How many chromosomes do humans have ?!

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Neuron
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How many chromosomes do humans have ?!

Post by Neuron » Thu Oct 01, 2009 2:00 pm

I have always known that humans have 46 chromosomes, but recently someone told me that we have actually 47 chromosomes. He said we have 46 nuclear chromosomes and one mitochondrial chromosome. Is this true?! Is this mitochondrial genetic information a real chromosome or does it differ in structure/function from the other nuclear chromosomes?! What does scientists say about it?! Is it counted as a chromosome ?!

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jonmoulton
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Re: How many chromosomes do humans have ?!

Post by jonmoulton » Thu Oct 01, 2009 3:40 pm

The mitochondrial chromosome is real, but differs in structure from the nuclear chromosomes. The mitochondrial chromosome resembles a bacterial chromosome.

http://en.wikipedia.org/wiki/Mitochondrion#Genome

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canalon
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Post by canalon » Thu Oct 01, 2009 9:14 pm

And it replicates independently from the other chromosomes, not in the nucleus but within the mitochondrion.
Patrick

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kolean
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Post by kolean » Thu Oct 01, 2009 10:49 pm

Just wanted to add that chloroplast in plant cells also have a DNA component in their genetic makeup.

Mitochondrial DNA is also from the maternal oocyte, as the sperm's mitochondria do not enter the oocyte (just the nucleus does) upon fertilization.

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