Many people wish at one time or another that they had curly hair. Most people know that it’s genetic, so the know the why, but they don’t know the how. So what is it that makes hair curly?
The genes that cause curly hair are passed from parent to child, but that doesn’t mean the parent’s hair and the child’s hair will match. There are plenty of factors that can affect how a gene (or genes) is expressed. In the case of curly hair, a 2009 study found that the amount of curl in a parent’s hair had between 85 and 95 percent of a chance of being expressed directly in the child. So if you have tight curls, there is a very good chance that your child will also have tight curls.
Quantifying Curly Hair
Curls tend to be categorized by both the tightness of the curl and the texture of your hair. Both factors influence how your curls will express themselves.
Everyone has hair texture. Some people have baby fine hair that is difficult to style. Some people have thick hair that comes with its own set of complications but can hold a style much better. Most styles of curly hair involve thicker hair, which leads to more volume and is one of the things that makes curly hair more difficult to manage. Thick hair, like curly hair, is significantly an issue of genetics. Even with people with straight hair, some genetic backgrounds are more likely to have thick, coarse hair than others. Europeans and others from that region are more likely to have fine hair than say, people from the Mediterranean.
What Causes the Curl?
If you imagine what a strand of hair looks like either in person or in a diagram, that strand is usually round. That’s because the follicle is round. Round hairs are straight hairs. They come out of the follicle straight outwards and continue to grow straight down the strand.
In the case of curly hair, the follicle is of a different shape. While most often this is genetic, there can be other rare causes of hair turning curly, such as damage to follicles.
In cases of wavy or curly hair, the follicle becomes oblong instead of round, which creates a strand of hair that grows out looking compressed. The more oval or even flat the follicle is, the more oval or flat the hair it grows will be, and the more curl that strand will have.
There are other factors that can influence how curly your hair is. Weather and humidity, shampoo and styling products, how long your hair is and how it is cut all play their part in how your hair will look, but those causes are after the fact. It is the shape of your follicles that determine how curly your hair is supposed to be. The rest of the factors just work with or against your natural curl.
If you have curly hair, the general consensus is that you should count yourself lucky, no matter how unruly your curls may be. There are plenty of products on the market available to help keep your curly hair shiny and manageable. Curly hair doesn’t have to be a chore, but any amount of making it easier to deal with is going to have to come in after it leaves the follicle in all its curly glory.