# Variation in the prion protein gene (PRNP) open reading frame sequence in French cervids

## TL;DR

This study examines genetic variation in the prion protein gene (PRNP) in French roe deer and red deer to understand their susceptibility to chronic wasting disease.

## Contribution

The study provides a detailed analysis of PRNP polymorphisms in French cervids, revealing species-specific genetic diversity patterns.

## Key findings

- French roe deer showed a monomorphic PRNP gene except for one heterozygous animal with a G37A mutation.
- Red deer displayed multiple non-synonymous and synonymous substitutions, including a new 24bp deletion.
- Significant regional variation in PRNP polymorphism frequencies was observed among French regions.

## Abstract

The recent emergence of chronic wasting disease (CWD) in Europe has become a new public health risk for monitoring of wild and farmed cervids. This disease, due to prions, has proliferated in North America in a contagious manner. In several mammalian species, polymorphisms in the prion protein gene (PRNP) play a crucial role in the susceptibility to prions and their spread. To obtain a reliable picture of the distribution of PRNP polymorphisms in the two most common cervid species in France, we sequenced the open reading frame (ORF) of this gene in 2114 animals, 1116 roe deer (Capreolus capreolus) and 998 red deer (Cervus elaphus). Selection criteria such as historical origin, spatial distribution and sex ratio have been integrated to establish this sample collection. Except for one heterozygous animal with a non-synonymous mutation at codon 37 (G37A), all the 1116 French roe deer were monomorphic. Red deer showed greater variation with two non-synonymous substitutions (T98A; Q226E), three synonymous substitutions (codons 21, 78 and 136) and a new 24pb deletion (Δ69-77). We found significant regional variations between French regions in the frequency of the identified substitutions. After cloning of the PRNP ORF from animals presenting multiple non-synonymous polymorphisms, we identified six haplotypes and obtained a total of twelve genotypes. As in other European countries, we highlighted the apparent homogeneity of PRNP in the French roe deer and the existence of a greater diversity in the red deer. These results were in line with European phylogeographic studies on these two species.