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The map is in the bag, but the sequence may yet reveal if kangaroos have jumping genes

Posted by Coturnix on November 19, 2008
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There is an utterly confusing press release out today – Australian First: Kangaroo Genome Mapped:

Australian researchers are launching the world first detailed map of the kangaroo genome, completing the first phase of the kangaroo genomics project.

Why is it confusing?

Because we are used to seeing press officers and media botch the terms. They often use the words “map” and “sequence” interchangeably.

Mapping a genome means locating genes on chromosomes, i.e., you get to know where each gene is on each chromosome. For this, you do not need to know the sequences of any genes, and certainly not the sequences of stuff between and around the genes.

Sequencing a genome means figuring out the exact order of all nucleotides in the entire DNA of the organism.

Some people do the mapping. Some do the sequencing. Some map first, sequence second. Others sequence first, map later. Some sequence most of the genome, then map it in order to put the last finishing touches on the sequencing, i.e., making sure that all the fragments are ordered correctly.

What appears that the Australian team did is that they mapped the Tammar Wallaby genome first. They intend to sequence it next year.

The source of confusion is the press release which does not state this clearly. Usually a press release reports on the research that is already done and published. In this case, the press release mixes together TWO statements – a) the map has been finished, and b) the sequence is on its way next year. The first is done, the second is yet to be done.

RPM and T. Ryan Gregory are trying to grapple with it all.

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Comments

  1. #1 Ian
    November 20, 2008

    “…the sequence may yet reveal if kangaroos have jumping genes”

    That was ba-ad! But in a good way.

  2. #2 Coturnix
    November 20, 2008

    I should have said that the map is in the pouch….

  3. #3 Andrew
    November 24, 2008

    If you understood how genomes are figured out then you wouldn’t have a problem Coturnix.

    1) A genome first cut up into pieces and sequenced (DNA ATCG code).

    2) The map is made of markers (not necessarily gene coding sequence) that are located along chromosomes – physically mapped to chromosomes. These markers are physically mapped to the chromosomes using a tecnique called FISH – fluro in situ hybridisation.

    Knowing where the markers go on the chromosome forms this map.

    From the sequencing step (1), you then align the markers from the sequence down according to the order they appear along the chromosome, you join the gaps between pieces and ‘Hey Presto!’ you’ve got yourself a genome.

    Think before you speak

    Andrew

  4. #4 Coturnix
    November 24, 2008

    ….which is one of the three strategies I noted above: sequence – map – finish sequence.

    Read before you speak.

  5. #5 stare gry
    November 25, 2008

    On a lighter side, it has not escaped my attention that humans still sport a pair of strong legs just as goats, cattle, kangaroos; consequently, humans could jump. The basketball players, soccer player etc., are adept in jumping; therefore, the genes controlling the muscle strength of legs in humans must have originated from kangaroo or the species that is the ancestor of Australian jumping marsupials. Try telling all these to a person who thinks that the biblical account of genesis is true. You surely will get a strange response.