I give, a king, to me, she does, alone, up there, yes see, I double give
When it comes to genes, evolutionary biologists have traditionally favored seniority. Genes thought to be most essential to life must be ancient and conserved, the assumption goes, handed down from species to species as the basic instructions of life. That sharing is evident in early developmental stages, which 19th-century biologist Ernst Haeckel observed to be very similar between different organisms in his famed recapitulation theory. The genes that drive those early stages of development are also shared by creatures as different as flies, mice, and humans, lending support to the idea that the most important genes for life go a long way back on the evolutionary tree.
By comparison, new genes haven’t gotten nearly as much credit. Arising more recently in evolution’s history, rookies that only count their age in tens of millions of years were thought to be less important - providing new functions and features that were nice, but not essential. If old genes were the bread and butter of life…
“Maybe the new genes serve a function like vinegar or soy sauce,” said Manyuan Long, professor of ecology & evolution at the University of Chicago. “They make your life better, change behavior, help a male find females more efficiently, but that’s all.”
But that ageist perspective is shaken in this week’s Science, courtesy of an exciting new study from Long’s laboratory. Using the fly species Drosophila melanogaster, Long, graduate student Sidi Chen, and postdoctoral researcher Yong Zhang tested whether silencing a new gene would be as fatal as silencing an old one. (…)
Another surprise implication of the data is the speed with which new genes can become an indispensable part of a species’ genome. When a new gene appears in a species due to evolution, one would not expect it to be immediately crucial - otherwise, how did the species survive before its arrival? But like a new employee in an office, a new gene can make itself essential by forming relationships with older, essential genes through what are called gene-gene interactions. Before long, the new gene has become a key part of the species’ survival…and there’s no turning back.
photo { Jeremy Liebman }
