How many chromosomes do humans have ?

[Geir19]

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 ?!

 

[jim mcnamara]

The DNA in a mitochondrion is circular like the DNA in bacteria.
Humans have 46 chromosomes in pairs, so we really have 23 chromosomes. 22 are somatic chromosomes and one is a sex chromosome - either X chromosome or Y chromosome.

IMO circular does not count as a chomosome, aside from the fact that a single cell can have many mitochondria, each with its own copy of DNA.

 

[quicknote]

I can confirm that humans typically have 46 chromosomes in their cells. This is made up of 23 pairs of chromosomes, with one set inherited from each parent. However, there is some variation in the number of chromosomes among individuals due to genetic mutations or chromosomal abnormalities.

The statement that humans have 47 chromosomes is partially correct. While we do have 46 nuclear chromosomes, we also have one mitochondrial chromosome. This is a small, circular piece of DNA found in the mitochondria, which are the energy-producing organelles in our cells. The mitochondrial chromosome contains genetic information that is essential for the proper functioning of the mitochondria.

While the mitochondrial chromosome is technically considered a chromosome, it differs in structure and function from the nuclear chromosomes. It is much smaller and contains a different set of genes. The nuclear chromosomes carry the majority of our genetic information and are responsible for traits such as eye color, height, and susceptibility to certain diseases. On the other hand, the mitochondrial chromosome primarily codes for proteins involved in cellular respiration.

In summary, humans have 46 nuclear chromosomes and one mitochondrial chromosome. While the mitochondrial chromosome is considered a chromosome, it differs in structure and function from the nuclear chromosomes. As scientists, we count it as a chromosome due to its role in our genetic makeup and cellular function.