Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Why does the genetic composition of sex cells of an individual vary ?

  1. Jun 23, 2012 #1
    Why does the genetic composition of sex cells of an individual vary since the genome of an individual is same throughout his/her body.
  2. jcsd
  3. Jun 24, 2012 #2
  4. Jun 26, 2012 #3
    The genetic code in each somatic cell of a eukaryote organism is identical due to mitosis. This is cell division that reproduces the genetic code of a cell. Mitosis produces new cells with copies of each chromosome, one for one.
    Germ-line cells produce gametes by meiosis. This is a type of cell division that shuffles the chromosomes, shuffles some of the genes in each chromosome, and produces new cells (gametes) with half the chromosomes and half the genes of the original germ-line cells.
    Note that the term sex cell is ambiguous. The gametes are the haploid cells that fuse to form the zygote. Gametes can include both sperm cells and ova cells. The term germ-line cells is sometimes used for the diploid cells that produce the gametes through meiosis.

    Here is a link to an article on meiosis.

    Whilst the process of meiosis bears a number of similarities with the 'life-cycle' cell division process of mitosis, it differs in two important respects:
    the chromosomes in meiosis undergo a recombination which shuffles the genes producing a different genetic combination in each gamete, compared with the co-existence of each of the two separate pairs of each chromosome (one received from each parent) in each cell which results from mitosis.
    the outcome of meiosis is four (genetically unique) haploid cells, compared with the two (genetically identical) diploid cells produced from mitosis.”

    Here is a link to an article on mitosis.

    Mitosis is the process by which a eukaryotic cell separates the chromosomes in its cell nucleus into two identical sets, in two separate nuclei. It is generally followed immediately by cytokinesis, which divides the nuclei, cytoplasm, organelles and cell membrane into two cells containing roughly equal shares of these cellular components. [1] Mitosis and cytokinesis together define the mitotic (M) phase of the cell cycle—the division of the mother cell into two daughter cells, genetically identical to each other and to their parent cell. This accounts for approximately 10% of the cell cycle.”
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook