Life history traits such as fecundity are important to evolution because they make up components of lifetime fitness. Due to their polygenic architectures, such traits are difficult to investigate with genetic mapping. Therefore, little is known about their molecular basis. One possible way toward finding the underlying genes is to map intermediary molecular phenotypes, such as gene expression ...

The aim of the research was to investigate the effects of divergent selection on some production and clutch traits in Japanese quail (Coturnix coturnix japonica). Over 5 generations divergently selected two Japanese quail lines (HBW: High Body Weight and LBW: Low Body Weight) and control line (C) that derivate from a base random bred population were used in this study. Weight of first egg, age ...

A total number of 225 Fayoumi hens 34 weeks old , were used in this experiment to study the effect of supplementing layer diet with 0.2% casein (c) with or without 0.015% iodine as 0.02% potassium iodide (KI) in drinking water on the performance and egg quality. The experiment continued for 90 days. Birds were randomly divided into three groups , each group contained 3 replicates of 25 each . B...

The aim of this study is study the inheritance of economic traits in an Iranian Native chickens population by estimating genetic parameters (heritability, genetic, phenotypic and environment correlations) under short-term selection in breeding programs. Identification of genes determining the expression of economically important traits of plants and animals is a main research focus in agricultu...

Hatchability is a complex age dependent trait. It comprises of several sub-traits which are susceptible to genetic and environmental factors arising from various sources. This review examines the genetic basis of egg production, fertility and egg quality traits and how these relate with hatchability. We suggest that both sire and dam genetic components are important in overall hatchability most...

CTSD (Cathepsin D) is a key enzyme in yolk formation, and it primarily affects egg yolk weight and egg weight. However, recent research has mostly focused on the genomic structure of the CTSD gene and the enzyme's role in pathology, and less is known about the enzyme's functions in chickens. In this paper, the correlations between CTSD polymorphisms and egg quality traits were analyzed in local...

Availability of the complete genome sequence as well as high-density SNP genotyping platforms allows genome-wide association studies (GWAS) in chickens. A high-density SNP array containing 57,636 markers was employed herein to identify associated variants underlying egg production and quality traits within two lines of chickens, i.e., White Leghorn and brown-egg dwarf layers. For each individua...

Phenotypic measurements of chicken egg character and production traits are restricted to mature females only. Marker assisted selection of immature chickens using quantitative trait loci (QTL) has the potential to accelerate the genetic improvement of these traits in the chicken population. The QTL for 12 traits (i.e. body weight (BW), six for egg character, three for egg shell colour and two f...