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International Journal of Marine Science 2015, Vol.5, No.5: 1-8
http://ijms.biopublisher.ca
5
Table 3 Standardized Canonical Discriminant Function Coefficients
that derived from Discriminant Function analysis (DFA) for two
Penaeus semisulcatus
populations
Land marks
Function 01
4~5
0.075
5~6
-
0.265
6~7
-
0.158
7~8
0.119
8~9
-
0.226
10~11
-
0.008
12~13
0.022
14~15
-
0.085
16~17
-
0.025
2~18
0.108
3~17
0.664
6~14
-
0.224
3~16
-
0.426
4~15
-
0.816
5~14
3.177
6~13
-
0.362
7~12
-
0.333
3~18
0.168
6~15
-
0.419
8~13
0.190
9~12
-
0.741
This study analyzed gene regions from both mtDNA
and nucDNA gene regions including coding,
non-coding and hyper variable mitochondrial control
gene region. Results of six gene regions indicated low
genetic variation between two wild populations. High
genetic variability was evident for mtDNA control
gene region which produced seven haplotypes. This
pattern is concordant with the past studies conducted
for
P. monodon
populations (Chu et al., 2003; Kumar
et al., 2007; You et al., 2007; Khedkar et al., 2013).
The seven haplotypes separated into two distinct
groups in the phylogenetic tree (Figure 4). It is evident
that the availability of low genetic variation between
northern and southern
P. semisulcatus
wild
populations due to low nucleotide divergence levels
among common haplotypes between two populations.
The phylogenetic tree derived for haplotypes
produced from COI gene region clearly separated the
common haplotype (KM 528139) from other two
(Figure 5). The nucleotide divergence levels derived
for mtDNA control and COI gene regions were within
the range when compared with the published data for
other
Penaeus
species (Lavery et al., 2004).
Figure 4 Neighbor Joining (NJ) tree derived from seven
haplotypes of control gene region.
Fenneropenaeus
sp. used as
an out group, Bootstrap values less than 50 are not indicated
indicated
Figure 5 Neighbor Joining (NJ) tree derived from three
haplotypes of COI gene region.
Fenneropenaeus
sp. used as an
out group
According to Silva et al (2012), the Jaffna lagoon of
the extreme northern and Walawe River estuary of the
extreme southern regions of the Sri Lanka comprise of
different environmental conditions and have been
classified under two different categories. Results
indicated the availability of phenotypic plasticity
which means, possibility of produce different
phenotypes for organisms with the same genotype
under different environmental conditions (Thibert-plante
and Hendry, 2011). This phenomenon is known as a
common response to environmental gradients (Via et
al., 1995; Agrawal, 2001) and common among marine
organisms (Munday, 2013). It has been suggested that
marine crustaceans those with high dispersal potential
(i.e., long-lived planktonic larvae) often display
phenotypic plasticity than those with low dispersal
ability (Hollander, 2008). Phenotypic plasticity is also
arising as heterochronic phenotypic variation,
which has been reported from crustaceans especially
those species undergo abbreviated larval development
(Kavanagh et al
.
, 2006; Ozawa and Ishii, 2008). It has
been further suggested that the phenotypic plasticity
could correspond to phenotype fixation, a kind of