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Genetic polymorphisms

  1. Oct 23, 2013 #1
    I am in a query ,how genetic polymorphisms occur in genome of populations ??
    is it a sort of cross linking during meiosis or it occur during gametogenesis ??
    polymorphisms means multiple variants of the same gene , so if the genes are variants ,will this affect the function of the protein that is transcribed or any ALTERED phenotypic effect ?
    although the difference between every indiviual is the polymorphisms in DNA (0.5%) ONLY !
  2. jcsd
  3. Oct 23, 2013 #2


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    Here we try to answer confusions or difficulties that have arisen while studying. We don't write the textbooks which you sound like needing.

    Briefly the the context you are meeting them the polymorphisms can be called pre-existing in a population.

    You have probably noticed yourself directly that not all individuals in populations are identical.

    The genetic differences have arisen in cells in the germ line which came to differ from their ancestor by the process called mutation. This arises through faulty copying of DNA during DNA replication. The replication machinery has numbers of mechanisms for sole purpose of stopping this happening, but something gets through. Or the DNA was damaged before replication by external agents, radiation, chemical agents (and has got through the repair processes that try to limit that too). Most of the polymorphism seen has arisen many generations ago, but in a large population new mutations can be seen from one generation to the next; for just a few exceptionally highly varying genes it can even be seen from one generation to the next in most individuals.

    What is the mechanism(s) of mutation? In your first book you will find a few pages on it, in your second book you will find a chapter of two on it, later on you can find a book on it, after that you can find reviews of advances in it, you can find scientific journals entirely devoted to it, but you will find scientific papers and articles much concerned with it over a wide range of biology, molecular biology, cell biology, cancer research, medical and population genetics, certain environmental and public health research etc., it is woven through the whole lot.

    So don't mind me not have given a complete answer to your question. :biggrin: good luck with your studying.:smile:
    Last edited: Oct 23, 2013
  4. Oct 24, 2013 #3
    so if ti is an result of mutations over several years why human races do not differ from each other ,
    mean to say that when two or more clearly different phenotypes exist in the same population of a species so what are the different phenotypes in human ??
  5. Oct 25, 2013 #4


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    Well you do know that with exception of identical twins etc. all humans are genetically non-identical but they can all interbreed, and similarly for nearly all other animal species, indeed this is almost the definition of species. When members of animal populations become too different they can no longer interbreed and separate into different species.

    If you are asking how the species became separate you are again asking about a major theme of general biology and ongoing research and I repeat at this site we don't write the books, we at most try to help answering compression difficulties arising in the minds of those trying to study the books, particularly as revealed by difficulties in solving the exercises the textbooks provide.

    So for such general starting questions you should find another site. Better, read some general introductory books on genetics, evolution etc. For a quick answer to your questions I can only recommend you google 'mutation' and 'speciation'.
  6. Oct 25, 2013 #5
    SNPs can absolutley affect protein function. Think about the big push for personalized medicine these days and that's bound to come in the future. SNPs can significantly impact the way you metabolize drugs and their safety windows.

    http://www.cancer.gov/cancertopics/understandingcancer/geneticbackground/page13 [Broken]
    Last edited by a moderator: May 6, 2017
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