Techniques to produce resistant lines of Pacific abalone, Haliotis discus
discus, to amyotrophia disease
M. Hara (Genetic Div)
To establish an evaluation method of genetic traits using mixed rearing
in abalone, microsatellite DNA markers for pedigree analysis have been
developed. It was shown that resistance to amyotrophia disease in juveniles of
abalone is related to the genetic character of spawners using microsatellite DNA
markers. This will be considered to contribute to the establishment of effective
selection techniques and solutions of the problem of mass mortality during seed
production in abalone called "Kuroawabi".
- [Objective]
- Mass mortalities of juvenile abalone, Haliotis discus discus,
have occurred frequently in many hatcheries. The development of resistant
lines using selection techniques have been considered to be one of the
effective methods. The aim of this research program is the establishment of an
evaluation method of genetic traits using the microsatellite DNA markers for
pedigree analysis. That is, the development of a method to estimate the
genetic variation of abalone reared in the same rearing environment is goal.
And, comparing with the families survived of the disease and the families
produced by natural abalone, the resistant line have been attempted to be
confirmed.
[Results]
- The 71 microsatellite DNA regions of abalone were isolated, and the
variability and the Mendelian transmission of these regions were checked. 14
microsatellite DNA markers were developed as useful markers for pedigree
analysis.
- In abalone seed that were mixed immediately after mating in one rearing
tank, we were able to identify the pedigree completely.
- During mass mortalities of juvenile abalone that occurred from May to
August, the composition of the seed produced by natural abalone were decreased
largely, while that of the seed produced by parental abalone that had survived
a previous infection by amyotrophia disease, increased remarkably. This
suggested that the survied abalone had genetic resistance to amyotrophia
disease, and were kept as breeding materials of the resistance.
- The analysis of parentage determination in hatcheries is expected to be
an effective method for researching useful breeding materials.
- [Publications]
- 1)M. Sekino and M. Hara (2001): Microsatellite DNA loci in Pacific
abalone Haliotis discus discus. Molecular Ecology Note, 1, 8-10.
2)M. Hara and M. Sekino (2000): Genetic and breeding science of abalone
and their application to the aquaculture techniques. SUISANZOSHOKU, 49(2),
123-126.
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