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<HTML> <HEAD> <TITLE>Re: [Zbrafish] Zebrafish Age / Size Variations;</TITLE> </HEAD> <BODY> FYI:  For discussion of relationships between between sexual differentiation, body length, and age, see: Maak H, Segner CR, and Tyler R (2003) Ontogeny of sexual differentiation in different strains of zebrafish (Danio rerio). Fish Physiology and Biochemistry, Volume 28, Numbers 1-4, 2003 , pp. 125-128(4). Chris On 8/8/08 7:12 AM, "Philippe Herbomel" <herbomel@pasteur.fr> wrote: <BLOCKQUOTE>Sorry, please replace my previous message (in which the reference of the book wasn't quite accurate) by this one. Philippe Herbomel Dear Oliver, Body length appears indeed to be the adequate, simple parameter for estimating postembryonic developmental stage. Our reference in this matter is Tom Schilling's excellent chapter on "The morphology of larval and adult zebrafish" (pp. 59-94 In "Zebrafish: A Practical Approach." 2002, eds. C. Nusslein-Volhard and R. Dahm, Oxford Univ. Press), in which Table 2 provides a typical correspondence between "age" and body length" up to 90 days. In their study of the development and maturation of the immune system in zebrafish, Lam et al. ( Dev. Compar. Immunol. 28 : 9-28, 2004) also described this maturation relative not only to age but also to body length (see Discussion), which is obviously more significant and helpful. You will see that they give the same correspondence between age and body length as Tom Schilling at 2 weeks but not at 4 weeks. Interestingly, an older paper comparing the role of thyroid hormone in zebrafish (vs. axolotl) metamorphosis, i.e. their gradual transformation form larvae into juveniles, also used body length to express the developmental stages (Brown D., PNAS 94 : 13011-16, 1997). This is obviously an important issue, and certainly all zebrafish studies dealing with stages past the first week of development should refer to body length in addition to or instead of nominal age. Also, the community should agree about how to measure that length. In Figure 1 and Table 2 of his chapter refered above, Tom Schilling provided two different measurements : 'Full length' i.e. up to the tip of the caudal fin, and 'standard length', ie up to the base of the caudal fin. I wasn't at the last Madison meeting but since there was a workshop there about "working with post-embryonic stages", maybe this staging issue was raised ? I would be interested to learn about this from participants to this workshop. Best wishes, Philippe   ––––––––––––––––––––––––––––––––––––––––– Philippe Herbomel Unite Macrophages et Developpement de l'Immunite Departement de Biologie du Developpement Institut Pasteur 25 rue du Dr Roux, 75724 Paris cedex 15, France tel. : 33 1 44 38 95 29 mobile: 33 6 73 35 74 20 fax : 33 1 45 68 89 21 <a href="http://www.pasteur.fr/recherche/RAR/RAR2006/Mdi-en.html">http://www.pasteur.fr/recherche/RAR/RAR2006/Mdi-en.html</a> –––––––––––––––––––––––––––––––––––––– Change the world one loan at a time - visit Kiva.org to find out how   Le 7 août 08 à 21:02, Oliver Braubach a écrit : <BLOCKQUOTE>Dear All. I have been working on aspects of postembryonic development in the zebrafish brain, and have been trying to determine a standard method for 'aging' zebrafish. As many of you may be aware, the development of individual fish varies greatly during the first month of development, which ultimately leads to very noticeable differences in the size of individual fish and their organs. Thus, age does not accurately characterize developmental stages of fish, and I have been trying to determine if there's another standard method to do so. Has anyone tried to correlate body length to fish age? Are there any citations for expected / optimal size of fish are a certain age? Any input regarding this problem would be greatly appreciated. Best, Oliver Braubach Department of Physiology and Biophysics Dalhousie University Halifax, NS B3H 1X5 Canada Tel: 902.494.6471 Fax: 902.494.1685 _______________________________________________ Zbrafish mailing list Zbrafish@net.bio.net <a href="http://www.bio.net/biomail/listinfo/zbrafish">http://www.bio.net/biomail/listinfo/zbrafish</a>   </BLOCKQUOTE> <HR ALIGN=CENTER SIZE="3" WIDTH="95%">_______________________________________________ Zbrafish mailing list Zbrafish@net.bio.net <a href="http://www.bio.net/biomail/listinfo/zbrafish">http://www.bio.net/biomail/listinfo/zbrafish</a> The information transmitted in this electronic communication is intended only for the person or entity to whom it is addressed and may contain confidential and/or privileged material. Any review, retransmission, dissemination or other use of or taking of any action in reliance upon this information by persons or entities other than the intended recipient is prohibited. If you received this information in error, please contact the Compliance HelpLine at 800-856-1983 and properly dispose of this information. </BLOCKQUOTE> </BODY> </HTML>

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