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Author Topic: If identical twins marry identical twins, will their offspring be identical?  (Read 19272 times)

Russell Erasmus

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Russell Erasmus asked the Naked Scientists:

Hi Chris
 
I am a keen listener from South Africa and follow your show on 702.
 
My twelve year old asked me a question which is a bit more in your line of expertise:
 
"....if identical twins marry identical twins and both couples have babies of the same sex will the respective babies be identical..??..."
 
If possible can you answer via this email address to me
 
many thanks
Russell Erasmus

What do you think?


 

Offline RD

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With the exception of identical (monozygotic) twins, triplets, etc, each child receives a different mixture of genes from each parent,
(if this were not the case all siblings would be identical).

So the children of one couple would not be identical to the children of the other couple.

Genetically these cousins would be like siblings, so they would be unusually similar cousins, but not identical.
 

Offline iko

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With the exception of identical (monozygotic) twins, triplets, etc, each child receives a different mixture of genes from each parent,
(if this were not the case all siblings would be identical).

So the children of one couple would not be identical to the children of the other couple.

Genetically these cousins would be like siblings, so they would be unusually similar cousins, but not identical.

I think Russell was referring indeed to identical twins... ;)

http://images.google.it/imgres?imgurl=http://www.sciencemuseum.org.uk/on-line/genes/images/1-3-4-2-2-2-0-0-0-0-0.jpg&imgrefurl=http://www.sciencemuseum.org.uk/on-line/genes/118.asp&usg=__weLNVfbvEEq_xRKZdeTCRZFp7f8=&h=360&w=360&sz=23&hl=it&start=16&um=1&tbnid=cdalB4o4xOubAM:&tbnh=121&tbnw=121&prev=/images%3Fq%3D%2522identical%2Btwins%2522%26um%3D1%26hl%3Dit%26sa%3DG

« Last Edit: 19/12/2008 21:48:01 by iko »
 

Offline Counterpoints

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Interesting question!  Intuitively, you can see the answer is likely to be "no".  If the answer to your question were an unconditional "yes", wouldn't two brothers always be the same?  We know this isn't true.  You basically have two identical couples each producing offspring, in the situation you describe.  From a genetic standpoint, this is absolutely no different than having one normal couple producing offspring.  This is very important to realize.
« Last Edit: 12/07/2009 19:36:33 by Counterpoints »
 

Offline thedoc

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