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M. J. Argente - One of the best experts on this subject based on the ideXlab platform.
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Correlated response in Litter Size components in rabbits selected for Litter Size variability
Journal of Animal Breeding and Genetics, 2017Co-Authors: M. J. Argente, E. W. Calle, M. L. García, Agustín BlascoAbstract:Summary A divergent selection experiment for the environmental variability of Litter Size (Ve) over seven generations was carried out in rabbits at the University Miguel Hernandez of Elche. The Ve was estimated as the phenotypic variance within the female, after correcting for year-season and parity-lactation status. The aim of this study was to analyse the correlated responses to selection in Litter Size components. The ovulation rate (OR) and number of implanted embryos (IE) in females were measured by laparoscopy at 12 day of the second gestation. At the end of the second gestation, the total number of kits born was measured (TB). Embryonic (ES), foetal (FS) and prenatal (PS) survival were computed as IE/OR, TB/IE and TB/OR, respectively. A total of 405 laparoscopies were performed. Data were analysed using Bayesian methodology. The correlated response to selection for Litter Size environmental variability in terms of the Litter Size components was estimated as either genetic trends, estimated by computing the average estimated breeding values for each generation and each line, or the phenotypic differences between lines. The OR was similar in both lines. However, after seven generations of selection, the homogenous line showed more IE (1.09 embryos for genetic means and 1.23 embryos for phenotypic means) and higher ES than the heterogeneous one (0.07 for genetic means and 0.08 for phenotypic means). The probability of the phenotypic differences between lines being higher than zero (p) was 1.00 and .99, respectively. A higher uterine overcrowding of embryos in the homogeneous line did not penalize FS; as a result, this line continued to show a greater TB (1.01 kits for genetic means and 1.30 kits for phenotypic means, p = .99, in the seventh generation). In conclusion, a decrease in Litter Size variability showed a favourable effect on ES and led to a higher Litter Size at birth.
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selection for environmental variance of Litter Size in rabbits
Genetics Selection Evolution, 2017Co-Authors: Agustín Blasco, M. L. García, M Martinezalvaro, Noelia Ibanezescriche, M. J. ArgenteAbstract:Abstract Background In recent years, there has been an increasing interest in the genetic determination of environmental variance. In the case of Litter Size, environmental variance can be related to the capacity of animals to adapt to new environmental conditions, which can improve animal welfare. Results We developed a ten-generation divergent selection experiment on environmental variance. We selected one line of rabbits for Litter Size homogeneity and one line for Litter Size heterogeneity by measuring intra-doe phenotypic variance. We proved that environmental variance of Litter Size is genetically determined and can be modified by selection. Response to selection was 4.5% of the original environmental variance per generation. Litter Size was consistently higher in the Low line than in the High line during the entire experiment. Conclusions We conclude that environmental variance of Litter Size is genetically determined based on the results of our divergent selection experiment. This has implications for animal welfare, since animals that cope better with their environment have better welfare than more sensitive animals. We also conclude that selection for reduced environmental variance of Litter Size does not depress Litter Size.
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Major Components in Limiting Litter Size
Insights from Animal Reproduction, 2016Co-Authors: M. J. ArgenteAbstract:The Litter Size is an important trait in prolific species such as rabbits and pigs. However, selection on Litter Size has had limited success in these species because of its low heritabil‐ ity and sex-limited expression. The Litter Size is a complex physiological trait in prolific species, affected by several components that are expressed sequentially, for example, ov‐ ulation, fertilization, embryo development, and fetal survival. The selection for ovulation rate or/and prenatal survival has been proposed to improve Litter Size indirectly. Howev‐ er, these alternative methods have not reached the expected response rate. Implantation is also a critical point in successful gestation, one-third to one-half of prenatal mortality occurring during peri-implantation. The uterus must provide an adequate microenviro‐ ment for the growth and development of embryo and for receptivity to implantation. There are multitudes of cellular events involved in crosstalk between embryo and mater‐ nal uterus during peri-implantation. A better understanding of molecular mechanisms af‐ fecting the implantation process could help to propose new strategies for Litter Size improvement in prolific species.
James M Cheverud - One of the best experts on this subject based on the ideXlab platform.
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epistasis affecting Litter Size in mice
Journal of Evolutionary Biology, 2004Co-Authors: Andrea C Peripato, R A De Brito, Sergio Russo Matioli, L S Pletscher, Ty T Vaughn, James M CheverudAbstract:Litter Size is an important reproductive trait as it makes a major contribution to fitness. Generally, traits closely related to fitness show low heritability perhaps because of the corrosive effects of directional natural selection on the additive genetic variance. Nonetheless, low heritability does not imply, necessarily, a complete absence of genetic variation because genetic interactions (epistasis and dominance) contribute to variation in traits displaying strong heterosis in crosses, such as Litter Size. In our study, we investigated the genetic architecture of Litter Size in 166 females from an F2 intercross of the SM/J and LG/J inbred mouse strains. Litter Size had a low heritability (h2 = 12%) and a low repeatability (r = 33%). Using interval-mapping methods, we located two quantitative trait loci (QTL) affecting Litter Size at locations D7Mit21 + 0 cM and D12Mit6 + 8 cM, on chromosomes 7 and 12 respectively. These QTL accounted for 12.6% of the variance in Litter Size. In a two-way genome-wide epistasis scan we found eight QTL interacting epistatically involving chromosomes 2, 4, 5, 11, 14, 15 and 18. Taken together, the QTL and their interactions explain nearly 49% (39.5% adjusted multiple r2) of the phenotypic variation for Litter Size in this cross, an increase of 36% over the direct effects of the QTL. This indicates the importance of epistasis as a component of the genetic architecture of Litter Size and fitness in our intercross population.
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Genetic and environmental impacts on Litter Size and early infant survival in three species of callitrichids
Journal of Heredity, 1996Co-Authors: Cashell E. Jaquish, James M Cheverud, S. D. TardifAbstract:Callitrichids are unusual among anthropoid primates in that they can deliver one to four offspring per Litter in captivity. Factors underlying intraspecific variation in Litter Size are unclear. Data from the Oak Ridge Associated Universities (ORAU) Marmoset Research Center provided an opportunity to investigate determinants of variation in (1) average Litter Size at birth and (2) average Litter Size surviving to 2 weeks of age in Saguinus fuscicollis, S. oedipus, and Callithrix jacchus. The objectives were to (1) investigate the impact of parity, husbandry, origin (wild or captive), and subspecific hybridization on phenotypic variance in Litter Size and (2) to estimate the heritability of Litter Size at birth and at 14 days. Husbandry changes were the only significant covariate and increased Litter Size at birth in C. jacchus only. Heritability estimates for average Litter Size at birth were significant only in S. fuscicollis (h2 = 0.306). Heritability of average Litter Size at 2 weeks of age was not significantly greater than zero. Estimates of genetic variability were relatively high, however both traits had very high levels of residual variance. The results suggest that Litter Size is a malleable trait that may respond to environmental factors.
R A De Brito - One of the best experts on this subject based on the ideXlab platform.
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epistasis affecting Litter Size in mice
Journal of Evolutionary Biology, 2004Co-Authors: Andrea C Peripato, R A De Brito, Sergio Russo Matioli, L S Pletscher, Ty T Vaughn, James M CheverudAbstract:Litter Size is an important reproductive trait as it makes a major contribution to fitness. Generally, traits closely related to fitness show low heritability perhaps because of the corrosive effects of directional natural selection on the additive genetic variance. Nonetheless, low heritability does not imply, necessarily, a complete absence of genetic variation because genetic interactions (epistasis and dominance) contribute to variation in traits displaying strong heterosis in crosses, such as Litter Size. In our study, we investigated the genetic architecture of Litter Size in 166 females from an F2 intercross of the SM/J and LG/J inbred mouse strains. Litter Size had a low heritability (h2 = 12%) and a low repeatability (r = 33%). Using interval-mapping methods, we located two quantitative trait loci (QTL) affecting Litter Size at locations D7Mit21 + 0 cM and D12Mit6 + 8 cM, on chromosomes 7 and 12 respectively. These QTL accounted for 12.6% of the variance in Litter Size. In a two-way genome-wide epistasis scan we found eight QTL interacting epistatically involving chromosomes 2, 4, 5, 11, 14, 15 and 18. Taken together, the QTL and their interactions explain nearly 49% (39.5% adjusted multiple r2) of the phenotypic variation for Litter Size in this cross, an increase of 36% over the direct effects of the QTL. This indicates the importance of epistasis as a component of the genetic architecture of Litter Size and fitness in our intercross population.
Agustín Blasco - One of the best experts on this subject based on the ideXlab platform.
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Correlated response in Litter Size components in rabbits selected for Litter Size variability
Journal of Animal Breeding and Genetics, 2017Co-Authors: M. J. Argente, E. W. Calle, M. L. García, Agustín BlascoAbstract:Summary A divergent selection experiment for the environmental variability of Litter Size (Ve) over seven generations was carried out in rabbits at the University Miguel Hernandez of Elche. The Ve was estimated as the phenotypic variance within the female, after correcting for year-season and parity-lactation status. The aim of this study was to analyse the correlated responses to selection in Litter Size components. The ovulation rate (OR) and number of implanted embryos (IE) in females were measured by laparoscopy at 12 day of the second gestation. At the end of the second gestation, the total number of kits born was measured (TB). Embryonic (ES), foetal (FS) and prenatal (PS) survival were computed as IE/OR, TB/IE and TB/OR, respectively. A total of 405 laparoscopies were performed. Data were analysed using Bayesian methodology. The correlated response to selection for Litter Size environmental variability in terms of the Litter Size components was estimated as either genetic trends, estimated by computing the average estimated breeding values for each generation and each line, or the phenotypic differences between lines. The OR was similar in both lines. However, after seven generations of selection, the homogenous line showed more IE (1.09 embryos for genetic means and 1.23 embryos for phenotypic means) and higher ES than the heterogeneous one (0.07 for genetic means and 0.08 for phenotypic means). The probability of the phenotypic differences between lines being higher than zero (p) was 1.00 and .99, respectively. A higher uterine overcrowding of embryos in the homogeneous line did not penalize FS; as a result, this line continued to show a greater TB (1.01 kits for genetic means and 1.30 kits for phenotypic means, p = .99, in the seventh generation). In conclusion, a decrease in Litter Size variability showed a favourable effect on ES and led to a higher Litter Size at birth.
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selection for environmental variance of Litter Size in rabbits
Genetics Selection Evolution, 2017Co-Authors: Agustín Blasco, M. L. García, M Martinezalvaro, Noelia Ibanezescriche, M. J. ArgenteAbstract:Abstract Background In recent years, there has been an increasing interest in the genetic determination of environmental variance. In the case of Litter Size, environmental variance can be related to the capacity of animals to adapt to new environmental conditions, which can improve animal welfare. Results We developed a ten-generation divergent selection experiment on environmental variance. We selected one line of rabbits for Litter Size homogeneity and one line for Litter Size heterogeneity by measuring intra-doe phenotypic variance. We proved that environmental variance of Litter Size is genetically determined and can be modified by selection. Response to selection was 4.5% of the original environmental variance per generation. Litter Size was consistently higher in the Low line than in the High line during the entire experiment. Conclusions We conclude that environmental variance of Litter Size is genetically determined based on the results of our divergent selection experiment. This has implications for animal welfare, since animals that cope better with their environment have better welfare than more sensitive animals. We also conclude that selection for reduced environmental variance of Litter Size does not depress Litter Size.
J.g. Wang - One of the best experts on this subject based on the ideXlab platform.
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Polymerisation effects of four microsatellites on Litter Size in Xinong Saanen goats
Animal Production Science, 2015Co-Authors: J.g. Wang, X.p. AnAbstract:In this study, the polymerisation effects of four microsatellites (OarAE101, BM1329, BM143 and LSCV043) on Litter Size in Xinong Saanen goats were analysed by means of microsatellite marker and pedigrees, then associations between combined genotypes and Litter Size were performed. The results indicate that the individuals with A5A1B10B5C5C1D6D2 (3.10 ± 0.07) had greater Litter Sizes than those with other combined genotypes in terms of average parity (P < 0.05). Comparing A5A1B10B5C5C1D6D2 with A7A2B10B5C5C1D6D2, the polymerisation effect value of the A5A1 genotype Litter Size was 18.09% higher than that of the A7A2 genotype. Comparing A5A1B6B1C6C1D6D2 of the F1 generation with A5A1B6B1C7C3D6D2 of the F2 generation, it was shown that the polymerisation effect value of the C6C1 genotype was 37.93% higher than that of the C7C3 genotype. Comparing A5A1B6B1C8C4D4D1 of the F1 generation with A5A1B6B1C8C4D9D5 of the F2 generation, it was shown that the polymerisation effect value of the D4D1 genotype was 68.07% higher than that of the D9D5 genotype. These results suggested that A5A1B10B5C5C1D6D2 is a useful marker affecting caprine Litter Size.
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polymorphism identification in goat gnrh1 and gdf9 genes and their association analysis with Litter Size
Animal Genetics, 2013Co-Authors: X.p. An, H B Zhao, Guang Li, J Y Peng, Y X Song, J.g. WangAbstract:Summary This study investigated the polymorphisms of GNRH1 and GDF9 genes in 641 goats of three breeds: Xinong Saanen, Guanzhong and Boer. Two allelic variants were identified in the GNRH1 gene (JN645280:g.3548A>G and JN645281:g.3699G>A) and one allelic variant was found in the GDF9 gene (JN655693:g.4093G>A). Furthermore, g.4093G>A was a missense mutation (p.Val397Ile of GDF9). Results of an association analysis indicated that SNPs g.3548A>G and g.4093G>A had significant effects on Litter Size (P G, g.3699G>A and g.4093G>A also affected Litter Size with the C5 genotype having the highest Litter Size in the first, third, fourth and average parity. Hence, the biochemical and physiological functions, together with the results obtained in our investigation, suggest that the GNRH1 and GDF9 genes could serve as genetic markers for Litter Size in goat breeding.
