Evolving New Skeletal Traits by cis-Regulatory Changes in Bone Morphogenetic Proteins.

Area of Science:

• Evolutionary biology
• Genetics
• Developmental biology

Background:

• Skeletal evolution involves changes in bone size and shape across vertebrate species.
• Regulatory DNA alterations are crucial drivers of evolutionary modifications in skeletal structures.

Purpose of the Study:

• To identify specific regulatory DNA alterations controlling skeletal evolution.
• To investigate the role of BMP family member GDF6 in skeletal size and shape changes.

Main Methods:

• Genetic crosses and comparative genomics in sticklebacks.
• Transgenic overexpression of GDF6 in fish.
• Functional analysis of regulatory elements in the human GDF6 locus.

Main Results:

• Armor bone-size differences in sticklebacks are linked to the GDF6 locus.
• A transposon insertion increases GDF6 expression in freshwater fish, mimicking evolutionary changes.
• Loss of a conserved enhancer in humans affects GDF6 expression in limbs, correlating with bipedalism adaptations.

Conclusions:

• Both gain and loss of regulatory elements can direct BMP changes to specific anatomical sites.
• Regulatory evolution provides a flexible mechanism for species-specific skeletal form development.