Association of novel polymorphisms of forkhead box L2 and growth differentiation factor-9 genes with egg production traits in local Chinese Dagu hens

Abstract

Transcription factor forkhead box L2 (FOXL2) and growth differentiation factor-9 (GDF9) genes have critical roles in the regulation of hen ovarian development. In the present study, these genes were explored as possible molecular markers associated with BW, hen-housed egg production, and egg weight in Chinese Dagu hens. Samples were analyzed using the PCR-single strand conformation polymorphism (PCR-SSCP) technique followed by sequencing analysis, and two novel single nucleotide polymorphisms (SNPs) were identified within these candidate genes. Among them, an A/G transition at base position 238 in the coding region of the FOXL2 gene and a G/T transversion at base position 1609 in exon 2 of the GDF9 gene were found to be polymorphic and named SNPs A238G and G1609T, respectively. The SNP A238G (FOXL2) leads to a nonsynonymous substitution (isoleucine77-to-valine), and when the 360 Dagu hen samples were divided into genotypes AA and AB, allele A was found to be present at a higher frequency. Furthermore, the AA genotype correlated with significantly higher hen-housed egg production at 30, 43, 57, and 66 wk of age and with a higher egg weight at 43 wk (P<0.05). For the SNP G1609T (GDF9), the hens were typed into TT and TC genotypes, with the T allele shown to be dominant. The TC genotype was also markedly correlated with higher hen-housed egg production and a higher egg weight (P<0.05). Moreover, four haplotypes were reconstructed based on these two SNPs, with the AATC haplotype found to be correlated with the highest hen-housed egg production at 30 to 66 wk of age and with higher egg weights at 43 wk (P<0.05). Collectively, the two SNPs identified in this study might be used as possible genetic molecular markers to aid in the improvement of egg production traits in chicken breeding.

New polymorphisms of PAPPA and PAPPA2 genes and their associations with egg production traits in Chinese Dagu chickens

“…In all of the examined birds, no more than two allelic sequences were observed. To explore more effective ways of breeding, many SNP detection methods were established and widely used in this field, such as the method of PCP-SSCP analysis, this genotyping method has been extensively applied in animal breeding (Zhang et al, 2012;Qin et al, 2015).…”

“…As previously reported by our group (Qin et al, 2015;Tyasi et al, 2017), the eggs for hatching were randomly selected from the Dagu chickens, of which 360 hens were hatched and raised in layered batteries under the same rearing conditions. These hens were free access to water and feed according to the nutrient requirements of local Chinese Dagu hens (NY/ T 33-2004, China).…”

“…To determine for PAPPA and PAPPA2 gene polymorphism, the PCR products were further analyzed by using the single-strand conformation polymorphism (SSCP) assay as previously described (Qin et al, 2015). Briefly, Each 10 ìl PCR product was mixed with 6 l of loading dye (0.025% bromophenol blue, 0.025% xylene cyanol, 98% deionized formamide, 2% glycerin and 10 mM EDTA).…”

Assessment of relationship between body weight and body measurementtraits of indigenous Chinese Dagu chickens using path analysis

“…Dagu chicken can survive in cold weather conditions, and yellow reddish in color (Qu et al, 2006). This chicken is a dual purpose breed which produces both meat and egg production (Qin et al, 2015). However, there is virtually no documented evidence of the relationships between their body weight and body measurements using a classical statistical tool such a path analysis.…”

Novel Polymorphisms of Adrenergic, Alpha-1B-, Receptor and Peroxisome Proliferator-activated Receptor Gamma, Coactivator 1 Beta Genes and Their Association with Egg Production Traits in Local Chinese Dagu Hens

“…It includes egg production, egg weight (EW), sexual maturity and the number of recruited dominant follicles that are regulated by various endocrine, paracrine and autocrine factors (Su et al, 1996; Qin et al, 2015a). Many of the modern chicken breeds have been generated by conventional breeding methods (such as self-selection and family selection); with enhanced egg production traits a key focus (Qin et al, 2015b). However, egg productivity is inherited as a polygenic trait, with low to moderate heritability, making the level of genetic improvements difficult to estimate (Luo et al, 2007; Biscarini et al, 2010; Venturini et al, 2013).…”