Quantitative trait loci affecting eggshell traits in an F₂ population

Abstract

Good eggshell quality is important for both table egg quality and chicken reproductive performance. Weak eggshells cause economic losses in all production steps. Poor eggshell quality also poses increased risk for Salmonella infections. Eggshell quality has been a difficult trait to improve by traditional breeding, as it can be measured only for females and it is difficult and expensive to measure. Breeding for improved shell quality may therefore benefit from the use of marker-assisted selection. In an effort to find markers linked to eggshell quality, we have used an F(2) population of 668 females to map quantitative trait loci (QTL) affecting eggshell traits (eggshell deformation, breaking force, weight). By using 160 microsatellite markers on 27 chromosomes, we found 11 genome-wide and 15 suggestive QTL for shell traits measured at different times during production. Loci affecting the deformation were found on chromosomes 1, 2, 6, 10, 14 and Z. Loci affecting the breaking force were detected on chromosomes 2, 3, 10, 12 and Z. Loci affecting the shell weight were detected on chromosomes 6, 12, 24 and Z. Each QTL explains between 1.5% and 4.6% of the phenotypic variance, adding up to 10-15% of total phenotypic variance explained for the different traits. No epistatic effects were observed between loci affecting eggshell traits. Because the effects for quality are mainly additive, these results provide a basis for further characterization of the loci to identify closely linked markers to be used in marker-assisted selection.

Functional classification of 15 million SNPs detected from diverse chicken populations

“…61 The region harbouring the ADAMTS7 gene overlapped with QTLs for several traits including two for egg-shell strength and stiffness. 62 Nevertheless, since the members of this gene family are known to perform a variety of physiological roles by encoding enzymes with protease activities, the ADAMTS7 genes may have wider effects on multiple traits. 63 …”

Mapping of Main-Effect and Epistatic Quantitative Trait Loci for Internal Egg Traits in an F₂ Resource Population of Chickens

“…However, the other loci have definitive effects on internal egg traits in one or two stages only. Abasht et al (2009) andTuiskula-Haavisto et al (2010) reported QTLs influencing egg traits in different stages and on different chromosomal regions, and they discussed partial genetic independence of most traits at different ages. The present study also revealed that the same trait in the different stages is regulated by multiple loci with age-related effects and those have different effect sizes contributing to the trait.…”

Relationship between the Production Traits and three Candidate Genes in the Prolactin’s In/Del×In/Del Population of Silkie Fowl

“…NPY is an abundant and widespread neuropeptide in the nervous system of avian species (Kuenzel and McMurtry, 1988), but we did not find any reports on the relationship between eggshell strength and the NPY gene. Tuiskula-Haavisto et al (2010) have reported that quantitative trait loci (QTLs) that affect the deformation and breaking force of eggs are found on chromosome 2. However, the position of the QTLs was distinct from the position of the NPY gene on chromosome 2.…”