Citation
Hoh, Boon Peng
(2005)
Isolation, Characterization and Genetic Linkage Mapping of Microsatellite Markers in Mystus Nemurus.
Doctoral thesis, Universiti Putra Malaysia.
Abstract
The river catfish (Mystus nemurus) is of great potential importance as an alternative fish
protein source, notably in Malaysia and Thailand. The seed supply is seasonal and
inability to reproduce in captivity is a hindrance to mass produce this species. Molecular
breeding and genetic mapping with the use of DNA based markers have paved ways in
overcoming conventional breeding to improve important economic traits.
The main objectives of this study were to isolate and develop microsatellite markers for
Mystus nemurus, and apply these markers on genetic linkage map for this species. Two
methodologies were used to isolate the microsatellite loci in M. nemurus, namely
Random Amplified Hybridizing Microsatellites (RAHMs) and 5' anchored Polymerase
Chain Reaction (5' anchored PCR). A total of 236 repeat sequences were identified. Of
these, 13 were developed fiom RAHMs and 223 were developed from 5' anchored
PCR.A total of 177 primer pairs were developed. Of these 64 have been screened for
polymorphisms on 90 unrelated fishes collected from six locations (Kedah, Selangor,
Perak, Johor, Terengganu and Sarawak), where each location consisted of 15
individuals. Forty four primer pairs were found to be polymorphic. The highest
heterozygous marker was MnBp5-1-12a (0.871 4) while the lowest heterozygosity was
observed in MnBp8-1-25a (0.0000). A dendrogram was constructed from the 44
polymorphic loci. An additional 34 polymorphic markers, previously generated, were
combined in order to construct another dendrogram, and it was found that the
dendrograrn stabilized at 50 polymorphic microsatellite loci.
Induced breeding was carried out to generate two known fish family groupings. The
first family grouping was generated from the parents chosen randomly from the
Terengganu broodstock. One hundred progeny were produced. The second family
grouping was generated from the male chosen from Terengganu population and the
female chosen from Pahang population. Fifty progenies were used for the analysis of
Mendelian segregation and linkage mapping.
A total of 70 microsatellite markers isolated for this species were screened and
evaluated for the Mendelian Inheritance ratio on the two fish families, mentioned of
which 31 showed segregation in either one of the families. These markers were
analyzed with contingency chi-square analysis. Of these, 13 pair markers were grouped
into 8 groups. Strategy "Pseudo-testcross" was applied in the linkage mapping analysis.
Analysis of linkage using LOD score was carried out and a total of 7 linkage groups were generated from the 2 fish families under the LOD of 1.2. Additional analysis of
LOD was performed on the family data of 44 dominant markers done previously. Three
linkage groups were obtained at the LOD of 1.2 and fractionated into 6 groups when the
LOD score was increased to 2.0.
This is the first map generated for M. nemurus which provides information on genetic
linkage for this species. It is a stepping-stone for carrying out more intensive genetic
mapping and QTL analysis on this species in the future. Eventually, marker assisted
selection (MAS) or isolation of economically important genes could be made possible
and these would benefit the Malaysian aquaculture industry
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Additional Metadata
Item Type: |
Thesis
(Doctoral)
|
Subject: |
Microsatellites (Genetics) |
Subject: |
Genetic markers |
Subject: |
Catfishes |
Call Number: |
FS 2006 11 |
Chairman Supervisor: |
Associate Professor Siti Shapor Siraj, PhD |
Divisions: |
Faculty of Science |
Depositing User: |
Nur Izyan Mohd Zaki
|
Date Deposited: |
12 May 2010 07:35 |
Last Modified: |
20 Oct 2023 03:40 |
URI: |
http://psasir.upm.edu.my/id/eprint/6284 |
Statistic Details: |
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