Chromosome Differences

Genetics as it applies to evolution, molecular biology, and medical aspects.

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Hannamerika
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Chromosome Differences

Post by Hannamerika » Wed Sep 03, 2014 6:04 am

I am doing a very basic study of genetics/DNA and I finally figured out that the chromosomes are different size and shape because they are made up of different genes, but what I cannot discover is when/how and why the long DNA strand breaks apart to form the chromosomes. Any help?

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jonmoulton
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Re: Chromosome Differences

Post by jonmoulton » Wed Sep 03, 2014 3:06 pm

The DNA is never connected into a long single molecule in human cells. The DNA remains distributed into the 23 pairs of chromosomes (plus the mitochondrial chromosome), each single DNA molecules complexed with proteins. Each chromosome is replicated and then the chromosomes separate as a collection of different DNA strands during cell division, all without combining into a single DNA strand. Your genes are scattered about these different DNA molecules.

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Post by Hannamerika » Wed Sep 03, 2014 3:30 pm

Don't at least a lot of writings talk about this super longgggggggggggg strand of DNA? Making people like me wonder how this long strand gets broken into 23 separate pieces?

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Post by josem » Wed Sep 03, 2014 8:47 pm

I thing handling of large DNA molecule or chomosome may be difficult during replication or mitosis, so small DNA molecule selected during the course of evolution. We can see chromosomes number is usually increased from lower to higher eukaryotes or lower to higher complexity of genome.
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Post by Hannamerika » Wed Sep 03, 2014 11:38 pm

My mistake. I had been reading so much about this huge long strand of DNA I had to wonder when it breaks apart to form chromosomes. DUH, we get it broken apart in the first place:) But you have to admit it would be easy to think it is one long strand that goes for miles by the way it is often portrayed. Thanks for answering my question.

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Post by josem » Thu Sep 04, 2014 10:15 pm

Long chromosomes brake apart accidentally and selected eventually during evolution.
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