This week, new parents Catherine and Richard were shocked to
find their baby boy has totally Caucasian skin, and not a darker tone as
expected. It was a one in a million chance - but here's how it happens.
Catherine and Richard Howarth were convinced they'd been
given the wrong child by mistake - their newborn baby boy was white and not
dark-skinned as they'd expected. It's an unusual story - but it's not the first
time that it's happened. How does this sort of thing occur and why?
His mother probably had
a white ancestor
The baby's father Richard is white, but mum Catherine has
dark skin from her Nigerian heritage. Genes from one of her ancestors may have
lain dormant for generations - until randomly thrown together in the new baby,
they brought out traits that had been latent for so long. This is what's known
as a genetic/evolutionary throwback, or atavism.
A one in a million
chance
Melanin is the pigmentation in skin that determines a
person's skin colour. Groups of people whose ancestors lived closer to the
equator - where there's more UV radiation - tend to have darker skin.
But the combinations of genes thrown up everytime a baby is
born means that mixed-race child can be anywhere on a spectrum between its two
parents.
The genes that control the amount of melanin in someone's
skin operate under "incomplete dominance" which means no specific
trait over-rules the others. All of the variant gene traits are completely
expressed, and visually this will mean a mixed-race child's skintone will be a
visual mix of its parents.
The chances, however, of Catherin and Richard’s child to be
white would be far, as the recessive gene could be just one in 20 alleles - in
fact, the chances of this happening were calculated at roughly one in a
million! WOW! Yet it happened!
The story of a baby coming out a surprising colour isn't the
first of its kind - there have been many examples of children being born a
different colour to their parents.
One of the saddest - and most famous - stories is that of
Sandra Laing. Sandra is a black-skinned woman who was born to white parents in
apartheid South Africa and forced to leave home at the age of ten.
People have also had children who have differently-coloured
skin to their siblings. In 2005, Kylee Hodgson and Remi Horder had twin girls -
one black and one white.
culled from mirror.co.uk
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