Placement of chromosomes from each parent on dna

In summary, the conversation discusses the organization of DNA in sexually reproducing organisms and whether homologous chromosomes lie close to each other or far apart. The current understanding is that DNA in the G0 or G1 phases is in the form of tangled chromatin threads, and homologous chromosomes are not joined together. However, recent research suggests that chromatin territories exist within the nucleus and homologous chromosomes may be located next to each other. Further research is needed to fully understand the organization of homologous chromosomes and its impact on gene expression.
  • #1
ARAVIND113122
54
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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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  • #2
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.
 
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  • #3
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
 
  • #4
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.
 
  • #5


In sexually reproducing organisms, the DNA is arranged in a double helix structure, with two strands of DNA running parallel to each other. Each strand contains a sequence of nucleotides that make up the genetic code. During sexual reproduction, each parent contributes one set of chromosomes, which contain the DNA, to the offspring. These chromosomes are arranged in pairs, with one chromosome coming from each parent.

The two strands of DNA do not lie side by side without joining. Instead, they are connected by hydrogen bonds between complementary base pairs (adenine with thymine, and guanine with cytosine). This allows for DNA replication and the accurate transmission of genetic information to the offspring.

The placement of chromosomes from each parent on DNA is random and not predetermined. During cell division, the chromosomes from each parent are randomly distributed to the daughter cells, ensuring genetic diversity in the offspring. Therefore, homologous chromosomes may lie close to each other or be distant from each other, depending on chance.

In summary, the two strands of DNA in sexually reproducing organisms are not separate and joined at some point, but rather they are connected by hydrogen bonds and form a double helix structure. The placement of chromosomes from each parent is random, resulting in homologous chromosomes lying close to each other or being distant from each other. This allows for genetic diversity and ensures the accurate transmission of genetic information to the offspring.
 

1. How are chromosomes placed on DNA?

The placement of chromosomes on DNA is determined by a process called chromosomal crossover. During this process, the chromosomes from each parent exchange genetic material, resulting in a combination of DNA from both parents on each chromosome.

2. Why is the placement of chromosomes from each parent on DNA important?

The placement of chromosomes from each parent on DNA is important because it ensures genetic diversity in offspring. This allows for a greater variety of traits and adaptations, increasing the chances of survival in changing environments.

3. Can the placement of chromosomes on DNA change?

Yes, the placement of chromosomes on DNA can change through a process called genetic recombination. This is when DNA is exchanged between non-homologous chromosomes, resulting in a different placement of genetic material on the chromosomes.

4. How does the placement of chromosomes on DNA affect inheritance?

The placement of chromosomes on DNA plays a crucial role in inheritance. It determines which traits are passed down from each parent, as well as the likelihood of certain traits being expressed in offspring.

5. Is the placement of chromosomes on DNA the same in all organisms?

No, the placement of chromosomes on DNA can vary between different organisms. For example, some species may have a different number of chromosomes or a different arrangement of genetic material on their chromosomes compared to others.

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