scholarly journals Overlap of quantitative trait loci for early growth rate, and for body weight and age at onset of sexual maturity in chickens

Reproduction ◽  
2011 ◽  
Vol 141 (3) ◽  
pp. 381-389 ◽  
Author(s):  
B K Podisi ◽  
S A Knott ◽  
I C Dunn ◽  
A S Law ◽  
D W Burt ◽  
...  

Critical age, weight and body composition have been suggested as necessary correlates of sexual maturity. A genome scan to identify quantitative trait loci (QTL) for age and body weight at first egg (AFE and WFE) was conducted on 912 birds from an F2broiler–layer cross using 106 microsatellite markers. Without a covariate, QTL for body WFE were detected on chromosomes 2, 4, 8, 27 and Z and a single QTL for AFE was detected on chromosome 2. With AFE as a covariate, additional QTL for body WFE were found on chromosomes 1 and 13, with abdominal fat pad as covariate a QTL for body WFE was found on chromosome 1. With body WFE as covariate, additional QTL for AFE were found on chromosomes 1, 3, 4, 13 and 27. The QTL generally acted additively and there was no evidence for epistasis. Consistent with the original line differences, broiler alleles had positive effects on body WFE and negative effects on AFE, whereas the phenotypic correlation between the two traits was positive. The mapped QTL for body WFE cumulatively accounted for almost half the body weight difference between the chicken lines at puberty. Overlapping QTL for body WFE and body weight to 9 weeks of age indicate that most QTL affecting growth rate also affect body WFE. The co-localisation of QTL for body weight, growth and sexual maturity suggests that body weight and growth rate are closely related to the attainment of sexual maturity and that the genetic determination of growth rate has correlated effects on puberty.

2009 ◽  
Vol 41 (1) ◽  
Author(s):  
Herman W Raadsma ◽  
Peter C Thomson ◽  
Kyall R Zenger ◽  
Colin Cavanagh ◽  
Mary K Lam ◽  
...  

2014 ◽  
Author(s):  
Larry Leamy ◽  
Kari Elo ◽  
Merlyn K Nielsen ◽  
Stephanie Thorn ◽  
William Valdar ◽  
...  

Obesity in human populations, currently a serious health concern, is considered to be the consequence of an energy imbalance in which more energy in calories is consumed than is expended. We used interval mapping techniques to investigate the genetic basis of a number of energy balance traits in an F11 advanced intercross population of mice created from an original intercross of lines selected for increased and decreased heat loss. We uncovered a total of 137 quantitative trait loci (QTLs) for these traits at 41 unique sites on 18 of the 20 chromosomes in the mouse genome, with X-linked QTLs being most prevalent. Two QTLs were found for the selection target of heat loss, one on distal chromosome 1 and another on proximal chromosome 2. The number of QTLs affecting the various traits generally was consistent with previous estimates of heritabilities in the same population, with the most found for two bone mineral traits and the least for feed intake and several body composition traits. QTLs were generally additive in their effects, and some, especially those affecting the body weight traits, were sex-specific. Pleiotropy was extensive within trait groups (body weights, adiposity and organ weight traits, bone traits) and especially between body composition traits adjusted and not adjusted for body weight at sacrifice. Nine QTLs were found for one or more of the adiposity traits, five of which appeared to be unique. The confidence intervals among all QTLs averaged 13.3 Mb, much smaller than usually observed in an F2 cross, and in some cases this allowed us to make reasonable inferences about candidate genes underlying these QTLs. This study combined QTL mapping with genetic parameter analysis in a large segregating population, and has advanced our understanding of the genetic architecture of complex traits related to obesity.


2014 ◽  
Author(s):  
Larry Leamy ◽  
Kari Elo ◽  
Merlyn K Nielsen ◽  
Stephanie Thorn ◽  
William Valdar ◽  
...  

Obesity in human populations, currently a serious health concern, is considered to be the consequence of an energy imbalance in which more energy in calories is consumed than is expended. We used interval mapping techniques to investigate the genetic basis of a number of energy balance traits in an F11 advanced intercross population of mice created from an original intercross of lines selected for increased and decreased heat loss. We uncovered a total of 137 quantitative trait loci (QTLs) for these traits at 41 unique sites on 18 of the 20 chromosomes in the mouse genome, with X-linked QTLs being most prevalent. Two QTLs were found for the selection target of heat loss, one on distal chromosome 1 and another on proximal chromosome 2. The number of QTLs affecting the various traits generally was consistent with previous estimates of heritabilities in the same population, with the most found for two bone mineral traits and the least for feed intake and several body composition traits. QTLs were generally additive in their effects, and some, especially those affecting the body weight traits, were sex-specific. Pleiotropy was extensive within trait groups (body weights, adiposity and organ weight traits, bone traits) and especially between body composition traits adjusted and not adjusted for body weight at sacrifice. Nine QTLs were found for one or more of the adiposity traits, five of which appeared to be unique. The confidence intervals among all QTLs averaged 13.3 Mb, much smaller than usually observed in an F2 cross, and in some cases this allowed us to make reasonable inferences about candidate genes underlying these QTLs. This study combined QTL mapping with genetic parameter analysis in a large segregating population, and has advanced our understanding of the genetic architecture of complex traits related to obesity.


Genetics ◽  
1999 ◽  
Vol 152 (2) ◽  
pp. 699-711 ◽  
Author(s):  
D E Moody ◽  
D Pomp ◽  
M K Nielsen ◽  
L D Van Vleck

Abstract Energy balance is a complex trait with relevance to the study of human obesity and maintenance energy requirements of livestock. The objective of this study was to identify, using unique mouse models, quantitative trait loci (QTL) influencing traits that contribute to variation in energy balance. Two F2 resource populations were created from lines of mice differing in heat loss measured by direct calorimetry as an indicator of energy expenditure. The HB F2 resource population originated from a cross between a noninbred line selected for high heat loss and an inbred line with low heat loss. Evidence for significant QTL influencing heat loss was found on chromosomes 1, 2, 3, and 7. Significant QTL influencing body weight and percentage gonadal fat, brown fat, liver, and heart were also identified. The LH F2 resource population originated from noninbred lines of mice that had undergone divergent selection for heat loss. Chromosomes 1 and 3 were evaluated. The QTL for heat loss identified on chromosome 1 in the HB population was confirmed in the LH population, although the effect was smaller. The presence of a QTL influencing 6-wk weight was also confirmed. Suggestive evidence for additional QTL influencing heat loss, percentage subcutaneous fat, and percentage heart was found for chromosome 1.


2000 ◽  
Vol 11 (10) ◽  
pp. 824-830 ◽  
Author(s):  
Akira Ishikawa ◽  
Yoichi Matsuda ◽  
Takao Namikawa

1997 ◽  
Vol 70 (2) ◽  
pp. 117-124 ◽  
Author(s):  
KELLIE A. RANCE ◽  
WILLIAM G. HILL ◽  
PETER D. KEIGHTLEY

Evidence of a large sex-linked effect accounting for 25% of the divergence between mouse lines selected for body weight has been described previously. A marker-based study was undertaken to determine the number and map positions of the putative X-linked quantitative trait loci (QTLs). An F2 population was generated from a reciprocal F1 between an inbred low line derived from the low selection line and the high selection line. To enable inference of marker-associated QTL effects on the X chromosome, an analytical technique was developed based on the multiple regression method of Haley and Knott. The analysis of data on 10 week weight indicated a single QTL of large effect situated at about 23 cM from the proximal end of the chromosome, with a peak LOD score of 24·4. The likelihood curve showed a single well-defined peak, and gave a 95% confidence interval for the QTL location of 8 cM. The estimates for the additive genotypic effects in males and females (half the differences between hemizygous males and between homozygous females) were 2·6 g in both cases, or 17% and 20% of the 10 week body weight in males and females respectively. Dominance effects in the females were found to be non-significant. No significant X-linked effect on carcass fat percentage was detected, but a single X-linked QTL appears to explain almost the entire X-linked body weight effect.


2003 ◽  
Vol 76 (2) ◽  
pp. 155-165 ◽  
Author(s):  
G.J. Lee ◽  
A.L. Archibald ◽  
G.B. Garth ◽  
A.S. Law ◽  
D. Nicholson ◽  
...  

AbstractData from the F2 generation of a Large White (LW) ✕ Meishan (MS) crossbred population were analysed to detect quantitative trait loci (QTL) for leg and gait scores, osteochondrosis and physis scores. Legs, feet and gait score were assessed in 308 F2 animals at 85 ( + 5) kg and osteochondrosis and physis scores were recorded for the right foreleg after slaughter. A genome scan was performed using 111 genetic markers chosen to span the genome that were genotyped on the F2 animals and their F1 parents and purebred grandparents. A QTL on chromosome 1 affecting gait score was significant at the genome-wide significance level. Additional QTL significant at the chromosome-wide 5% threshold level (approx. equivalent to the genome-wide suggestive level) were detected on chromosome 1 for front feet and back legs scores, on chromosome 13 for front legs and front feet scores, on chromosome 14 for front legs, front feet and back legs scores and on chromosome 15 for back feet score. None of the QTL for osteochondrosis score exceeded the chromosome-wide suggestive level, but one chromosome-wide QTL for physis score was found on chromosome 7. On chromosome 1, gait and front feet scores mapped to the middle of the chromosome and showed additive effects in favour of the LW alleles and no dominance effects. The QTL for back legs score mapped to the distal end of the chromosome and showed a dominant effect and no additive effect. On chromosomes 14 and 15, the LW allele was again superior to the MS allele. On chromosome 13, there were both additive and dominance effects in favour of the MS allele. The MS alleles on chromosome 13 may have potential for introgression into a commercial LW population. The other putative QTLs identified may have value in marker-assisted selection in LW or MS-synthetic populations.


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