Evolutionary Biologist Craig Albertson Identifies Non-genetic Source of Species Variability

An unspoken frustration for evolutionary biologists over the past 100 years, says Craig Albertson at the University of Massachusetts Amherst, is that genetics can only account for a small percentage of variation in the physical traits of organisms. Now he reports experimental results on how another factor, a “bizarre behavior” that is part of early cichlid fish larvae’s developmental environment, influences later variation in their craniofacial bones.

Albertson has studied African cichlid fish for 20 years as a model system for exploring how biodiversity originates and is maintained, with a focus on genetic contributions to species differences. In a new series of experiments with former Ph.D. student Yinan Hu, now a postdoctoral fellow at Boston College, they examined a “vigorous gaping” behavior in larval fish that starts immediately after the cartilaginous lower jaw forms and before bone deposition begins. Results appear in the current early online issue of Proceedings of the Royal Society B.

As Albertson explains, “We predicted that the baby fish are exercising their jaw muscles, which should impose forces on the bones they attach to, forces that might stimulate bone formation.” Albertson and Hu observed that gaping frequency, which could reach as high as 200 per minute, varied by species “in a way that foreshadows differences in bone deposition around processes critical for the action of jaw opening.”

Read more in the Royal Society Publishing article

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