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

Abstract

Quantitative trait loci (QTLs) analyses for internal egg quality of chickens were performed with 143 microsatellite markers on 27 linkage groups in 371 F 2 hens obtained from an intercross between Japanese Large Game (Oh-Shamo) and White Leghorn breeds. Internal egg traits, such as weight and size of the albumen, weight and size of the yolk, and yolk colors, were measured in three different egg laying stages (early, middle, and late stages). We detected 11 significant and four suggestive QTLs with main effects on 27 internal egg traits in the three stages. Albumen weight and size QTLs were identified on chromosomes 1, 2, 4, 5, 6, 8, 9, 27, and Z. Yolk weight and size QTLs were discovered on chromosomes 4, 7, 8, 15, and Z, whereas yolk color QTLs were detected on chromosomes 1, 3, 4, 8, 9, and 27. Moreover, we revealed four significant and two suggestive QTLs with epistatic interaction effects on three internal egg traits in the late stage. This is the first report of epistatic QTLs for internal egg traits in chickens. The four significant loci were on chromosomes 1, 2, 8, and 17 and affected yolk size and yolk color, whereas the two suggestive loci were located on chromosomes 2 and 10 and affected albumen height. Among these epistatic QTLs, the two QTLs detected on chromosomes 1 and 8 were found at the regions of main-effect QTLs. The present main and epistatic QTLs accounted for 3.61-18.46% of the phenotypic variances. The chromosomes 1 and 8 QTLs with main effects on internal egg traits exerted their effects throughout all three stages, whereas the other QTLs with main-or epistatic-effects were detected in one or two stages. These results demonstrated that age-related changes of QTLs will make the genetic features of quantitative traits more complex.

Characteristics of Egg-related Traits in the Onagadori (Japanese Extremely Long Tail) Breed of Chickens

“…The differences observed in PC2, PC3, and PC4 indicate that Onagadori eggs have apparently different features from those of the White Leghorn in eggshell-related traits and the volume of the whole egg and albumen. Thus, the Onagadori will be a useful material for analyzing genetic loci affecting the variation of these egg-related traits as in the case of the Oh-Shamo (Tsudzuki et al, 2007;Goto et al, 2011Goto et al, , 2014aGoto et al, , 2014bYoshida et al, 2013). The plural traits in the same principal component might be controlled partially by the same genetic basis.…”

“…AH and YH were measured using an egg quality meter (Fujihira Industry). The ABS digital caliper (Nakamura Mfg., Nagano, Japan) was used for LTA, STA, YL, and YS measurement as described in Goto et al (2014aGoto et al ( , 2014b. We found only one soft shell egg laid by Onagadori and excluded it from the analysis.…”

“…In fact, microsatellite analyses revealed that they mostly show a large genetic distance when compared with foreign breeds (Osman et al, 2006). In recent years, many quantitative trait loci (QTLs) for growth-, meat-, and egg-related traits were identified using some native Japanese chicken breeds Fujinaka, 2001a, 2001b;Tsudzuki et al, 2007;Uemoto et al, 2009Uemoto et al, , 2011Goto et al, 2011Goto et al, , 2014aGoto et al, , 2014bRikimaru et al, 2011;Yoshida et al, 2013), which suggests that native Japanese chickens are valuable genetic resources for understanding genetic architecture underlying the phenotypic traits.…”

Genetic and Productive Studies on Egyptian Local and Exotic Laying Hen Breeds

“…Genomic DNA was extracted from blood using AXYGEN kit (Axygen Scientific, inc. USA). Ten microsatellite markers (HUJ7, MCW222, ADL268, MCW154, LEI0234, MCW216, ADL278, MCW295, LEI094 and LEI166) were selected based on the chicken genome database (Pandey et al, 2005;Honkatukia et al, 2013;Wei et al, 2013;Goto et al, 2014). Four markers were in linkage with production traits; HUJ7 and MCW154 with egg production while LEI0166 and LEI0094 were associated with growth traits.…”

Genetic Mapping of Quantitative Trait Loci for Egg Production and Egg Quality Traits in Chickens: a Review

“…In Hiroshima University, Japan, Tsudzuki (the last author of this article) and colleagues have constructed a large experimental F 2 resource population in chickens for QTL analysis. The resource population was produced by crossing males of the Japanese Large Game (Oh-Shamo) breed, known for cockfighting, with females of the White Leghorn breeds, and consists of three sub-populations: a population for growth- and meat-related traits ( Tsudzuki et al , 2007 ; Yoshida et al , 2013 ), a population for growth- and egg-related traits ( Goto et al , 2011 , 2014a , b ), and a population for growth-related traits. Of note, the population for growth and egg-related traits has 421 F 2 females and well-documented phenotypes that describe a wide range of egg production stages.…”