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Placement of chromosomes from each parent on dna

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  1. Mar 15, 2012 #1
    is dna in a sexually reproducing organism one single chain with dna from one parent coming first,with the other parent's dna joining it as it ends.or do the two strands lie side by side,without joining.Or do they lie side by side and join at some point?

    the purpose of asking the question is to know whether homologous chromosomes lie close to each other or are distant from each other??
     
  2. jcsd
  3. Mar 16, 2012 #2
    DNA in the G0 or G1 phases is wrapped around nucleosomes and exists in the form of chromatin threads. This is a tangled mess; the chromosomes aren't neatly organised in rows and columns inside the nucleus, so saying that the chromosomes lie close together or far apart doesn't actually make sense. No homologous chromosomes are not joined together either; they are two different strands independent of each other.
     
    Last edited: Mar 16, 2012
  4. Mar 16, 2012 #3

    Ygggdrasil

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    New research actually suggests that the chromatin of different chromosomes are organized spatially within the nucleus. While the chromosomes do not display as much organization as they do when condensed during mitosis, during interphase, the chromosomes appear to localize to specific "chromatin territories" and researchers have often found that the territories of certain chromosomes often lie next to each other. The details of chromatin territory organization differ between cell types however. See the link at the bottom of the post for more details.

    I'm not sure if anyone has looked at how the territories of homologous chromosomes are organized. Perhaps following some links from the site below can shed some light on the issue.

    http://www.nature.com/scitable/topi...tories-the-arrangement-of-chromosomes-in-3025
     
  5. Mar 16, 2012 #4
    Intriguing! It'd be interesting to see how well defined these territories are and what effect this form of spatial organization within the nucleus has on gene expression. Also, according to this (link), territories of homologous chromosomes in mammalian cells are generally not adjacent.
     
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