Placement of chromosomes from each parent on dna

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Discussion Overview

The discussion centers on the spatial arrangement of chromosomes in sexually reproducing organisms, particularly focusing on whether homologous chromosomes lie close to each other or are distant within the nucleus. The scope includes theoretical considerations and recent research findings related to chromatin organization during different cell phases.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested

Main Points Raised

  • Some participants question whether DNA from each parent exists as a single chain or if the strands lie side by side, with uncertainty about their joining.
  • One participant notes that during the G0 or G1 phases, DNA is wrapped around nucleosomes and exists as chromatin threads, suggesting that the organization of chromosomes is not straightforward.
  • Another participant mentions that new research indicates chromosomes are organized into "chromatin territories" during interphase, with some territories often lying next to each other, though this organization varies by cell type.
  • There is speculation about the organization of homologous chromosome territories, with one participant suggesting that territories of homologous chromosomes in mammalian cells are generally not adjacent.

Areas of Agreement / Disagreement

Participants express differing views on the spatial organization of chromosomes, with some suggesting that they are independent and not joined, while others propose that they may localize in specific territories. The discussion remains unresolved regarding the exact nature of the arrangement of homologous chromosomes.

Contextual Notes

The discussion highlights limitations in understanding the spatial organization of chromosomes, including the dependence on cell type and the phase of the cell cycle. There are also unresolved questions about the implications of chromatin territory organization on gene expression.

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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??
 
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ARAVIND113122 said:
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??

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:
mishrashubham said:
DNA in the G0[/sun] 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.


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
 
Ygggdrasil said:
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

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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