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Thread: Mendel and hamiltons rule.

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    Senior Member Greengage's Avatar
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    Default Mendel and hamiltons rule.

    I was reading up on some past papers from the senior scientific programme and one question was.
    “A queen bee is genetically identical to her workers” – discuss the accuracy or otherwise of this statement. Include Mendel’s Laws and Hamilton’s rule in your discussion.
    Any suggestions where I would start with this. Ok Bees have a different number of chromosomes. Females, workers and queens have 32, 16 are contributed by the queen's eggs and 16 come from the drones sperm. A fertilised egg can only carry half of the queens 32 chromosomes so she can only pass on half of her genes to her offspring. Each egg laid by the queen contains a unique collection of her genes, so each egg is different. Drones on the other hand only have 16 chromosomes because it is an unfertilized egg. I don't know maybe I should answer another question.

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    Administrator gavin's Avatar
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    You'd get some points for that but also the comment: 'Could do better'. A lot.

    Queens are not genetically identical to their workers, the statement was fully inaccurate. That gives you a clue for the rest of the answer but it is worth stating clearly your answer to the question rather than beating around that bush. You know why they're not but didn't clearly state it. Workers have a mum and a dad, the dad introduces new genetics not in the queen's own cells.

    As a card-carrying geneticist (lapsed) I had to look up Hamilton's rule. It is about kin selection theory. It is OK to look after other folk's babies when you're related to them unless your own output of babies is affected. Workers have little chance to make their own (sometimes there may be an opportunity to make a drone) so they might as well help mum out by looking after hers. In many cases they're half sisters and in some cases (when dad was the same) they will be full sibs. Much has been speculated about whether or not workers can discriminate (and discriminate against) half-sibs versus full sibs.

    To score points on the Mendel thing I would think that you'd also have to describe the behaviour of single genes such as Aa (queen) x A (drone) to Aa and AA (queens or workers) in a 1:1 ratio and how that might differ for a different patriline (A1, A2, A3, whatever).

    To get all the points, read the question carefully. You were asked: 1) was the statement accurate?, 2) work in Mendel's laws to your answer, 3) work in Hamilton's Rule to your answer. You need to address all three.

    I say all this with very little knowledge of the various bee examination systems other than I managed to pass the SBA's Basic a few years ago.

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    Senior Member Greengage's Avatar
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    Ok thanks Ill do a bit more study (A Lot) and have a go probably in a couple of months. Genetics is complicated, Maybe the person setting the question didn't fully understand it themselves but that might be unfair on my part. In an exam there should not be trick questions like this. Thanks again I will come back to this when I get my head around it.

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    Senior Member fatshark's Avatar
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    A pedant might suggest that an introduced queen might be totally unrelated to the workers in the hive. It's a moot point perhaps whether they were then 'her' workers ... does 'her' indicate parentage or just that they work for her?

    Treat this answer with caution as I've not even passed the SBA Basic, though I've got something similar(ish) from South of the Border.

    I don't think it's a trick question. As Gavin indicates it's reasonably well structured - it makes a statement, requests whether it's factual or not and then gives a strong steer as to what needs to be included in the answer for full marks.

    Interesting to speculate how Hamilton's rule would apply to A. mellifera capensis where the workers can lay diploid eggs that can be raised to make more workers or queens ... 'worker laying workers'.

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    Quote Originally Posted by fatshark View Post

    Interesting to speculate how Hamilton's rule would apply to A. mellifera capensis where the workers can lay diploid eggs that can be raised to make more workers or queens ... 'worker laying workers'.
    Ahh but the original question was relationship to queen.....
    So as the workers are all derived from the queen...
    Okay you are right :-)

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    Senior Member Greengage's Avatar
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    I had another go at this question, How do you think I am doing??
    Q. A queen is genetically identical to her workers discuss the above statement.

    The Queen honey bee is female she has 32 chromosomes as she is diploid. (Two sets of chromosomes)
    The worker honey bee is female she has 32 chromosomes.(Two sets of chromosomes)
    A Male honey bee is haploid he has 16 chromosomes (One set of chromosomes.)
    During egg production in the queens ovaries meiosis occurs that is the reduction of cells by half to produce four gamete cells, this leads to 16 chromosomes in each egg.
    If the egg is fertilised it will have 16 chromosomes from the male and 16 chromosomes from the female, the resulting off spring will be female and will have half her genetic make up from her father and half from her mother.
    The new female (Daughter) will have 50% of her mothers genes therefore they are not identical. Hamilton’s rule is used to measure genetic relatedness for the queen and daughter here they are related by 50%.
    A Male (Drone) receives all of his genes from his mother the Queen he shares 100% of his genes with his mother. He is haploid that is he has 16 chromosomes. During meiosis the queen only passed on 50% of her genes to the male she is only related to him by 50%. It also means that the male has no father and received none of his genes.
    If the queens eggs are all fertilised by one particular drone then all the sperm will be genetically identical, Workers born from these fertilised eggs will have 50% of the queens genes and 100% of the males genes therefore the workers will be related to each other by 75%. That is 100% related to their fathers and 50% related to their mothers.
    If each sister receives one of two possible sets of chromosomes from her mother (Queen) and these are half her genetic make up then there is a 50% chance that 50% of her genes will be the same as her sisters. If both sisters get the same genes from the same father then half of the genes are exactly the same, these workers are then known as super sisters.
    As queens mate with multiple drones Approx 15 workers born from a fertilised egg could have different fathers these workers will have 50% genes from mother and 100% of drones genes but since all drones are different, the females will be only 25% related and are half sisters.
    This means that sisters (workers) are more related to each other than they are to their mother, father or any daughters they could produce. So if a worker wanted to pass on her genes it would be better to do it through her sisters who will be raised as queens as they will have 75% of her genes. If a worker could have a daughter they would have 50% of here genes.
    Therefore the above statement is not correct.

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