Chromosomal regions influencing egg production and egg quality traits in hens

Egg production and egg quality traits are a major issue for all the actors in the poultry industry. To date, 41 studies have detected many chromosomal regions influencing egg production and egg quality traits in hens. Thus, 442 Quantitative Trait Loci (QTL), spread over 26 chromosomes, were detected in 27 populations. Some of these regions have joint effects on several traits. Some have significant effects in various populations, highlighting their key role in establishing the performance level of hens. Several candidate genes have been revealed by these studies, such as the RARRE1 gene that affects many traits. However, the functional validation of the effects of these genes remains to be done to demonstrate their causality. In the future, the huge dataset of genotypic and phenotypic data, due to the genomic selection implementation, will allow narrowing down the location of the causal polymorphisms and, probably, to detect new regions.