Molecular genetic technology is developing strongly and has proven effective in breeding programs for aquatic species worldwide, including carp. Implementing new carp breeding programs, combining quantitative genetics and molecular genetics, is a necessary direction for Vietnam to improve the quality of carp broodstock and promote sustainable high-tech aquaculture.
Modern breeding methods combine traditional genetic methods (based on phenotypic and pedigree information) and molecular genetic methods (information on differences in DNA sequences – molecular markers) to yield accurate results and shorten the selection process.
Molecular markers are DNA sequences that reflect genetic diversity or polymorphism created by mutations in the genome. Genome-based technologies, including molecular markers, gene analysis, quantitative trait loci (QTL) analysis, genome-wide association studies (GWAS), expression analysis, and bioinformatics analysis, are potential tools used to identify genotypic variants associated with specific phenotypic traits, thereby allowing prediction of phenotypes that positively impact production or product quality.
Globally, carp has been one of the earliest subjects for molecular marker development research. Initial studies focused on developing microsatellite markers, which are co-dominant, highly polymorphic, easy to detect, and follow Mendelian inheritance laws, making them highly suitable for population structure studies, pedigree analysis, and capable of detecting differences between closely related species. With the advancement of gene technology, single nucleotide polymorphism (SNP) markers are widely used because they account for over 90% of individual differences, serving as a new and powerful tool in molecular genetic research. These two types of molecular markers have been widely developed and applied in studies on genetic diversity, gene structure, and trait linkage mapping to support carp breeding programs.
In Vietnam, the first studies on molecular markers and their application in aquaculture breeding were conducted on pangasius. Microsatellite markers have been used to study genes linked to flesh color traits; to study the genetic diversity of pangasius broodstock populations using RAPD and AFLP markers; to assess the genetic diversity of selected pangasius populations; to apply microsatellite molecular markers in pangasius breeding pedigree research, and most recently, to assess the genetic diversity of wild pangasius using a set of microsatellite markers.
Additionally, the application of next-generation sequencing technology in decoding the entire transcriptome and developing SNP markers linked to fast-growth traits in selected pangasius was also carried out by the research group of Kim Thi Phuong Oanh et al. (2018). Studies evaluating genetic variation using microsatellite markers on 9 populations of striped tilapia, created by crossbreeding three strains: GIFT strain striped tilapia, Taiwan strain striped tilapia, and the 7th generation selected striped tilapia at Research Institute for Aquaculture I; Microsatellite markers were used to assess the genetic diversity of the initial stock for breeding programs of red tilapia and striped tilapia grown under sub-optimal temperature conditions; Genetic studies of microsatellite markers on hybrid tilapia for male monosex production. For carp, studies using molecular markers in genetic analysis have also been conducted since 2006. Thai Thanh Binh et al. studied genetic structure using mitochondrial DNA and genetic diversity using Microsatellite (2007), aiming to evaluate and select carp populations for breeding programs. The research group of Nguyen Huu Ninh et al. (2011) used seven microsatellite markers in a study to construct family pedigrees for selected carp populations across three generations: G0, G1, and G2.
However, molecular marker studies applied to carp breeding in Vietnam have not yet received sufficient attention or been effectively applied in breeding programs, unlike pangasius and tilapia. The most recent study conducted was on the identification and genetic structure using COI and Dloop genes for carp populations from different geographical regions.
PKT THAN VUONG COMPANY
SOURCE: RESEARCH INSTITUTE FOR AQUACULTURE I
