Emma Goldberg Publishes Work on Species Extinctions in Evolution Journal
Emma Goldberg Publishes Work on Species Extinctions in Evolution Journal
Emma Goldberg, a Los Alamos National Laboratory and New Mexico Consortium scientist, has recently published her work “Heterogeneity in the rate of molecular sequence evolution substantially impacts the accuracy of detecting shifts in diversification rates” in the science journal Evolution.
Throughout the history of life, lineages have repeatedly split into new species, while others have gone extinct. These processes (speciation and extinction) shape the tree of life and help explain the extraordinary diversity of organisms found on Earth today. For many years, evolutionary biologists have sought to identify the factors that influence how quickly lineages diversify or disappear over time.
To study these patterns, researchers often use phylogenetic trees, which show relationships among species and their common ancestors. By analyzing these trees, scientists can look for shifts in diversification rates, or changes in how quickly new species form and existing species go extinct. They can then investigate whether those shifts are associated with particular traits, environments, or evolutionary events.
Theoretical biologists have long predicted that speciation and extinction rates vary across the tree of life. However, Goldberg and her colleagues show that detecting these shifts may be more complicated than previously understood. Their research demonstrates that differences in the rate of molecular sequence evolution can introduce systematic biases into inferred phylogenies. These biases can then lead researchers to incorrectly identify patterns of lineage diversification.
In particular, the study found that asymmetric rates of sequence evolution can make models with diversification rate shifts appear more likely, even when those shifts may not accurately reflect the underlying evolutionary history. As the asymmetry in molecular evolution increases, so does the tendency to select more complex models that include changes in diversification rates.
These findings have important implications for evolutionary biology. They suggest that conclusions from previous studies identifying shifts in diversification patterns should be interpreted carefully, especially if potential biases in molecular substitution rates have not been fully evaluated.
By highlighting a source of error in commonly used analytical approaches, this research provides an important caution for scientists studying macroevolutionary patterns. It also underscores the need for continued refinement of phylogenetic methods so researchers can more accurately understand how species diversity has evolved across the tree of life.
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