Bangladeshi scientists have successfully decoded the genome sequence of hilsa, opening up a new era in sustainable production and conservation of national fish, of which Bangladesh is the world’s largest producer.
Professor Dr. Md. Samsul Alam of the Department of Fisheries Biology and Genetics at Bangladesh Agricultural University (BAU) in Mymensingh led the research programme. The research team also comprised of Dr Md. Bazlur Rahman Mollah of the Department of Poultry Science, Professor Dr. Md. Shahidul Islam of the Department of Biotechnology and Professor Dr. Mohd Golam Quader Khan of the Department of Fisheries Biology and Genetics at BAU.The research team collected live and mature hilsa from the Meghna River and the Bay of Bengal from 4 to 20 May in 2016 and extracted high-quality genomic DNA at the Fish Genetics and Biotechnology Laboratory and Poultry Biotechnology Genomics Laboratory at BAU, said Dr Md. Samsul Alam.
“We obtained the raw sequence data separately from the hilsa samples collected from the Meghna River and Bay of Bengal using the next generation DNA Sequencer IlluminaHiSeqX at GENEWIZ Genome Sequencing Center in the USA,” he said.
The researchers then completed the de novo assembling of the genome sequence using different bioinformatics programs run by powerful computers at the University Grants Commission (UGC).
The assembled hilsa genome contained 7.68 million nucleotide (basic structural unit and building block for DNA) which is approximately ¼ of the human genome, according to the research team.
They submitted the hilsa whole genome sequence to the international genome database (National Center for Biotechnology Information, USA) and presented the research findings on Hilsa genome sequencing at two different International conferences (26th Plant & Animal Genome Conference, January 13-17, 2018, San Diego, California, USA; 3rd GNOBB International Conference, September, 29-30, 2017, Senate Bhaban, Dhaka University).
Hilsa (Tenualosailisha) is the national fish of Bangladesh. The contribution of Hilsa as a single species is the highest, approximately 12 per cent of total fish production of the country. On the other hand, about 60 per cent of the world Hilsa is produced in Bangladesh.The livelihood of around 4 lakh people of the country directly depends on Hilsa fishing.
Hilsa is a migratory fish dwelling in the sea around the year but migrates to upstream rivers for spawning and returns back to the sea after spawning. The hatched fry are nourished and nurtured to juvenile (jatka) in the river and then moved to the sea.
It is, however, very important that the conservation management activities be matched with the biological features of hilsa for their effectiveness in increased and sustainable production.
The whole genome sequencing could meticulously help identify the hilsa stocks, that indicates the hilsa a population in a particular geographic region.
In Bangladesh, hilsa migrates to different rivers for spawning, e.g., Meghna, Padma, Paira, Andharmanik etc. The question is if the hilsa migrating to different rivers belong the same stock or different stocks. Genome sequencing could provide answers to these questions.
Genetic relationship among the juveniles (jatka) and adult hilsa, location for the establishment of hilsa sanctuary, genetical differences between Bangladeshi hilsa and hilsa from other countries could be identified with the genome decoded.
The genomic technology will also help develop management strategies for sustainable exploitation of hilsa as well as for their conservation.