scholarly journals SELECTION FOR BODY WEIGHT IN THE MOUSE AT THREE TEMPERATURES AND THE CORRELATED RESPONSE IN TAIL LENGTH

Genetics ◽  
1970 ◽  
Vol 65 (3) ◽  
pp. 505-523
Author(s):  
R L Baker ◽  
F R M Cockrem
Keyword(s):  
Body Weight ◽  
Tail Length ◽  
Correlated Response ◽  
Selection For

CORRELATED RESPONSES IN EGG QUALITY TRAITS TO SELECTION FOR EARLY BODY WEIGHT IN MEAT-TYPE CHICKENS

1972 ◽  
Vol 14 (3) ◽  
pp. 477-482 ◽  
Author(s):  
V. Buvanendran ◽  
E. S. Merritt
Keyword(s):  
Body Weight ◽  
Egg Quality ◽  
Correlated Response ◽  
Quality Traits ◽  
Correlated Responses ◽  
Egg Weight ◽  
Shell Color ◽  
Blood Spots ◽  
Selection For ◽  
Meat Type

The correlated responses in egg quality traits to selection for high early body weight were studied in seven meat-type populations comprising five selected and two control lines. Traits studied were specific gravity, egg weight, albumen height, Haugh units, shell color, egg shape, shell roughness, wrinkling and asymmetry, and incidence of blood spots, meat spots and double yolks. Significant (P < 0.05 or < 0.01) correlated changes, as determined by the regression of correlated response (egg quality traits) on primary response (body weight), were obtained for egg weight, albumen height, Haugh units, asymmetry of shell and blood spots. All but blood spots increased with selection for high body weight. Shell color showed a consistent trend towards a darker color with increasing body weight. Scores for roughness of shell and, with one minor exception, the incidence of double yolks, also showed consistent trends (positive) with increasing body weight. Estimates of genetic correlations, derived directly from intra-line genetic analyses of the six pedigreed populations in the experiment, were in most cases in reasonable agreement with realized estimates.

scholarly journals EFFECT OF SELECTION ON HERITABILITY AND GENETIC CORRELATION OF TWO QUANTITATIVE TRAITS IN MICE

1974 ◽  
Vol 16 (3) ◽  
pp. 599-609 ◽  
Author(s):  
T. K. Cheung ◽  
R. J. Parker
Keyword(s):  
Body Weight ◽  
Genetic Correlation ◽  
Quantitative Traits ◽  
Random Mating ◽  
Tail Length ◽  
Control Group ◽  
Mass Selection ◽  
Initial Population ◽  
Significant Difference ◽  
Selection For

The effects of different intensities of single trait directional selection on the heritability and genetic correlation of two quantitative traits in random mating populations of mice were observed during 14 generations. The initial population was divided at random into five groups (A, B, C, D and E). Group A and Group B were under 30% and 60% mass selection for large 6-week body weight, respectively. Group C and Group D were under 30% and 60% mass selection for long 6-week tail length, respectively. Group E acted as control group with no selection applied. In all groups, the parent population consisted of 15 males and 30 females each generation, mated at random.Direct selection had no apparent effect on the heritability of either the trait under selection or the correlated trait over the 14 generations. Heritability of 6-wk tail length was higher than the heritability of 6-wk body weight. Estimates of heritability of 6-wk tail length ranged from 0.15 ± 0.22 to 0.68 ± 0.24, while estimates of heritability of 6-wk body weight ranged from 0.05 ± 0.17 to 0.33 ± 0.09. There was no significant difference among the estimates of genetic correlation between the two traits in the five selection groups. Estimates of realized genetic correlation between 6-wk body weight and 6-wk tail length seemed to indicate that more intense selection led to some decrease in genetic correlation between the two traits.

scholarly journals Effect of disruptive selection for body conformation on age variations of femoral morphometrie traits, in mice

1999 ◽  
Vol 42 (2) ◽  
pp. 201-210
Author(s):  
L. Hinrichsen ◽  
D. Mana ◽  
R. Di Masso ◽  
M. T. Font
Keyword(s):  
Body Weight ◽  
Tail Length ◽  
Whole Body ◽  
Disruptive Selection ◽  
Phenotypic Correlation ◽  
Control Line ◽  
Genetic Determination ◽  
Body Conformation ◽  
Age Variations ◽  
Selection For

Abstract. The effect of disruptive selection for body conformation on body weight and length, tail length, and femur weight and length at different stages of development (21, 42, 63, and 120 days of age) was analysed in four mouse lines of the CBi stock selected for (CBi+, CBi-) and against (CBi/L, CBi/C) the phenotypic correlation between body weight and tail length, and die unselected control line CBi. As expected, body weight and tail length distributed according to the selection criteria; rrunk length (whole body length minus tail length) behaved as body welght at all ages. CBi/L had the highest femoral length (p < 0.01), and CBi/C attained the highest femoral weight (p < 0.01). CBi+ and CBi-, harmonically large or small, differed between them and from the control line in both variables (p < 0.001). These findings further corroborate the proposal that bone mass is markedly affected by the skeleton function as support of soft tissues. The allometric analysis ofthe regression of femur weight on femur length suggests that, in this model, a) the demand posed by the selective pressure forced each genotype to find a unique Solution, b) this response is sex-dependent, and c) genetic determination ofthe parameters involved in this allometric relationship is, at least, partially independent.

Effects of divergent selection for body weight on fibre number and diameter in two mouse muscles

1973 ◽  
Vol 16 (1) ◽  
pp. 7-16 ◽  
Author(s):  
J. P. Hanrahan ◽  
A. C. Hooper ◽  
J. C. McCarthy
Keyword(s):  
Body Weight ◽  
Fibre Diameter ◽  
Correlated Response ◽  
Weight Changes ◽  
Body Weight Changes ◽  
Muscle Weight ◽  
Phenotypic Correlations ◽  
Fibre Number ◽  
Selection For ◽  
Anterior Tibialis

SUMMARYThe effects of selection for increased or decreased body weight in mice, at 5 or 10 weeks of age, on the fibre number, fibre diameter and weight of the m. sternomastoideus and m. anterior tibialis muscles were studied. Unselected control mice were also included. Significant effects were detected in the case of each of the traits. However, the magnitude of any particular correlated response to selection varied between muscles and between selection ages in an unsystematic fashion. Most of the changes in muscle weight resulting from selection were attributable to positively correlated changes in fibre number but they were also accompanied by changes in fibre diameter in some cases.The correlated responses described indicate the difficulty of predicting how selection for body weight changes will influence cellular structure of any given muscle.Phenotypic correlations between muscle fibre number and diameter were essentially zero. The phenotypic correlations between muscle weight and fibre number and fibre diameter were positive.Sex had no effect on fibre number but had an effect on fibre diameter which depended on the particular muscle and the age of the animal.

scholarly journals Uterine and Postnatal Maternal Effects in Mice Selected for Differential Rate of Early Development

Genetics ◽  
1999 ◽  
Vol 153 (2) ◽  
pp. 905-917 ◽  
Author(s):  
Brian K Rhees ◽  
Cynthia A Ernst ◽  
Christina H Miao ◽  
William R Atchley
Keyword(s):  
Postnatal Development ◽  
Maternal Effects ◽  
Tail Length ◽  
Postnatal Growth ◽  
Correlated Response ◽  
Control Line ◽  
Differential Rate ◽  
Early Postnatal Development ◽  
Specific Effects ◽  
Selection For

Abstract A series of mouse lines was produced by long-term restricted index selection for divergent rate of growth during early and late postnatal development. The selection program was based on the following treatments: E+ and E- lines were selected to alter birth to 10-day weight gain while holding late gain for both lines constant and a control line was established via random selection. Using embryo transfer and crossfostering methodology, we partitioned postnatal growth for E+, E-, and C lines into progeny genetic, uterine maternal, and nurse maternal components. Selection for differential early growth resulted in correlated response in uterine and nurse maternal effects on body weights, with significant genetic-by-environment interactions. Significant uterine effects were also observed in tail length measurements. Direct uterine effects on body weight were relatively small and resulted in growth rate differences early in development. Nurse effects were large, resulting in modification of progeny growth trajectory especially during early postnatal development. Genetic-by-uterine interactions were large and demonstrate progeny-specific effects of the prenatal uterine environment.

scholarly journals Effect of selection for development rate on reproductive onset in female mice

1999 ◽  
Vol 74 (1) ◽  
pp. 55-64 ◽  
Author(s):  
C. A. ERNST ◽  
P. D. CRENSHAW ◽  
W. R. ATCHLEY
Keyword(s):  
Growth Rate ◽  
Body Weight ◽  
Slow Growth ◽  
Body Weight Gain ◽  
Correlated Response ◽  
Balance Growth ◽  
Vaginal Opening ◽  
Reproductive Onset ◽  
Mature Weight ◽  
Selection For

This research reports analyses of correlated response in reproductive onset in ICR mice after 23 generations of restricted index selection for divergent body weight gain, early (birth–10 days) or later (28–56 days) in life. Long-term selection altered growth trajectories and 56 day body weight of individuals under different selection regimes in this study. Mice in lines under early selection have the same percentage mature weight at vaginal opening as controls (63%). Vaginal opening is delayed in mice selected for slow early growth, which take longer to reach what appears to be a weight threshold. In contrast, individuals in lines selected for later slow growth undergo vaginal opening at the same age as controls, but at a lower weight and increased percentage mature weight. Pre-compensation or ‘counter-balance growth’ is observed in these lines, with mice selected for late enhanced growth reaching 52% of mature weight at vaginal opening while mice with late slow growth attain 71% of mature weight prior to vaginal opening. Only 42% of mice with late slow growth attain first oestrus by 56 days. We speculate this is a function of growth rate and fat/lean ratio. Mice with early slow growth show compensatory growth, reaching first oestrus at a similar time to controls. We conclude that selection for growth rate has asymmetrically affected reproductive onset, with lines selected for suppressed gains experiencing delays in the reproductive onset traits measured.

CARCASS COMPOSITION OF MICE AFTER LONG-TERM SELECTION FOR LARGE SIX-WEEK BODY WEIGHT OR LONG SIX-WEEK TAIL LENGTH

1985 ◽  
Vol 65 (1) ◽  
pp. 239-242 ◽  
Author(s):  
R. I. McKAY ◽  
A. D. GRAHAM ◽  
R. J. PARKER
Keyword(s):  
Body Weight ◽  
Key Words ◽  
Tail Length ◽  
Fat Deposition ◽  
Carcass Composition ◽  
Control Line ◽  
Selected Lines ◽  
Term Selection ◽  
Selection For

Carcass analysis of mice selected for large 6-wk body weight (BW6) or long 6-wk tail length (TL6) is reported. There was no evidence of excessive fat deposition in the selected lines when compared to a randomly bred control line. Key words: Mice, carcass composition, selection, fat

Analysis of production records from a lowland sheep flock 3. Phenotypic and genetic parameters for reproductive performance

1974 ◽  
Vol 19 (1) ◽  
pp. 33-45 ◽  
Author(s):  
P. A. Forrest ◽  
Maurice Bichard
Keyword(s):  
Body Weight ◽  
Reproductive Performance ◽  
Genetic Gain ◽  
Genetic Parameters ◽  
Phenotypic Correlation ◽  
Correlated Response ◽  
Sheep Flock ◽  
Average Litter Size ◽  
Genetic Level ◽  
Selection For

SUMMARYPhenotypic and genetic parameters for reproductive performance in a flock of Clun Forest ewes have been estimated. Average litter size (ALS) appeared to be more repeatable than the number of lambs born per ewe mated and present at lambing (NLBEM), and the estimates obtained by regression (0·15 and 0·14) were slightly higher than those from the analyses of variance (0·12 and 0·09). The repeatability of barrenness was very low (0·05). It was concluded that little scope existed for the improvement of reproductive performance from a regular policy of culling.Estimates of heritability by analysis of variance and a method for all-or-none traits were 0·12 and 0·11 for ALS, and 0·15 and 0·10 for NLBEM, whereas barrenness was less heritable (0·07). An estimate of 016 was found for the heritability of ALS performance over two years. The phenotypic correlation between body weight and reproductive performance were positive yet small (ALS:+0·16; NLBEM:+0·10), while at the genetic level ALS was more strongly related to body weight (+0·21) than NLBEM (-0·04). The genetic regressions indicated that an increase of 5 lambs per 100 ewes lambing would accompany genetic gain of 5 kg in ewe body weight, while an increase of 1 lamb per ewe lambing would lead to a correlated response in body weight of 5 kg.Selection for ALS on the basis of dams' performance, within the flock studied, would be expected to yield a rate of progress of 2% per annum.

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