In the awesome YouTube video below by Veritasium, Derek Muller explains why women are stripy.

I won’t give too much away, but I’ll briefly introduce the topic of epigenetics for those who don’t know much about it. Epigenetics refers to changes gene activity that occurs without alterations to the DNA sequence itself. Epigenetic modifications can switch genes on or off and determine which particular proteins are produced in different cells of the body.

Epigenetics is essential since all of the cells in your body possess the same DNA sequence, but different types of cell require different proteins to be produced. It is these changes in gene expression that are therefore responsible for the different types of cell found in the body, or cell specialization. Gene silencing (switching off genes) is also important in the inactivation of the second X chromosome found in female mammals so that females don’t produce twice as many X-chromosome gene products as males.

There are a few different ways to silence genes, for example DNA methylation. This process involves the addition of a methyl group to a specific region of DNA, altering its structure and consequently changing the way that a particular gene interacts with the machinery needed to produce RNA, a pre-requisite for protein production.

Check out this video to find out more: