Direct allele introgression into pure chicken breeds using Sire Dam Surrogate (SDS) mating

Maeve Ballantyne,Lorna Taylor,Dadakhalandar Doddamani,Mark Woodcock,Mike J Mcgrew,Tuanjun Hu,Rachel J Hawken

doi:10.1038/s41467-020-20812-x

Maeve Ballantyne, Lorna Taylor + Show 5 more

Open Access

https://doi.org/10.1038/s41467-020-20812-x

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Abstract

Poultry is the most abundant livestock species with over 60 billion chickens raised globally per year. The majority of chicken are produced from commercial flocks, however many indigenous chicken breeds play an important role in rural economies as they are well adapted to local environmental and scavenging conditions. The ability to make precise genetic changes in chicken will permit the validation of genetic variants responsible for climate adaptation and disease resilience, and the transfer of beneficial alleles between breeds. Here, we generate a novel inducibly sterile surrogate host chicken. Introducing donor genome edited primordial germ cells into the sterile male and female host embryos produces adult chicken carrying only exogenous germ cells. Subsequent direct mating of the surrogate hosts, Sire Dam Surrogate (SDS) mating, recreates the donor chicken breed carrying the edited allele in a single generation. We demonstrate the introgression and validation of two feather trait alleles, Dominant white and Frizzle into two pure chicken breeds using the SDS surrogate hosts.

Highlights

Introduction of theFrizzle (FRZ) feather trait into a traditional European breed
The inducible caspase-9 protein consists of a truncated human caspase-9 protein fused to the FK506-binding protein (FKBP) drugdependent dimerisation domain[18]
The chemical compound, AP20187 (B/B), induces the dimerisation of FKBP and subsequent activation of the adjoining caspase-9 protein leading to induced apoptotic cell death. iCaspase[9] has previously been used as a cellular suicide gene for human stem cell therapy[18,19,20] and to ablate cell lineages in transgenic animals[21,22]

Summary

Introduction

Frizzle (FRZ) feather trait into a traditional European breed. An autosomal recessive modifier gene (mf) that lessens the effects of the FRZ allele is present in many European chicken breeds, leading to a minor frizzled phenotype in young chicken and a crumpling of the barbs of the anterior flight feathers[37,38]. We again used high fidelity Cas[9], SpCas9-HF1, and a 100 bp ssODN template to introduce the FRZ deletion into the KRT75 gene of female LSX PGCs. After clonal isolation and propagation, we found that 10% of the PGCs clones were homozygous for the FRZ deletion (Fig. 5a). A homozygous KRT75-edited female clone selected for the generation of FRZ edited birds was screened for potential off-targeting mutations. No novel mutations were detected in the five off-target sites analysed (Supplementary Fig. 13)

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