In response to a point in the message of Dr. Muir [7 September],
The problem is that it is possible to test a fish for triploidy, not for sterility. The fact that a few (or large) number of triploids could be fertile is not demonstrated in salmonids but can be observed in other species (misgurnus, poeciliopsis).
At 04:54 PM 9/7/00 +0200, Bill Muir wrote:
>I totally agree with Dr. Benfey's suggestion [7 September] that every
>transgenic salmon be
>tested for sterility before rearing in net pens.
Bernard CHEVASSUS
Laboratory of Fish Genetics
INRA.78350 JOUY FRANCE
Phone 33 (0) 134 652 328
fax 33 (0) 134 652 390
mobile phone 680 368 412
e-mail: bchevass@diamant.jouy.inra.fr
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-----Original Message-----
From: Biotech-Mod4
Sent: Monday, September 11, 2000 3:58 PM
To: 'biotech-room4@mailserv.fao.org'
Subject: Re: Sterility techniques
Dr. Chevassus [11 September] makes a good point that triploidy is not necessarily the same as sterility. Another factor that I overlooked in my discussions is that triploid male salmon are still sexually active, even though they may not be capable of fertilizing eggs. This results in a different kind of risk, depending on the numbers released and how often. Releasing sterile males is a method of bio-control used to eradicate some insect species. If sterile males mate with fertile native females, the reproductive efforts of the females are wasted. If enough males are released, a significant decline in population numbers of native fish will result. Thus, in addition to making the fish triploid (and testing for sterility if necessary), the males need to be sex reversed. Although I have heard of sex reversal being done successfully in salmon, I haven't seen the data on effectiveness, and numbers tested.
Bill Muir
Professor of Genetics
Department of Animal Sciences
Purdue University
W. Lafayette, IN 47907-1151, USA
Phone 765-494-8032
FAX 765-494-9346
E-mail Bmuir@purdue.edu
http://www.ansc.purdue.edu/faculty/muir.htm
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-----Original Message-----
From: Biotech-Mod4
Sent: Monday, September 11, 2000 5:37 PM
To: 'biotech-room4@mailserv.fao.org'
Subject: Transgenic fish (GMOs) and sterilitization techniques
This is from Professor Mork, Norway.
Concerning transgenic fish (or genetically modified organisms (GMOs)) risk management and the efficiency of various sterilization techniques in fish - here are some additional sources of information and arguments:
Both of these themes have been treated by the WGAGFM (Working Group on the Application of Genetics in Fisheries and Mariculture) of the International Council for the Exploration of the Sea (ICES) in several annual terms of references and meetings since 1995: (Transgenic Fish: 1995, 1996, 1997, 1998 and Triploidy/Sterility: in particular 1995 (but see also 1999)).
The results from these discussions of the Working Group, as well as the WGAGFM recommendations to ICES, are found at the WGAGFM Homepage under "Reports". They are in Word format and can be found on http://www.dfu.min.dk/ffi/wgagfmweb/index.htm
In short:
The WGAGFM discussion on the efficiency of various sterilization techniques
was triggered by the alarming experiences with Pacific oysters transferred
to the US east coast as triploids. Unexpectedly, the animals showed a high
frequency of return to a diploid state. The WGAGFM report of 1995 concludes
that no current mass triploidisation/sterilisation technique is guaranteed
100% effective.
The WGAGFM discussion on transgenic fish resulted in a conclusion that, until further, transgenic fish should be managed by the same strict rules as those that apply to exotic species (which is regulated by the ICES Code of Practice on the Introduction and Transfer of Marine Organisms 1994 (maybe with later updates).
Prof. Jarle Mork
Biological Station, Bynesveien 46
N-7018 Trondheim, Norway
Phone: (+47) 73 591589, Fax: (+47) 73 591597
Internet: www.ntnu.no/~jmork/jmork/morke.html
e-mail: JARLE.MORK@VM.NTNU.NO
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