Differences between ultrastructure and protein composition in straight hair fibres

Area of Science:

• Mammalian hair biology
• Proteomics
• Structural biology

Background:

• Mammalian hair traits like curvature are complex, poorly understood emergent properties.
• Hair structure influences coat function, such as thermo-insulation.

Purpose of the Study:

• Compare hair curvature, ultrastructure, microstructure, protein composition, and felting properties.
• Investigate straight-wool mutants (felting lustre-mutant sheep) against wild-type relatives and English Leicester sheep.

Main Methods:

• Comparative analysis of hair morphology and proteomics.
• Examination of cuticle, cortical protein layout, and ultrastructure.
• Assessment of felting properties.

Main Results:

• Lustre mutant fibers share basic building blocks but differ in internal patterning (orthocortex/paracortex arrangement).
• Mutant fibers show reduced high glycine-tyrosine proteins and altered KAP8/KAP16 protein expression.
• Internal patterning variations correlate with hair curvature and potentially felting properties.

Conclusions:

• Multiple internal patterning strategies can produce hair curvature.
• Variations in fiber patterning affect mechanical phenotype.
• Felting lustre mutant sheep are valuable for studying mammalian fiber development.