Researchers in Argentina have successfully created horse embryos after editing a gene.
Their work, involving CRISPR/Cas9 technology and somatic cell nuclear transfer, was reported last week in the journal Scientific Reports.
“To our knowledge, edited horse embryos had not been reported until now,” Lucia Natalia Moro, Diego Luis Viale and their colleagues wrote.
The study team said the application of new technologies for gene editing in horses may allow the generation of animals with improved sporting performance. The technique could also be used to correct genetic defects that cause equine diseases.
In their laboratory work, they set out to knock out the myostatin gene, a negative regulator of muscle mass development.
Research by others has shown that different versions of the myostatin gene, a pronounced inhibitor of skeletal muscle growth, is a major factor in the gene-based race-distance aptitude of racehorses.
The study team reported they successfully achieved their goal, achieving efficiency of up to 96.2% in their gene editing.
Three clonal cell lines were chosen for embryo generation by somatic cell nuclear transfer, which gave rise to edited blastocysts in each case. A blastocyst is a hollow ball comprising a handful of cells, which would then implant into the wall of the uterus, after which an amniotic sac would begin to form.
“CRISPR/Cas9 proved an efficient method to edit the horse genome in a dose-dependent manner with high specificity,” the study team reported.
The technique could ultimately be used to generate horses with improved sporting ability through a precision breeding program, they said.
However, they stressed there was still work be done before this could become a reality.
“Until now, no reliable protocols have been made available for in vitro fertilization (IVF) in horses, and an efficient method to edit embryos by ICSI has not been yet developed,” they noted.
ICSI (intracytoplasmic sperm injection) is a form of IVF. Instead of the sperm and eggs being mixed in a test tube, a single sperm is injected into each egg.
The researchers said their long-term goal was to identify alleles that confer a natural sporting advantage in some horses and incorporate them in others to endow them with the same desired characteristics.
They considered the technique to be a precision breeding strategy which had the potential to deliver desired results in only one generation.
The full study team comprised Lucia Natalia Moro, Diego Luis Viale, Juan Ignacio Bastón, Victoria Arnold, Mariana Suvá, Elisabet Wiedenmann, Martín Olguín, Santiago Miriuka and Gabriel Vichera.
Moro, L.N., Viale, D.L., Bastón, J.I. et al. Generation of myostatin edited horse embryos using CRISPR/Cas9 technology and somatic cell nuclear transfer. Sci Rep 10, 15587 (2020). https://doi.org/10.1038/s41598-020-72040-4