Morteza Mahdavi; Gholam Reza Dashab; Mehdi Vafaye Valleh; Mohammad Rokouei; Mehdi Sargolzaei
Abstract
The optimization of the reference population in genomic evaluation plays an important role in livestock breeding, because of its potential impact on the accuracy of estimating the marker effects and genomic breeding values. In the present study, seven different train set selection methods including selection ...
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The optimization of the reference population in genomic evaluation plays an important role in livestock breeding, because of its potential impact on the accuracy of estimating the marker effects and genomic breeding values. In the present study, seven different train set selection methods including selection of all, selection of the highest and lowest performances, random selection, selection of individuals with the most and least marker and QTL similarity were evaluated. In genome wide association study selection of all as train set detected common SNPs which make a high variation on the trait. However selective train set was just reported rare SNPs with a major effect on the trait. In genomic selection simultaneous use of high-density markers and selective train set in comparison with low-density and selection of all as train set reduced accuracy, but did not change the ranking of animals. There was also an interaction between train set selection method and generation (P≤0.0134) as well as the linkage disequilibrium (P≤ 2e-16). In general, selection of all animals as a train set resulted in higher accuracy compared to six selective train set methods. There were no differences between the methods of selecting train set in populations with a low effective size (r2 = 0.255, Ne =100), but in populations with a high effective size (r2 = 0.086, Ne =400) methods, with different accuracy predicted genomic breeding values. The highest and lowest accuracy were respectively belonged to most QTL and marker similarity methods.
h. Faraji; Khadijeh Ebrahimi; Gholam Reza Dashab; Mohammad Rokouei
Abstract
Body weight is one of the important economic traits in the breeding program of broiler species. The genetic parameters of each population are affected by different environmental conditions. Therefore, each breeding activity in a poultry is required to estimate these parameters. The aim of this study ...
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Body weight is one of the important economic traits in the breeding program of broiler species. The genetic parameters of each population are affected by different environmental conditions. Therefore, each breeding activity in a poultry is required to estimate these parameters. The aim of this study was to estimate the genetic parameters of body weight from hatch to 45 days old of the crossbred population of Japanese quail by using of 1794 records of body weight from 70 males and 72 females. Estimation of genetic and non-genetic parameters was performed using a multi-trait model including additive, non-additive and maternal effects via Gibbs sampling. Estimated heritability for body weight in hatch, 5, 10, 15, 20, 25, 30, 35, 40, and 45 days’ was 0.16, 0.11, 0.12, 0.14, 0.15, 0.18, 0.20, 0.19, 0.17 and 0.17, respectively. The range of heritability for maternal genetic, the ratio of maternal permanent environmental, dominance, and epistasis variance to phenotypic variance varied between 0.32-0.39, 0.23-0.36, 0.04-0.10, and 0.03-0.13, respectively. The highest value for genetic correlation was estimated between body weight in 35 and 30 days (0.94) and the lowest value was between hatching weight and 5 days (0.16). The results showed that the maternal and non-additive effects must be fit into the model for accurate estimation of genetic parameters, and the selection of quail for body weight of 25 days due to its high correlation with 45 days and its high heritability could result in a good genetic improvement in the body weight of 45 days.
Hossein Moradgholi; Gholam Reza Dashab; Mehdi Vafa Valleh
Abstract
Sistani beef cattle is a native breed of east of Iran that as a valuable genetic resource in the tropical area could be good a candidate to produce high quantity of muscular carcass portions with high efficiency. In order to explore the Mitochondrial transcription factor ...
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Sistani beef cattle is a native breed of east of Iran that as a valuable genetic resource in the tropical area could be good a candidate to produce high quantity of muscular carcass portions with high efficiency. In order to explore the Mitochondrial transcription factor A gene (TFAM) polymorphisms using PCR-RFLP, 150 Sistani cows were randomly selected and then blood samples were taken from the jugular vein of each animal individually. Thereafter, blood samples were salting-out and electrophoresed with 1% agarose gel. The position of the TFAM promoter region amplified by PCR and PCR products with 801bp length were sliced by BsuRI enzyme. Digestion products on 3% agarose gel were shown by electrophoresis and staining with ethidium bromide. The patterns of digestion in AA homozygotes, CC homozygotes, and AC heterozygotes were as follows: three bands with 152, 187, and 462bp; four bands with 83, 104, 152, and 462bp; and five bands with 83, 104, 152, 187, and 462bp, respectively. The results showed that the position of TFAM population deviated from the Hardy-Weinberg equilibrium (P <0.05). Shannon index (I), Nei index, observed heterozygosity, and expected heterozygosity were 0.69, 0.49, 0.37, and 0.50, respectively. In conclusion, no significant differences between genotypes of Sistani cattle were observed for TFAM gene polymorphism and growth traits.
Gh.R. Dashab; A.A. Aslaminejad; M.R. Nasiri; A. Asmailizadeh; D. Ali Saghi
Abstract
A total of 47672 greasy fleece weight records belonging to 13,758 Baluchi sheep (progenies of 491 sires and 8109 dams) collected during 28 years (1983-2010); and also 926 wool samples from 13 half sib families and their dams from two flocks of Abbas-Abad breeding centre were used in analysis. The effects ...
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A total of 47672 greasy fleece weight records belonging to 13,758 Baluchi sheep (progenies of 491 sires and 8109 dams) collected during 28 years (1983-2010); and also 926 wool samples from 13 half sib families and their dams from two flocks of Abbas-Abad breeding centre were used in analysis. The effects of sex, year and season of shearing, litter size (single, twin and multiple) and herds (two class include one and two) on fleece weight and wool fibre characterstics were evaluated. Birth year had significant effect on most of wool traits except for the percent of true wool, medullated, hetero-type fibers and percent of fibers between 40 to 50 microns. Greasy fleece weight and staple length was higher in males compared with females. Year and season of shearing had significant effect on greasy fleece weight. The average fiber diameter was different between two flock of Baluchi sheep. Animal repeated model and animal model were used for genetic analysis of greasy fleece weight and quality traits of fleece, respectively. Heritability and repeatability of greasy fleece weight were 0.13 and 0.27, respectively. Heritability of wool quality traits i.e. staple length, wool yield, average fibers diameter, coefficient of variation of fibers diameter in sample and the percent of true, medullated and hetero-type wool were 0.48, 0.23, 0.32, 0.24, 0.65, 0.20 and 0.16, respectively. The average breeding values from base year (1983) to the final year (2010) was increased by 93.2 gram per year. The results showed that selection for increasing body weight over 28 years has led to an increase in greasy fleece weight, but had no effect on quality traits. Therefore, the use of quality traits in breeding programs will lead to an improved fiber quality
