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    Michael Lerman said:

    This is clear evidence the genome is not sequenced yet. Michael Lerman, M.D., Ph.D.

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    Manoj kumar s said:

    @ Dr.Lerman:

    Your comment appears to be misleading. Perhaps, you wanted to mean that the assembly is still incomplete, which most of us will agree, including the curators and this author.

    Sequencing a piece of DNA is not a challenge; but putting them together in the same order as it is in the original genome is the real catch.

    The highly repetitive regions of the genome pose a major hurdle during the assembly process because the sequenced fragments from these regions are almost always smaller than the repeat itself, and so they collapse during algorithmic overlap.

    This is merely the inability of the sequencing platform to retain the order of the repeat elements, which is an additional information for a sequencing exercise. These repeats pose severe resistance to decipher even to the cloning based approaches.

    The sequences corresponding to these gaps are already there in the sea of data, which we have accumulated so far. But it is the missing information i.e. the length of the repeat segments, that eludes gap closure.

    Surely, the rapidly evolving sequencing technologies will be able to capture this “recalcitrant” repeats “as they are” in the near future, and seal the assembly problem once and for all.

    The present update (GRCh38) to the existing reference (GRCh37), after nearly four years, tries to tackle exactly the above discussed problem. The curators have refined the assembly and addressed the centromere problem, which is a commendable work.

    At this juncture, it is important to appreciate this development and the significance its holds for biomedical research rather than appearing less optimistic. Now is the time to get excited !!

    Happy New Year 2014 !!

    Manoj kumar s
    B.Tech, Industrial Biotechnology
    manojsbiotech [at] gmail [dot] com