THAT’S THE WHY
Freckles – they are an immediately recognisable “Irish” trait, up there with blue eyes and red hair. And they have been around for a long time: fossils found recently in China show that even some dinosaurs had freckled colouring.
But what are they? And why do some people have a light dusting, if any, while others are covered from ear to ear?
Freckles are caused by an uneven distribution of the tanning pigment melanin, which is produced by specialised cells in the skin after exposure to sunlight or artificial UV light.
A freckle turns up in patches where there is a higher level of melanin than the surrounding skin, and the small, flat tanned area is particularly noticeable on a fair complexion.
The number of freckles you have is down to a combination of genes and environment.
Research shows that identical twins have similar numbers of freckles more frequently than non-identical twins, but the genetic background to freckles is complex.
Variations in the MC1R (melanocortin 1 receptor) gene involved in melanin production have been linked to freckles in people of European descent, while a 2004 study of Chinese subjects mapped another freckle gene to chromosome 4q32-q34.
But even if you have freckly genes from birth you are not born with freckles – they arise during childhood and tend to crop up on sun-exposed regions of the body. They are more pronounced in summer, generally stop spreading around adolescence and may not be as noticeable with age.
Freckles are harmless, but the fair skin they tend to be linked with can sunburn easily, and anyone who notices a change in any area of pigmented skin should get it checkedout.
– CLAIRE O’CONNELL
