• Question: How come I look more like my cousin than my mum and dad?

    Asked by purplewolf9 to Andrew, Emma, Marianne on 14 Jun 2010 in Categories: .
    • Photo: Andrew Maynard

      Andrew Maynard answered on 14 Jun 2010:

      Hi purplewolf,

      You and your cousins have obviously got some genes from your grandparents dominating your looks. But I’ll stop there before my co-scientists start making fun of my lack of knowledge on genetics and inheritance!

    • Photo: Marianne Baker

      Marianne Baker answered on 14 Jun 2010:

      Ah purplewolf9, I’m starting to enjoy your questions!

      So, for this it might be good to make a tree on a piece of paper. I’m going to assume that your cousin’s dad (your uncle) is your dad’s brother for this.

      First you want to think about your grandparents.
      They had one of your parents and one of your cousin’s parents; so your dad and uncle both have genes that have come from your grandmother and grandfather.

      Then, your uncles and your dad married unrelated women and had their kids, who will have some genes passed down from your grandparents. So, you have genes in common with your cousin.

      In your dad’s case it may be that the genes contributing to appearance are less ‘strong’ than the equivalent genes that you and your cousin have; so while you may not look that much like your dad or your uncle (I’m not mentioning your mum or aunt here as they come from ‘outside’ this tree), it’s perfectly normal that you look similar to your cousin!

      Again, it helps to draw that on some paper – I did 😛

    • Photo: anon

      anon answered on 14 Jun 2010:

      There’s lot of different reasons why that might be. it could be as simple as because your mum and dad are old and your cousin’s young. When your mum and dad were young did they look more like you?

      Additionally you share genes with your cousin (that he/she got from your grandma/grandpa) though you’re correct in assuming that you should share more genes with your parents. You don’t inherit exactly the same genes as your mum or your dad and you may even have some genes that they don’t have. Some genes are better at getting inherited than others. This is part of the process that lets us adapt to the environment and means that the population survives over time.

      This is a field of biology that keeps getting more and more complex. Turns out it’s not just the genes that are important but the way they are put together and the scaffold that supports them.

      The key message is that variation is a good thing and important for our survival. I just hope that you’re pleased with how your cousin looks!

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