Genetic mapping of quantitative trait loci affecting body weight, egg character and egg production in F2 intercross chickens

Abstract

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 for egg production) of chickens were identified. An F2 population comprising 265 female chickens obtained by crossing White Leghorn and Rhode Island Red breeds and genotyped for 123 microsatellite markers was used for detecting QTL. Ninety-six markers were mapped on 25 autosomal linkage groups, and 13 markers were mapped on one Z chromosomal linkage group. Eight previous unmapped markers were assigned to their respective chromosomes in this study. Significant QTL were detected for BW on chromosomes 4 and 27, egg weight on chromosome 4, the short length of egg on chromosome 4, and redness of egg shell colour (using the L*a*b* colour system) on chromosome 11. A significant QTL on the Z chromosome was linked with age at first egg. Significant QTL could account for 6-19% of the phenotypic variance in the F2 population.

Tissue expression, association analysis between three novel SNPs of the RXRα gene and growth traits in Chinese indigenous cattle

“…The swine RXR gene located on chromosome 1 about from 288.83 to 288.86 Mb, in this region some QTLs associated with production and meat quality traits was mapped, such as abdominal fat weight [29], backfat [30,31], body weight [32] and average daily gain [32,33]. The chicken RXR gene was located on chromosome 17 about from 7.27 to 7.35 Mb, and we found some QTLs associated with meat quality traits located in this region, such as abdominal fat percentage and drumstick weight [34], bone mineral content and tibia length [35], abdominal fat weight [36], body weight [37]. Thus, the bovine RXR gene, possiblely the same as the swine and chicken RXR gene, may be associated with production traits and be used as a candidate gene for production traits in cattle.…”

Identification of quantitative trait loci associated with bone traits and body weight in an F2 resource population of chickens

“…A number of QTL mapping studies have been performed on crosses between genetically and phenotypically divergent lines of chickens. These studies have focused on identifying QTL responsible for body weight [39,46,47,51,52,55], feed-efficiency [57], growth [7,20,27,55,57,62], carcass characteristics [12,23,24,56], and egg traits [27,39,44,54,59]. Other researchers have investigated specific candidate genes potentially associated with variation in traits relating to bone integrity [31,61].…”

W chromosome expression responds to female-specific selection

“…traits (22,31,32), or for marker-assisted selection for industrial egg production. However, CNV does not explain the majority of variation in expression.…”