We always seem to want what we can’t have and when it comes curly hair, some of us spend a lot of time trying to make it straight.
And despite years of research, it hasn’t been known until now why hair curls naturally – until now.
“We didn’t have the science to prove it one way or the other,” says AgResearch senior scientist Dr Duane Harland.
Sheep waiting for sale Photo: RNZ/Susan Murray
Harland says sheep have provided the key.
Wool or hair found at the bottom of any animal’s coat is made up of finer fibres than the rest.
“People observed that wool has curvature and different cells inside it and that those cells are arranged on one side of the fibre or the other,” Harland says.
When Harland started out in wool research, data was collected from testing different bits of wool under the microscope. Narrowing that down to wool from the underside of the sheep provided him with the missing link.
Harland says every curl is unique and produces curvature in a slightly different way. Discovering this required looking at the same piece of wool at least 500 times using confocal microscopy.
“We use fluorescent dyes to stain the different kinds of cells, so we’ve got bright green and bright red and we’re looking at it in three dimensions.”
The process involves taking slices all the way through the cell, at which point the bright glowing fibres no longer look like wool.
“Hair curls because [there are] different kinds of cells on either side,” he says.
“As the hair grows inside the skin - either in the scalp or in the sheep’s skin - some of those cells elongate.”
Harland says hair is built up like a column of blocks and continues to be pushed up until it becomes a tube. At some point, one side gets longer, while the other side stays the same. This causes the whole thing to tip over, turning into an arch.
Photo: Supplied / AgResearch
“That difference of length between the ones on the outside and ones on the inside determine how much it curls,” Harland says.
And the reason curly hair becomes frizzy in humid conditions is no different for a sheep.
“The different cells react to water [and] lengthen and shorten depending on humidity.”
Discovering the secret to curly hair has been a hot topic of intrigue - Harland’s research has been featured in the New York Times and on the ABC. The research has also been published and the data has been published in the Journal of Experimental Biology
At this stage, the research isn’t going to be used for any particular product development, but will provide a useful insight for future work.
