Do you have your mum’s button nose? Did your dad pass on the curse of sneezing in bright sunlight? And where did your baby’s red, curly hair come from when there hasn’t been a redhead in your family for generations? These questions may sound simple but the answers get complicated fast. Why? Because the science of genetic inheritance is complicated, says genetic counsellor, Dawn Allain. “It’s nearly impossible to tease out exactly where each of your traits came from,” she explains. “Most traits are influenced by many different genes and you inherit some from each parent.” Plus, there’s the influence your environment plays; just because you have a gene for a certain trait doesn’t always mean you’ll end up with it, she adds.
How you inherit traits
Still, it’s fun to ask those questions and while there aren’t many detailed answers, there are a few basic things genetics can tell you about traits you inherit from your mum and those you got from our dad, Allain says. But first, you need to know how inheritance works.
“There are three main ways you can inherit traits from your parents,” she explains. First is through a dominant gene – if you inherit a dominant gene you will develop that trait. Take eye colour, for example. If either of your parents have brown eyes, you likely will have brown eyes as this is a dominant trait. Second is through a recessive gene – both parents have to have the recessive gene for you to have that trait. For instance, if you have blue eyes then both of your parents must carry a gene for blue eyes, even if their eye colour isn’t blue. Lastly, there are X-linked traits which are found only on the X chromosome and are passed on through the mother.
Your ability to lose weight
There are two types of fat in your body: ‘good’ brown fat, which increases your metabolism and helps you maintain a healthy weight, and ‘bad’ white fat, which can cause obesity and disease if you have too much of it. Everyone has some of each type but how much brown fat you have – and therefore how high your metabolism is – may be inherited from your mum, according to a study published in Nature Communications. Another trait you get from your mum is your intelligence.