Production of light-coloured, low heat-absorbing Holstein Friesian cattle by precise embryo-mediated genome editing

Context Genome editing enables the introduction of beneficial sequence variants into genomes animals with high genetic merit in a single generation. This can be achieved by introducing primary cells followed producing live animal from these somatic cell nuclear transfer cloning. The latter step is associated low efficiencies and developmental problems due to incorrect reprogramming donor cells, causing welfare concerns. Direct fertilised one-cell embryos could circumvent this issue might better integrate improvement strategies implemented industry.Methods In vitro zygotes were injected TALEN editors repair template introduce known coat colour dilution mutation PMEL gene. Embryo biopsies screened polymerase chain reaction sequencing for intended biallelic edits before transferring verified recipients development term. Calves genotyped their coats scanned visible hyperspectral cameras assess thermal energy absorption.Key results Multiple non-mosaic calves precision edited genotypes produced, including parents. Compared controls, showed strong which was lower absorbance.Conclusions Although biopsy screening not absolutely accurate, non-mosaic, precisely readily produced embryo-mediated editing. lighter colouring caused radiative heat gain help reduce stress.Implications study validates putative causative rapidly adapt grazing cattle changing environmental conditions.