chromosome counts

From: Pieter Folkens (animalbytes@earthlink.net)
Date: Wed Mar 19 2003 - 21:34:16 EST

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    On Tuesday, March 18, 2003, at 01:37 PM, Joe Tanzola wrote:

    > What animal has the highest chromosome count?

    There is variation in chromosome counts of animals going from the most
    simple, single-celled animals (with few chromosomes) on up to the
    highest vertebrates. Since this program focuses on whales, I will focus
    the answer to your question on that subject. (With thanx to Scott Baker
    for some details)

    There is a good overview of cetacean chromosomal variety in Rice
    (1998). Cetaceans overall have a very conserved karyotype (compared
    for example to ungulates). The Balaenopteridae have 2n = 44 and
    Balaenidae 2n = 42. For Odonotoceti, again the general is 2n = 44 but
    some beaked whales have 2n = 42. The sperm whale also has 2n = 44 but I
    think that the reduction is for different reasons in each case (i.e.,
    the 2n = 42 for sperm if not the same as beaked whales). Debbie
    Duffield did most of the early work on karyotyping along with Arnason.
    There are several species that have yet to be karyotyped (including
    many beaked whales and the pygmy right). Below is the only reference
    for the humpback.

    Lambertsen, R. H., C. S. Baker, D. O. Duffield, and J. Chamberlin-Lea.
    1988. Cytological determination of sex among individually identified
    humpback whales (Megaptera novaeangliae). Can. J. Zool. 66:1243-1248.

    If you would like to look further into this subject, I'll direct you to
    the following web site:

    > whale and dolphin identification website
    > http://www.dna-surveillance.auckland.ac.nz/
    >
    > website of the Molecular Ecology and Evolution Laboratory
    > http://www.sbs.auckland.ac.nz/research/ecolevol/index.htm
    > select Molecular Ecology and Evolution

    Cheers,

    Pieter Folkens
    Alaska Whale Foundation



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