The impact of racial pattern on the genetic improvement of Morada Nova sheep

2016 ◽  
Vol 58 ◽  
pp. 73-82 ◽  
Author(s):  
L. Shiotsuki ◽  
P.H.T. Silva ◽  
K.M. Silva ◽  
A.V. Landim ◽  
O.R. Morais ◽  
...  
Keyword(s):  
Birth Weight ◽  
Genetic Improvement ◽  
Coat Colour ◽  
Simulated Population ◽  
Response To Selection ◽  
Selection For ◽  
Productive Traits ◽  
Red Variety ◽  
The Impact ◽  
Selection Of

SummaryThe objective of the present study was to describe the frequency of the main racial traits of Morada Nova sheep and simulate the impact of this culling on the response to selection for birth weight. The data from sex, coat colour, hoof pigmentation, muzzle pigmentation, polled and cryptorchidism were collected individually at weaning from 385 Morada Nova sheep of the red variety, born between 2010 and 2012, which belonged to four different flocks in the state of Ceará, Brazil. To estimate the impact of culling of animals due to racial pattern on the genetic improvement of the Morada Nova population, the genetic gains in birth weight per generation were calculated considering the following different scenarios of culling due to racial pattern in a simulated population. The present results indicate that the most urgent step is flexibilization of the requirement of dark muzzles and hooves. The selection of Morada Nova sheep based on racial pattern has caused losses in the genetic gain for productive traits such as birth weight. Readaptation of the official racial pattern established for Morada Nova sheep is necessary so that the racial pattern is achieved and an adequate number of animals will be available for selection.

scholarly journals Parameters and determinants of responses to selection in antibody libraries

2021 ◽  
Vol 17 (3) ◽  
pp. e1008751
Author(s):  
Steven Schulz ◽  
Sébastien Boyer ◽  
Matteo Smerlak ◽  
Simona Cocco ◽  
Rémi Monasson ◽  
...  
Keyword(s):  
Affinity Maturation ◽  
Response To Selection ◽  
Evolutionary Potential ◽  
Term Evolution ◽  
A Genome ◽  
Antibody Libraries ◽  
Selection For ◽  
The Impact ◽  
Selection Of

The sequences of antibodies from a given repertoire are highly diverse at few sites located on the surface of a genome-encoded larger scaffold. The scaffold is often considered to play a lesser role than highly diverse, non-genome-encoded sites in controlling binding affinity and specificity. To gauge the impact of the scaffold, we carried out quantitative phage display experiments where we compare the response to selection for binding to four different targets of three different antibody libraries based on distinct scaffolds but harboring the same diversity at randomized sites. We first show that the response to selection of an antibody library may be captured by two measurable parameters. Second, we provide evidence that one of these parameters is determined by the degree of affinity maturation of the scaffold, affinity maturation being the process by which antibodies accumulate somatic mutations to evolve towards higher affinities during the natural immune response. In all cases, we find that libraries of antibodies built around maturated scaffolds have a lower response to selection to other arbitrary targets than libraries built around germline-based scaffolds. We thus propose that germline-encoded scaffolds have a higher selective potential than maturated ones as a consequence of a selection for this potential over the long-term evolution of germline antibody genes. Our results are a first step towards quantifying the evolutionary potential of biomolecules.

scholarly journals Efficiency of crosses selection for yield in red rice through diallel analysis

2021 ◽  
Vol 7 ◽  
pp. 1-10
Author(s):  
Ricardo Montalván Del Águila ◽  
Edson Ferreira Silva
Keyword(s):  
Early Identification ◽  
Genetic Improvement ◽  
Diallel Analysis ◽  
Inbred Lines ◽  
Red Rice ◽  
Self Fertilization ◽  
Selection For ◽  
Selection Of

Diallel analysis is a methodology used in the genetic improvement of plants. One of its main purposes is to provide subsidies for early identification of promising crosses for the development of high yielding inbred lines. Several articles have been published in diallel analysis, and many recommendations were made either for the selection of certain crosses of lines for hybrids or for the development of competitive inbred lines. However, articles about the validation of information predicted by these analyses and the results in the field are scarce or nonexistent. The objective of this article was to validate diallel analysis using model IV of Gardner and Eberhart published in 1966, a methodology recommended to identify promising crosses among developed inbred lines in red rice. We compared the recommendations of the diallel analysis crosses with the process end the result of inbreeding generations. Recommended crosses by the diallel analysis were different from those obtained after generations of self-fertilization and selection. However, two of the four selected parents were matched. Considerations were made about the accuracy of diallel analysis and the need to validate in practice methodologies that theoretically are of great value.

scholarly journals The genetic analysis of the direct and correlated response to selection for chaetae in Drosophila melanogaster

1973 ◽  
Vol 22 (1) ◽  
pp. 1-7
Author(s):  
W. R. Scowcroft
Keyword(s):  
Drosophila Melanogaster ◽  
Genetic Analysis ◽  
Genetic Correlation ◽  
Statistical Approach ◽  
Correlated Response ◽  
Minor Importance ◽  
Response To Selection ◽  
Genetic Changes ◽  
Selection For ◽  
Selection Of

SUMMARYThe direct and correlated response to selection of scutellar microchaetae and scutellar bristles has been analysed by determining the contribution of the three major chromosomes, alone and in combination with each other, to the overall response. The results of the analysis confirm a previous finding, based on a formal statistical approach, that response to selection for microchaetae had highly pleiotropic effects on scutellar bristles. In lines selected, each for high and low microchaetae, genetic changes in the 2nd and 3rd chromosomes are pre-eminent and essentially equal. Inter-chromosomal interactions are of relatively minor importance in interpreting the response to selection for microchaetae but assume greater importance with respect to the correlated character. The results are discussed in terms of the genetic correlation between fitness and the character measured.

The effect of selection for litter size and litter weight at weaning in mice maintained on two diets

1963 ◽  
Vol 5 (3) ◽  
pp. 317-326 ◽  
Author(s):  
D. C. Dalton ◽  
T. L. Bywater
Keyword(s):  
Litter Size ◽  
Genetic Improvement ◽  
Random Mating ◽  
The Other ◽  
Response To Selection ◽  
Control Groups ◽  
Litter Weight ◽  
Dietary Switch ◽  
Selection For ◽  
Time Selection

SUMMARYAn experiment was carried out with mice over 24 generations to measure the response obtained to selection for litter size and litter weight at weaning on two dietary regimes designated normal and diluted. In addition, control groups bred by random mating were maintained on each diet. The stock were maintained on the diets from generation 0–3 after which time selection for the traits started and continued up to generation 17. After generation 17 for a further 6 generations, all selection stopped and half of each group was switched on to the other diet, while the remaining half continued as before.No significant response was obtained to selection for either litter size or litter weight at weaning.The diets provided did not bring about a differential response to selection for the traits, and the response to the dietary switch was small and temporary in its effect.Due to strong maternal effects and low heritability, little genetic improvement was obtained by selection for litter size and litter weight at weaning in these mice.

scholarly journals Parameters and determinants of responses to selection in antibody libraries

2019 ◽  
Author(s):  
Steven Schulz ◽  
Sébastien Boyer ◽  
Matteo Smerlak ◽  
Simona Cocco ◽  
Rémi Monasson ◽  
...  
Keyword(s):  
Adaptive Immune Response ◽  
Evolutionary Process ◽  
Affinity Maturation ◽  
Target Antigen ◽  
Response To Selection ◽  
Evolutionary Potential ◽  
Information Theoretic ◽  
Antibody Libraries ◽  
The Impact ◽  
Selection Of

AbstractAntibody repertoires contain binders to nearly any target antigen. The sequences of these antibodies differ mostly at few sites located on the surface of a scaffold that itself consists of much less varied amino acids. What is the impact of this scaffold on the response to selection of a repertoire? To gauge this impact, we carried out quantitative phage display experiments with three antibody libraries based on distinct scaffolds harboring the same diversity at randomized sites, which we selected for binding to four arbitrary targets. We first show that the response to selection of an antibody library is captured by a simple and measurable parameter with direct physical and information-theoretic interpretations. Second, we identify a major determinant of this parameter which is encoded in the scaffold, its degree of evolutionary maturation. Antibodies undergo an accelerated evolutionary process, called affinity maturation, to improve their affinity to a given target antigen as part of the adaptive immune response. We find that libraries of antibodies built around such maturated scaffolds have a lower response to selection to other arbitrary targets than libraries built around naïve scaffolds of germline origin. Our results are a first step towards quantifying and controlling the evolutionary potential of biomolecules.

Using Pelvic Areas and Linear Body Measurements in the Selection for Reduced Dystocia Rates in Sussex Heifers

2021 ◽  
Author(s):  
L. Bila ◽  
P.J. Fourie ◽  
T.L. Tyasi
Keyword(s):  
Birth Weight ◽  
South African ◽  
Body Measurements ◽  
Health Issues ◽  
Knowledge Use ◽  
Cattle Industry ◽  
Selection For ◽  
Economical Losses ◽  
Selection Of ◽  
Linear Body

Background: Dystocia in cattle is a global problem which causes many health issues and economical losses in the beef cattle industry. However, to the greatest of our knowledge, use of pelvic areas and linear body measurements in South African Sussex heifers has not yet been reported on literature. Hence, the aim of this study was to use pelvic areas and linear body measurements in the selection of replacement Sussex heifers to reduce dystocia amongst heifers, while improving ease of calving.Methods: One hundred eighty-six first calf Sussex heifers 24 months old, weighing approximately 437 kg were used for this study. A number of six, two-year-old bulls, weighing approximately 800 kg were used for mating the 135 heifers during the first trial with a bull to cow ratio of (1:35; 1:35, 1;35 and 1:30). The second trial consisted of 51 heifers with a number two, two-year-old bulls respectively, with a bull to cow ratio of (1:30 and 1:21).Result: A significant correlation between calving eases score and calf gender, r = -0.35 was revealed. The chances of a heifer to experience dystocia were more when a male calf was born. Birth weight, revealed that higher the birth weight higher the probability of a heifer to experience dystocia. It can be concluded that pelvic measurements in Sussex heifers may be a valuable tool to reduce dystocia.

The effect of correction factors on response to selection in beef cattle

1980 ◽  
Vol 30 (2) ◽  
pp. 211-216 ◽  
Author(s):  
L. P. Jones ◽  
I. R. Hopkins
Keyword(s):  
Growth Rate ◽  
Age Groups ◽  
Correction Factors ◽  
Response To Selection ◽  
Weaning Weight ◽  
Selection For ◽  
Rate Selection ◽  
Genetic Responses ◽  
Selection Differentials ◽  
Selection Of

ABSTRACTProgeny of younger dams grow more slowly than those of older dams. When the environmental effects of dam age are not allowed for in selection for growth rate, selection differentials and genetic responses to selection are reduced.In a model herd, with cows aged 2 to 8 years, it was found that neglecting the dam age effects reduced genetic gains by about 15% when selection is for weaning weight, and by 11 to 7 % when selection is at an age of 12 to 20 months. Much of the reduction occurs because of the selection of higher proportions from genetically inferior groups.If genetic differences among dam age groups are small the reduction is only 7% at weaning and less at older ages. The effect of ignoring calf age was also estimated. It was found that if calves born within a period of 33 days were compared and calf age was neglected, the response to selection for weaning weight would be reduced by about 6%.

Effectiveness of selection for growth rate in Zebu × British crossbred cattle. I. Pre-weaning growth

1975 ◽  
Vol 26 (2) ◽  
pp. 393 ◽  
Author(s):  
GW Seifert
Keyword(s):  
Growth Rate ◽  
Birth Weight ◽  
Environmental Effects ◽  
Significant Interaction ◽  
Response To Selection ◽  
Crossbred Cattle ◽  
Weaning Weight ◽  
Genetic Potential ◽  
Low Weight ◽  
Selection For

From random-bred populations of Africander cross (AX) and Brahman cross (BX), bulls and cows were selected within breeds for high and low weight per day of age (W/A) at c. 2 years of age and mated assortatively. There was a similar and significant response to selection in both breeds in birth weight and pre-weaning W/A as well as in pre-weaning gains. Although the BX animals were heavier and gained more than the AX animals, the differences were not as great or as consistent as the effect of selection. Calf gains were inversely related to cow gains from birth to weaning, but positively correlated to cow weight. During the pre-weaning period high W/A line cows gained significantly more than the low W/A line cows, while AX animals gained more than the BX group. The higher gain of the high W/A line cows and the higher weaning weight of their calves showed that these lines were more efficient than the low lines in terms of production of weaning weight. Very early calf gains from birth in November to January, and W/A in January, appeared to be poor indicators of the genetic potential of the calf and of the permanent environmental effects affecting its growth. In contrast, the period from January to March, during which the most rapid gains were experienced, reflected both the genetic potential and permanent environmental effects. The previous lactational status of the dam only affected birth weight and day of birth significantly and affected the AX calves more than the BX calves. This resulted in a significant interaction between breed and previous lactational status for these two traits.

scholarly journals Associations among individual gilt birth weight, litter birth weight phenotype, and the efficiency of replacement gilt production

2020 ◽  
Vol 98 (11) ◽  
Author(s):  
Jennifer Patterson ◽  
Mari L Bernardi ◽  
Matt Allerson ◽  
Aaron Hanson ◽  
Nick Holden ◽  
...  
Keyword(s):  
Birth Weight ◽  
Early Mortality ◽  
Selection Efficiency ◽  
Negative Effects ◽  
Breeding Management ◽  
Main Effect ◽  
Commercial Operation ◽  
Breeding Herd ◽  
Selection For ◽  
The Impact

Abstract Selection for larger litter size has increased the number of low individual birth weight (BWi) pigs and produced sows with a repeatable low average litter birth weight phenotype (BWP). Using an average of 3.6 litters records per sow, BWP was established in 644 nucleus-multiplication sows producing replacement gilts in a large commercial operation and classified as low (L-BWP, <1.18 kg, n = 85), medium (M-BWP, ≥1.18 to ≤1.35 kg, n = 250), or high (H-BWP, >1.35 kg, n = 309) on the basis of a BWi of 1.18 kg below which there was a high risk of early mortality and the average BWi (1.35 kg) for the population. In subsequent litters, potential replacement gilts born to these sows (n = 7,341) received a unique identification tag that allowed the impact of BWi, BWP, and their interactions on the efficiency of replacement gilt production to be evaluated. Negative effects of BWi on mortality until day 4 after birth were confirmed (P < 0.05) and cumulative losses to weaning, to day 70 of age, and to final pre-selection at 165 d of age were affected (P ≤ 0.05) by the interaction between BWP and BWi. Among the 2,035 gilts for which records for selection efficiency and production to fourth parity were available, a lower BWi decreased the probability of gilts reaching pubertal estrus (P < 0.05) after 21 and 28 d of boar stimulation starting at 180 d of age, with no effect of BWP. Overall, neither BWi, BWP, nor their interaction affected age at puberty. After breeding, only the main effect of BWP affected productivity and retention in the sow herd. In parities 1 and 2, percent stillborn was higher in litters born to gilts from H-BWP compared with L-BWP dams (P < 0.05), and in parity 2, total born and born alive were lower in sows derived from H-BWP compared with other BWPs. There were no differences in retention based on BWP classes until parity 2, after which retention tended (P ≤ 0.09) to be lower in sows derived from H-BWP compared with L-BWP dams. These results provide evidence that sow BWP is an important factor in the overall efficiency of replacement gilt management. This study also confirms that effective gilt selection and pre-breeding management protocols support excellent sow lifetime productivity and mitigate the risk of a high BWP in the litter of origin affecting retention in the breeding herd.

scholarly journals Impact of birth and rearing type, as well as inaccuracy of recording, on pre-weaning lamb phenotypic and genetic merit for live weight1

2017 ◽  
Vol 1 (2) ◽  
pp. 137-145 ◽  
Author(s):  
N. McHugh ◽  
T. Pabiou ◽  
K. McDermott ◽  
E. Wall ◽  
D. P. Berry
Keyword(s):  
Birth Weight ◽  
Average Daily Gain ◽  
Live Weight ◽  
Breeding Value ◽  
Parity Number ◽  
Recorded Data ◽  
Genetic Evaluations ◽  
The Impact ◽  
Selection Of ◽  
Birth Type

Abstract The objective of the present study was to quantify the impact of the systematic environmental effects of both birth and rearing type on pre-weaning lamb live weight, and to evaluate the repercussions of inaccurate recording of birth and rearing type on subsequent genetic evaluations. A total of 32,548 birth weight records, 35,770 forty-day weight records and 32,548 records for average daily gain (ADG) between birth and 40-day weight from the Irish national sheep database were used. For each lamb, a new variable, birth-rearing type, reflecting both the birth and rearing type of a lamb was generated by concatenating both parameters. The association between birth-rearing type and birth weight, 40-day weight, and ADG was estimated using linear mixed models. The repercussions of inaccurate recording of birth type were determined by quantifying the impact on sire estimated breeding value (EBV; with an accuracy of ≥ 35%), where one of the lambs born in a selection of twin litter births was assumed to have died at birth but the farmer recorded the birth and rearing type as a singleton. The heaviest mean birth weight was associated with lambs born and subsequently reared as singles (5.47 kg); the lightest mean birth weight was associated with lambs born and reared as triplets (4.10 kg). The association between birth-rearing type and 40-day weight differed by dam parity (P < 0.001). Lambs reared by first parity dams as singles, irrespective of birth type were, on average, heavier at 40-day weighing than lambs reared as multiples, but as parity number increased, single-born lambs reared as twins outperformed triplet-born lambs reared as singles. Irrespective of the trait evaluated, the correlation between sire EBV estimated from the accurately recorded data and sire EBV estimated from the data with recording errors was strong ranging from 0.93 (birth weight) to 0.97 (ADG). The EBV for sires with progeny data manipulated were 0.14 kg, 0.34 kg and 5.56 g/d less for birth weight, 40-day weight and ADG, respectively, compared to their equivalent EBV calculated using accurately recorded data. Results from this study highlight the importance of precise recording of birth-rearing type by producers for the generation of accurate genetic evaluations.

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