• Question: how far back can you trace one gene back and from one gene can you find out different family members

    Asked by rhino645 to Adam, Joanna, Louise S, Louise W, Marcus on 13 Nov 2012.
    • Photo: Adam Paige

      Adam Paige answered on 13 Nov 2012:

      You can trace a gene back a long way, by looking to see how many different people have that particular version of the gene. If lots of people have a particular version of a gene then that version must have formed a very long time ago in order for so many people today to have inherited it. It is not my area of expertise particularly, but it is this kind of work that made scientists realise how closely related all living things are.

      You can also tell if people are related from their genes. Looking for the same types of genes can show if someone is the parent of a particular child, or if two people are actually brothers or sisters. But generally you would have to look at more than one gene for this. Lots of unrelated people will have one gene the same. But if you look at many different genes, only close family members will share them all.

    • Photo: Louise Stanley

      Louise Stanley answered on 13 Nov 2012:

      Sometimes at my work we get asked to find out if two people are related to one another. We do this by looking at something called microsatellites – these are short repetitive bits of DNA – which tend to be different between people. We look at lots of these across the genome and the more similar the results that we get the more likely that two people are related. It is often referred to as DNA fingerprinting. Programs like CSI do this kind of work all the time to find the criminal or badie – so it does get done in real life but it takes a lot longer than they show on the program!

    • Photo: Marcus Wilson

      Marcus Wilson answered on 14 Nov 2012:

      Lots of genes can be compared between very different species. you would be surprised the number of genes we share with things as simple as single-celled yeast. fundamental biological processes are very well conserved so so too are the genes.

      The genes themselves have often changed slightly between orgnaims as they both evolve. This helps us to tell what part of a gene is critical and must stay the same and what part can tolerate some changes.

    • Photo: Louise Walkin

      Louise Walkin answered on 19 Nov 2012:

      Yes, genes can be traced very far back. Like Marcus says, genes can be compared to many different species as well. Half our DNA is shared with bananas! 🙂

Comments

  • Photo: Louise S

    Louise S commented on :

    As bit on an extra… To carry out family tree studies using DNA it is also possible to look at mitochondria DNA as unlike all your other DNA this is only inherited from your mother (this looks at maternal side of the family) and to look at the paternal or Dad’s side of the family we look at the Y chromosome as this is unique to males.