As I understand it, each nucleus of a cell contains multiple chromosomes. Each chromosome has multiple DNAs. Each DNA contains some specific gene sequences. That sequence is called Genome.

My question, do all chromosomes in cells in a human body contain same types of genomes (i.e. gene sequences)?


marked as duplicate by MattDMo, WYSIWYG Dec 8 '16 at 8:24

This question has been asked before and already has an answer. If those answers do not fully address your question, please ask a new question.

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    $\begingroup$ About your first paragraph, a correct phrasing would be "Each nucleus contains multiple chromosomes, each chromosome contains 2 strands of DNA (although it depends on the timing in the life-cycle). The genetic information is in the sequence of amino acids that make up the DNA. DNA. The genome is the entire genetic sequence of an individual." $\endgroup$ – Remi.b Dec 2 '16 at 5:01
  • $\begingroup$ @Remi.b, where does the gene stand in your description? $\endgroup$ – user28169 Dec 2 '16 at 5:08
  • $\begingroup$ A gene is a vaguely defined functional unit of the genome :). It corresponds to a given locus (position on the genome) and often contain a coding region (a coding region is a sequence which is translated and transcribed into protein). Have a look at wikipedia for more definitions. As everyone can see the comments, I edited your post to remove your copy-paste of my comment. $\endgroup$ – Remi.b Dec 2 '16 at 5:11
  • $\begingroup$ @Remi.b, how is my question a duplicate here? I couldn't figure it out !!!!???? $\endgroup$ – user28169 Dec 2 '16 at 5:13
  • $\begingroup$ You are correct, the post I linked is not a duplicate. Sorry about that, I'm removing it. $\endgroup$ – Remi.b Dec 2 '16 at 5:55

Yes, all cells contains the same genome. This is because, for a given individual, all of its cells comes from the zygote, a singular cell formed after fecondation of the maternal ovum and paternal spermatozoa, through repeated cell division (mitosis). This is a process which replicates quite exactly the genome that will be passed to the newly formed cells.

There are some exceptions however, such as :

  • Red blood cells, and platelets : these cells lack a nucleus, and don't contain DNA at all.

  • Cells bearing mutation(s) : even though the replication machinery try to make an exact copy of the DNA, error(s) may happens.

  • Gametes : ovum and spermatozoa are produced through meiosis, a specific replication mechanism that keeps only half the genome, and may produce new sequences through recombination.

  • Lymphocytes undergo V(D)J recombination and somatic hypermutation which alters their DNA, a process that is necessary to the working of our immune system.