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Agriculture see Forum website.
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Sent: 20 June 2005 11:37
Subject: 62: Fish genetic resources - Malaysia
I am Subha, a research officer attached to the Department of Fisheries, Malaysia.
It is an interesting discussion raised in this conference. Biotechnology is indeed very important to address a problem in any area, whether it is plants, forestry, animal and lastly fishes. The discussion that has been held on the importance and its potential is indeed debatable. I have to say that it is a tool for most of us, but the impact of biotechnology in selective breeding, stock improvement and characterisation has taken off in fish.
The work done by Kocher's group in tilapia by isolating microosatellites and depositing in the gene bank, continued by creating linkage maps with the possible loci, helped us in my PhD where I screened almost over 100 microsatellite primers that they designed. It helped me to characterise the various red tilapia stocks that was used in the breeding (Bhassu et al, 2004). In the tilapia study, characterisation was done using allozymes then later continued with microsatellites. The results showed that most of the fishes were inbred and had low heterozygosity levels. The phenogram was the same using both kinds of markers. In terms of laboratory to laboratory problems, I had no problem as the same primers were also used by Mather's group in Australia. We even exchanged the primers annealing temperature condition. It all depends on how you look at it. [Publications from T.D. Koscher available at http://hcgs.unh.edu/Staff/kocher/kocherpubs.html ; The Bhassu et al reference is to Bhassu S, Yusoff K, Panandam JM, Embong WK, Oyyan S, Tan SG. 2004. The genetic structure of Oreochromis spp. (Tilapia) populations in Malaysia as revealed by microsatellite DNA analysis. Biochemical Genetics 42(7-8):217-29...Moderator].
In my personal experience, I know that many people use biotechnology as a tool to address many problems, but I feel with sound knowledge on genetics (population and quantitative), breeding plays more important role in improving stocks and for conservation. Take the giant freshwater prawns project - the culture of these prawns have increased rapidly. It is an alternative source of an economically important commodity that many developing countries are looking at. I have to congratulate Dr New who came out with concise information on the freshwater prawn farming in FAO. Did it spark interest among the breeders and geneticists? I would say, yes. I am collecting the various stocks from the various riverine sources looking at their morphology and genetic make up. The breeders in Malaysia, with collaborative efforts with the WorldFish Center, is looking at genetic stock improvement of this giant freshwater prawns. Geneticists in Thailand are also working on sex identification of this prawn using AFLP markers. This biotechnology information will indeed be of importance. Research information on morphology identification, molecular characterisation is done with selective breeding. Funding you may ask? Very little. But then efforts are being made to obtain financial support. [The reference is to New, M.B. 2002. Farming freshwater prawns: A manual for the culture of the giant river prawn (Macrobrachium rosenbergii). FAO Fisheries Technical Paper 428. (ftp://ftp.fao.org/docrep/fao/005/y4100e/Y4100E00.pdf or contact FI-Inquiries@fao.org for more information). The original manual on freshwater prawn farming was written by M.B. New and S. Singholka in 1982 and translated in several langauges...Moderator].
The recent publication by Mather 2004 has shown that M. rosenbergii (freshwater prawn) is classified into two form, the western and eastern forms. We need information that we can use, as now we know that Malaysian freshwater prawns are different from the Australian freshwater prawns. This information is indeed vital for prawn breeders when they want different stocks. Of course, the importance of phylogeny may be of no importance to a farmer, but people like me, being trained as a molecular geneticist and an officer in the Department of Fisheries, could advise the farmers of its impact of importing a divergent form of the same form like. [The reference is to de Bruyn, M., J.A. Wilson and P.B. Mather. 2004. Huxley’s line demarcates extensive genetic divergence between eastern and western forms of the giant freshwater prawn, Macrobrachium rosenbergii. Molecular Phylogenetics and Evolution 30:251-257. Their paper used 16S rRNA mitochondrial gene sequence data to confirm that there is an east-west grouping of the prawn, that had been noted before using morphological and allozyme data...Moderator].
The impact of biotechnology is very limited in fish, yet fantastic work has been done on the common carp and salmon. I hope the recent news like depositing of expressed sequence tags (ESTs) of the tilapia genome, headed by Kocher's group, will give advancement in our future marker assisted programs in tilapia in Malaysia and other countries.
Subha Bhassu, PhD
Freshwater Fisheries Research Center,
email: subhabhassu (at) yahoo.com
Sent: 20 June 2005 11:52
Subject: 63: Re: Molecular characterisation of animal genetic resources
I am Miguel A. Toro from the Department of Animal Breeding of INIA (Spain).
With respect to the message of Salah Galal (message 60, June 19), I would like to point out two things:
1) Establishing that two breeds are genetically similar does not guarantee that the genetic improvement program of one of them can be applied to the other, because this depends on the existence or not of genotype x environment interaction. For example, the Holstein is a universal breed but probably a different genetic improvement program should be implemented in a tropical or in a temperate climate.
2) I cannot see ‘exactly’ how molecular markers could be used to decide if two breeds are or are not the same. First: a) molecular markers refer to neutral or non-coding genetic variation; b) it is well known that genetic distances are not very useful in this context because they ignore within breed variation. An inbred line (just because a handful of animals became isolated in a small area during a few generations) would be classified as a very different breed despite not having interest at all.
3) I am not very sure that biotechnological approaches are being used in developed countries. For example, the genetic improvement program of dairy cattle in USA is considered highly competitive, but as far as I am aware, they are not using molecular information. Or am I wrong?
Miguel Angel Toro Ibanez
Departamento de Mejora Genetica Animal
Instituto Nacional de Investigacion y Tecnologia Agraria y Agroalimentaria (INIA)
Carretera La Coruna km. 7 28040 Madrid
Telf: 34 913476807
Fax: 34 913572293
e-mail: toro (at) inia.es