# Genetic Variability of Loci Affecting Meat Quality and Production in Nero Siciliano Pig Breed

## TL;DR

This study examines the genetic diversity of genes affecting meat quality and growth in the endangered Nero Siciliano pig breed to support its conservation and meat production.

## Contribution

The study identifies high frequencies of beneficial and harmful genetic variants in Nero Siciliano pigs, emphasizing the need for genetic monitoring.

## Key findings

- High frequencies of alleles linked to growth and fat deposition were found in the Nero Siciliano breed.
- The RYR1 g.1843T allele, associated with meat defects, was detected in seven pigs, highlighting the need for its eradication.
- Genetic deviations from Hardy–Weinberg equilibrium and differences in allele distribution between boars and sows were observed.

## Abstract

Nero Siciliano is a native pig breed mainly reared in an open-air system in the mountainous area of north-eastern Sicily. Despite its economic importance and the high-quality meat products, the breed is currently endangered. As part of a broader project to characterize and support the conservation of this breed, the genetic variability of four candidate genes involved in back fat deposition and growth rate was evaluated to provide useful information for the promotion of Nero Siciliano meat products. By analyzing a representative sample of pigs reared in the original breeding area, high frequencies of gene polymorphisms linked to different growth rates and fat deposition were detected. A deleterious RYR1 g.1843T allele to cause malignant hyperthermia and pale, soft, exudative meat was detected in seven heterozygous pigs. These results highlight the importance of regular genetic monitoring to promote beneficial traits and eradicate harmful variants, preserving local producers and this endangered breed.

Nero Siciliano (NS) is an autochthonous pig breed reared in northeastern Sicily; despite its high-quality meat products, NS is currently endangered. This study aimed to evaluate the genetic variability at nine loci within candidate genes for meat traits—Melanocortin 4 Receptor (MC4R), Ryanodine Receptor 1 (RYR1), Class 3 Phosphoinositide 3-Kinase (PIK3C3) and Leptin (LEP)—to provide useful information for preservation and exploitation of the NS pig breed. Distribution of the genetic variants was assessed in a representative sample of 87 pigs (18 boars and 69 sows) collected in nine farms located in the original breeding area. Genotypes have been determined using PCR-RFLP and Sanger sequencing. Alleles linked to different growth rates and back fat deposition showed high frequencies (MC4R c.175C—0.93; LEP g.3469T—0.91) in the whole sample. Deviations from Hardy–Weinberg equilibrium and different allele distribution in boars and sows were observed. The RYR1 g.1843T allele, associated with Malignant Hyperthermia and Pale Soft Exudative meat defect, was reported in seven heterozygote pigs (q = 0.04) with one farm exhibiting a frequency of 0.29. Our results suggest the need for continuous monitoring of the genetic variants in NS both to maintain high meat quality and eradicate the RYR1 g.1843T allele.