Page 6 - IJA 1012-Vol.3 No.24

International Journal of Aquaculture, 2013, Vol.3, No.24, 138- 146
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139
introduction of Cyprinus carpio (Yousuf, 1996). A
voluminous literature reveals that no molecular and
genetic efforts were carried out for understanding
genetic relations of these species found in Kashmir.
Earlier studies remained restricted to morpho-taxonomical
studies that are obviously not ultimate tool for
characterization of any species. The information on
the genetic structure of fish species is useful for
optimizing identification of stocks, stock enhancement,
breeding programs, management for sustainable yield
and preservation of genetic diversity (Dinesh et al.,
1993; Garcia and Benzie 1995). The use of DNA
markers can contribute significantly to the development
and implementation of genetic improvement programs.
Genetic improvement programs in terrestrial species
benefit greatly from knowledge of pedigree and
individual performance. Properly designed breeding
programs can make appropriate use of additive and
non-additive genetic variation for traits of economic
importance and minimize the negative effects of
inbreeding.
The present study was undertaken to study genetic
diversity in common carp and crucian carp species
with following objectives: i) study polymorphism
using randomly amplified polymorphic DNA (RAPD),
ii) study genetic variability of the species by
restriction fragment length polymorphism (PCR-RFLP)
of cytochrome b gene, and ii) Compare the efficacy of
both the methods in determining genetic variability.
1 Results
A total of 75 specimens (25 from C.c. communis , 25
from C.c. specularis and 25 from Carassius carassius)
were analyzed. Among the 12 random primers used for
the initial screening, only eight yielded optimum
RAPD profiles with all the species under study (Table
1). A total of 3371 polymorphic markers were
generated using these primers as shown in. The number
of bands ranged from 4-12 per species and the
amplified products varied in size between 100-1400bp.
The average number of bands per primer ranged
between 182 (S-131) and 497 (S-159) with a mean of
421.3. Primer S-159 produced the highest number of
fragments among the primers used with an average of
12 fragments, and primer S-131 produced the lowest
number of fragments with an average of 5 bands. The
total number of RAPD bands produced was 3371 bands,
of which 3008 bands were polymorphic in entire
population. The proportion of polymorphic markers
across the primers ranged between 79.75% and 97.96%
with an average of 89.23%.
Table 1 Comparison of genetic diversity and dissimilarity coefficients among 75 specimens of two Cyprinidae species.
Primer Sequence G+C content Total no.
of bands
Polymorphic
bands
Percentage
Polymorphism
Molecular weight
range (Kb)
Shannons
index (H’)
S-71 5'AAAGCTGCGG3' 60 458.0 417 91.04 125-1381 1.08
S-111 5'AATCGGGCTG3' 60 473.0 377 79.70 124-1286 3.35
S-131 5'GGTCCCTGAC3' 70 182.0 173 95.05 100-1109 0.91
S-145 5'GACGGATCAG3' 60 472.0 425 90.04 192-1256 1.05
S-159 5'ACGGCGTATG3' 60 497.0 453 91.14 173-1430 1.07
S-161 5'TGCCGAGCTG3' 70 442.0 433 97.96 178-1358 1.08
S-177 5'CAGGCCCTTC3' 70 444.0 381 85.81 188-1357 1.27
S-187 5'AGTCAGCCAC3' 60 403.0 349 86.60 257-1160 1.07
Total score 3371.0 3008 -
Mean per primer 421.3 376 89.23 1.36
RAPD data from the 8 primers were used for cluster
analysis. The primers with G+C content above 60%
resulted in better polymorphism. The average
proportion of polymorphic markers across the primers
was 89.23%, ranging between 79.7 % (S-111) to
97.96% (S-161). The large number of exclusive
markers account for a substantial portion of the genetic
diversity as illustrated by the mean Shannon index per
primer 1.36 with values ranging from 0.91 (S-131) to
3.35 (S-111) shown in (Table 1 and Figure 1 ).
For further analysis, one way ANOVA was performed
for all the species and the result revealed the
non-significant difference i.e. P>0.05 for both
polymorphic and non-polymorphic banding pattern. A
positive correlation (r =0.369) was obtained between