Scientists have been studying evolution for centuries, but new research is challenging some established beliefs. A recent study on beetleweed (Galax urceolata) in the Appalachian Mountains reveals surprising details about how different versions of a species can coexist.
The study, led by Shelly Gaynor at the University of Florida, examines how organisms with multiple genome copies (autopolyploids) interact with their original diploid versions. Autopolyploidy is when an organism duplicates its chromosomes, creating instant genetic diversity.
Previously, scientists believed autopolyploids were rare and couldn't coexist with their diploid relatives due to competition. Gaynor's study suggests this might be wrong. "Through my fieldwork, I discovered that a single population could have a mishmash of cytotypes, which fascinated me," said Gaynor.
Researchers built a mathematical model that includes demographic and environmental randomness to understand how different chromosome types interact. The model tracks the formation, establishment, and persistence of diploids, triploids, and autotetraploids, even with gene flow.
The results show that high self-fertilization rates and strong reproductive barriers help multiple cytotypes coexist. Autotetraploids appear to have an advantage over diploids in stressful environments or intense competition.
This challenges the idea that autopolyploids must live separately from their original species. The study suggests genetic and ecological factors allow them to thrive together. This work adds to growing evidence that evolution doesn't always follow a straightforward path.