Genetic diversity of Hilsa and Chapila in Bangladesh using DNA barcodingand RAPD techniques

Abstract

Fisheries is one of the most important sectors in the socio-economic context of our country. Fishes are the major source of animal protein and it contributes about 60% of the animal protein intake. Tenualosa ilisha is the national fish of Bangladesh. “Jatka” are captured in a large quantity by artisanal fishers and sold on local markets as “chapila”. The main purposes of the study were morphological identification and genetic characterization of “chapila” and different species of “hilsa”. Morphometric study and DNA barcoding were used for species identification. Species identification based on the DNA sequence of a fragment of the cytochrome c oxidase subunit I gene in the mitochondrial genome, DNA barcoding, is widely applied to assist in sustainable exploitation of fish resources. RAPD (Randomly Amplified Polymorphic DNA) analyses were used to find out the genetic distances by ten arbitrary oligonucleotide RAPD primers. Four different species of chapila (Gudusia chapra), hilsa (Tenualosa ilisha), toli shad (Tenualosa toli) and big eye ilish (Ilisha megaloptera) were identified by morphometric study. But DNA barcoding shows there were two different species of Indian oil sardine (Sardinella longiceps) and kelee shad (Hilsa kelee). A total of 134 bands were produced in RAPD analysis among four species where 23 bands were polymorphic indicating 18.48% polymorphisms. The molecular size of the amplified DNA fragments ranged between 200 to 1480bp and 83unique RAPD bands were observed among four populations.The values of pair-wise genetic distances ranged between 0.5077 and 0.9933with some degrees of genetic variation among the populations.The highest genetic distance (0.9933) was found between Gudusia chapra and Sardinella longiceps. While the lowest genetic distance (0.5077) was found between Sardinella longiceps and Hilsa kelee.The UPGMA dendrogramsegregated the four populations in three major clusters viz. C1, C2 and C3. Clusters C1 and C2 comprised Sardinella longiceps and Hilsa kelee. On the other hand, Gudusia chapra created the new distant cluster C3. Results show that DNA barcoding is a reliable tool for species identification. Genetic diversity information may be used for improved breeding programme and conservation of those four populations.