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What is linkage strength between gene loci?

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  1. Apr 24, 2017 #1
    1. The problem statement, all variables and given/known data
    In linkage strength between any two gene loci is 70%,what would be the amount of crossing over between
    these loci?

    (a) 15% (b)30% (c) 70% (d) none of these.

    2. My approach at understanding the concept

    I didn't find much about linkage strength from any authentic source.
    I can think of two things :
    • The strength of a linkage would be greater if the spatial separation between two genes is less and the lesser if the separation is more. This is semantic. But,
    • how can it be represented in percentage? What does this 100 mean in this 70%? The separation between two genes can be more than 100 map units.
    3. Question in details

    What does linkage strength mean? How is it related to amount of crossing over?

    I would appreciate answers citing some authentic sources.
     
  2. jcsd
  3. Apr 24, 2017 #2

    epenguin

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    I suppose an authentic source would be the 600+ page 'Dictionary of Genetics'. It is not mentioned there. I have never heard the term used In a technical defined way; I suppose it can be used in a loose way io speaking. I do not understand how you can be asked such a question and are not supplied with a text that gives you a definition. I think genetic distances are usually expressed in centimorgans.

    I would just answer 30% and wait to see if your Prof. gives an explanation.
     
  4. Apr 25, 2017 #3
    I think it is not a standard term too, if so Google would have shown some results. It was in a question paper, not a homework.

    I also thought that way.
    But using the word linkage strength to mean amount (proportion) of offspring with parental combination of genes is a bit strange.
     
  5. Apr 25, 2017 #4

    epenguin

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    One usually hears of closeness of linkage rather than strength.
     
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