changes were most critical has eluded scientists until very recently,” Stephen Small, an NYU biologist, told Digital Trends. “The ancestral protein’s function was to bind to a specific set of DNA sequences, and turn on a set of target genes based on that sequence. By comparing the ancestral protein sequence with its modern day descendants, the research team identified two specific amino acid changes that allowed the modern day protein to bind to a completely different set of DNA sequences, compared to the ancestral protein. [The work] further showed that these changes allowed the [modern] protein to activate a novel set of target genes in the developing embryo and acquire a central role in the embryogenesis of a subset of insect species.”
The two amino acid changes identified by the researchers endow the ancestral protein with some of Bicoid’s modern day activities. However, there are still questions to be answered. Specifically, the researchers want to know which changes occurred to evolve a fully functional Bicoid protein. “We are currently extending our studies to identify all the sequences changes that led to the evolution of the modern day protein,” Small said.
No, we’re not going to see 140-million-year-old flies buzzing around any time soon. But between this work and Harvard University’s work to bring back the woolly mammoth through cloning, this is sure an exciting time in our history. Better yet, make that pre-history!
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