Publication Date:
2021-07-16
Description:
Information on the genetic structure of fish populations is useful for identification of stocks, management for sustainable exploitation and preservation of genetic diversity. The most important objective in population genetics is discrimination between populations within their distribution areas. The invention of polymerase chain reaction has created new possibilities for exploration of these differences in fish populations. One of these PCRbased methods is Random Amplified Polymorphic DNA (RAPD) which uses short oligonucleotide primers of arbitrary sequences to amplify discrete regions of the genome. The most important features of this method are: obtaining a large number of polymorphic DNA bands using tiny amounts of DNA without necessity of cloning or previous knowledge of DNA sequence. Ilisha shad (Tenualosa ilisha) which is locally known as Soboor is an anadromous fish living in sea shores, estuaries and downstream of rivers and migrate to upstream for spawning. The aim of this research was to study genetic structure of soboor in Khuzestan waters, including Karoon, Arvadrood and Bahmashir rivers, Persian Gulf (Sea) as well as Iraqi samples (caught from Shat-Al-Arab river), by using RAPD technique. For this purpose, fifteen random decamer primers were initially applied on DNA samples of 4 individuals from each region. After optimizing PCR condition, nine primers with best results were selected from which 58 polymorphic loci were obtained on 60 specimens (12 specimens from each geographical region). RAPD data were obtained by scoring 1 and 0 for presence or absence of polymorphic bands, respectively. RAPDPLOT, RAPDDIST and POPGENE computer Software were used to analyze the RAPD data. Canonical discriminant analysis was deployed for statistical analysis of the data. Maximum and minimum genetic distances were found between samples from Iraq and Sea (0.2870) and Arvandrood and Bahmanshir (0.1042), respectively. The UPGMA dendrogram showed that the samples from Karoon and Sea form a clade whereas samples from Iraq, Arvandrood and Bahmanshir rivers form another clade suggesting the hypothesis that there are two Iranian and Iraqi populations of this species and these fish select their own specific river for spawning. According to this hypothesis the specimens from Sea would destine Karoon as their spawning river. On the other hand, two other separate groups could be corresponded to Tigris and Euphrate rivers in Iraq. Moreover, canonical discriminant analysis indicates that samples from four geographical regions are statistically different from each other and high correlation among data was found within each region (P〈0.01) suggesting that Tenualosa ilisha is a schooling species. According to the above two hypotheses and considering the distribution of specimens in phylogenetic tree it can be concluded that Bahmanshir river is a specific pathway for those fish heading Karoon river for spawning whereas Shat-Al-Arab population uses both Bahmanshir and Arvandrood rivers to reach Shat-Al-Arab. To verify these three hypotheses further studies are needed.
Keywords:
Biology
;
Fisheries
;
Iran
;
Persian Gulf
;
Khouzestan Province
;
Karoon River
;
Bahmanshir River
;
Arvandrood River
;
Population
;
Genetic
;
Tenualosa ilisha
;
Population
;
Polymerase Chain Reaction
;
DNA
;
RAPD
;
PCR
;
Spawning
Repository Name:
AquaDocs
Type:
monograph
Format:
application/pdf
Format:
application/pdf
Format:
87
