|December 2005||National Research Flagship||www.csiro.au|
DNA fingerprinting for superior prawns
Prawns, like most aquaculture species, are great candidates for achieving rapid gains through selective breeding. Their high fecundity generates a broad gene pool from which to select elite performers.
Tracking the pedigree and relative performance of individual prawn families in farm ponds, however, can be quite a challenge.
A fast, efficient way of identifying tens of thousands of family members is necessary to maximise the gains of selective breeding, and minimise inbreeding.
In response to this need, a project of the CSIRO Food Futures Flagship is developing DNA marker tests for black tiger prawns, (Penaeus monodon), as the industry progresses from wild-caught to domesticated broodstock.
Like people, all prawns have unique DNA fingerprints that pinpoint their pedigree.
DNA marker tests can be used to fingerprint the progeny of mixed-parent spawnings, so that family lines don’t need to be separated or physically tagged in production.
The Food Futures project is isolating and refining DNA markers known as microsatellites, an accurate technique used widely in human fingerprinting and agriculture.
These will form the basis of high-volume, rapid throughput testing systems to cope with the masses of prawns screened in commercial breeding programs.
The beauty of microsatellite markers is that they allow breeders to track the contribution of both female and male parents to the performance of prawn families, unlike mitochondrial markers which detect only maternal inheritance.
So they offer an efficient way to identify high-performing individuals and families, and to select the next generation of parents.
Microsatellite systems developed so far have proved successful in monitoring the genetic diversity of P. monodon founder stocks from various geographic regions. They are ready for testing the power of parentage identification in tanks and ponds.
Seeking growth genes
A second avenue of genetic research in support of selective breeding is delving deeper into the DNA of prawns.
The goal is to find candidate genes or groups of genes that control desired traits – such as growth, survival or disease resistance – and to use this information to select high-performing individuals.
So far the search has revealed a genetic region associated with growth variation in the Kuruma prawn (P. japonicus). Individuals differing at this region have marked differences in growth.
The next step is to identify the actual gene and its function.
Early indications suggest it may be a gene linked to fatty acid metabolism, an essential component in the growth process. Controlled tank environment experiments are under way to validate the influence of this genetic region on prawn growth.
This prawn growth genetics research is part of the Aquaculture Breed Engineering theme of the CSIRO Food Futures Flagship. The research aims to develop high performance, high quality breeds and sustainable production systems for the Australian prawn, salmon and abalone aquaculture industries. It involves scientists from Food Science Australia, CSIRO Livestock Industries and CSIRO Marine and Atmospheric Research.
more details on DNA fingerprinting of prawns:
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The Food Futures Flagship is a CSIRO initiative and part of the National Research Flagships program that aims to deliver scientific solutions to advance Australia's most important national objectives. One of the largest scientific initiatives ever mounted in Australia, it aligns closely with the Federal Government's National Research Priorities. The initiative brings together our national research resources to deliver breakthroughs in fields ranging from healthcare to light metals and the environment.
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