Applications of DNA Microsatelite Markers Intilapia Culture
In Malaysia, the role of aquaculture in fish production is anticipated to increase as marine fish catches have already exceeded the maximum sustainable yield. In order to address this issue, aquaculture is being developed on a commercial scale. Fish farming in Malaysia is focused on providing the...
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| Format: | Thesis |
| Language: | English English |
| Published: |
2002
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| Subjects: | |
| Online Access: | http://psasir.upm.edu.my/id/eprint/9482/1/FSAS_2002_28_A.pdf |
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| Summary: | In Malaysia, the role of aquaculture in fish production is anticipated to increase as
marine fish catches have already exceeded the maximum sustainable yield. In order to
address this issue, aquaculture is being developed on a commercial scale. Fish farming
in Malaysia is focused on providing the fish grower with the best fingerlings, with
uniformity and fast growth rates. There is great necessity for genetic evaluation,
monitoring of stocks and application of appropriate breeding approaches if tilapia
production is to continue to meet market demands. With the aid of microsatellite
markers, stock integrity and genetic variability can be examined.
Three major experiments were carried out; a population genetic study on eight
populations of tilapia. quantitative genetics study on two populations of O. niloticus.
Taiwan A and B across two generations and heritability study on the Taiwan A
population.
The primary focus of the population genetic study was to determine the
relationships among eight populations which was used for breeding and to determine the
viability of these populations. Microsatellite markers were used to determine the
relationships among tilapia populations. The technique was optimized by varying
parameters including the amount of template DNA, different thermal cyclers and others.
The results showed that microsatellite markers are good markers for tilapia genetic
studies.
For the population genetic study, the mean allele number and the mean
heterozygosity level for the 40 loci were 43 and 0.5420 respectively. The FST value of
0.2401 among the populations suggested a moderate amount of genetic differentiation
among the tilapia populations studied. Low heterozygosity levels suggest low effective
population sizes, which may result in high levels ·of inbreeding. Most loci showed a
deficiency in heterozygosity, which may be a sign of inbreeding. Most sampled
populations showed significant deviations from Hardy-Weinberg equilibrium, which
could result from mutation, migration or selection. This outcome could also be due to
the small sample sizes examined and the high number of alleles present at individual
loci.
Based on 11 loci, different genetic distance measures were applied to test the
difference in the topology of the five populations examined. The topology and
correlation values varied using two models, IAM and SMM. The genetic distances used
in this study was selected to resolve relationships among the sampled populations as an |
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