Association between Fbxl5 gene polymorphisms and partial economic traits in Jinghai Yellow chickens

The Fbxl5 gene is a member of the F-BOX family and plays an important role in maintaining iron homeostasis in cells. In order to reveal the genetic effects of Fbxl5 gene polymorphisms on body weight (BW) traits and reproductive performance in chickens, Fbxl5 gene polymorphisms were detected in 363 Jinghai Yellow chickens by PCR-single-strand conformation polymorphism (SSCP) and DNA sequencing methods using three primers. With primer 1, three genotypes (BB, bb, Bb) were detected in the Jinghai Yellow chicken population and two mutations (g. 14257 T  $$  C and g. 14262 T  $$  C) were revealed by gene sequencing. With primer 2, two genotypes (EE, Ee) were detected in the same population and one mutation (g. 19018 G  $$  A), and for primer 3, three genotypes (FF, ff, Ff) and one mutation (g. 19018 G  $$  A) were detected. Four single nucleotide polymorphisms (SNPs) were used to estimate the frequency distributions of the eight haplotypes with PHASE 2.1 software. CTCG was the major haplotype with a frequency of 37.93 %, while the least frequent was TCTA with a frequency of 2.98 %. The BW of haplotype combination H1H8 was higher than that of the other haplotypes and was a dominant combination. In terms of reproductive performance, the age at the first egg of the haplotype combination H9H1 was later than in the other haplotypes, but the mean egg weight at 300 days was relatively optimal. The H1H2 haplotype produced the highest mean egg weight in 300 days, although the total number of eggs in 300 days was smaller in the H2H4 haplotype with the highest at first egg. Therefore, we can consider using the haplotype combination H1H2 for selection. The findings of this study expand the theoretical basis of the use of the Fbxl5 gene in the molecular breeding of poultry.