scholarly journals Correlated responses to selection for large body size in oMt1a-oGH transgenic mice: organ traits

2000 ◽  
Vol 23 (4) ◽  
pp. 771-780 ◽  
Author(s):  
K.R. Parks ◽  
E.J. Eisen ◽  
J.D. Murray
Keyword(s):  
Drinking Water ◽  
Body Weight ◽  
Genetic Correlations ◽  
Large Body ◽  
High Growth ◽  
Correlated Responses ◽  
Large Body Size ◽  
Organ Weights ◽  
Growth Increase ◽  
Selection For

The objective of the present study was to compare correlated responses in liver, spleen, kidney, heart and testis absolute weights and as a percentage of 8-week body weight following selection for large 8-week body weight in twice-replicated nontransgenic and transgene-carrier lines of mice from two genetic backgrounds. The transgene was an ovine metallothionein 1a-ovine growth hormone (oMt1a-oGH) construct, which was activated by adding 25 mM ZnSO4 to the drinking water. Lines NM and NC were nontransgenic lines derived from a high-growth and randomly selected background, respectively. Lines TM and TC were transgene-carrier lines formed from the respective genetic backgrounds. Line CC was a nontransgenic control from the randomly selected background. At weaning, male mice from each line were assigned to either zinc supplemented or control drinking water. Toe-clips were assayed by PCR for the presence or absence of the transgene. Correlated responses of absolute weights of all organs in nontransgenic lines indicated moderately high genetic correlations of organ weights with body weight, but on a percentage of body weight basis, the correlated responses were much lower. The correlated responses in visceral organ weights were lower in the presence of the inactivated oMt1a-oGH transgene than in its absence. The presence of the activated oMt1a-oGH combined with the effects of selection for growth increase had a greater impact on increasing the size of the splanchnic organs than did selection for large body weight in the absence of the transgene.

Response to selection in Australian Merino sheep. III. Single character selection for high and low values of wool weight and its components

1970 ◽  
Vol 21 (6) ◽  
pp. 955 ◽  
Author(s):  
HN Turner ◽  
MG Brooker ◽  
CHS Dolling
Keyword(s):  
Body Weight ◽  
Unit Area ◽  
Genetic Correlations ◽  
Fibre Diameter ◽  
Initial Response ◽  
Skin Area ◽  
Correlated Responses ◽  
Fibre Number ◽  
Selection For ◽  
Staple Length

Direct and correlated responses are reported for 10 traits in eight pairs of lines under selection for high and low values of single characteristics : clean wool weight per head, clean wool weight per unit skin area (measured only in the groups under selection for it), body weight, wrinkle score, fibre number per unit skin area (adjusted for body weight), fibre diameter, staple length, and percentage clean yield. All groups showed overall divergence in the character under selection, though response was not always symmetrical, and in two cases (long staple and low fibre number) there was no continuing response after the initial response to extreme selection of the base parents. In all except one case, whenever previous estimates of genetic correlation were at the level of 0.2 or higher, correlated responses were in the predicted direction, though not always symmetrical in magnitude. The exception was a previously reported negative correlation between fibre number and staple length, which was not exhibited under selection for either character. Where two characters of a pair were under selection, reciprocal responses agreed in sign; magnitude will be examined in a later paper. Wool per unit area was shown to have a greater influence on clean wool weight than that of surface area, with staple length on this occasion being the most important component of wool per unit area. Reasons for an apparent decrease in the relative importance of fibre number are discussed. Three other points of importance in sheep breeding are again emphasized by these results : 1. Crimp in several pairs of groups was a poor indicator of fibre diameter. 2. Increases in clean wool weight were associated with falls in crimp number, even though fibre diameter actually became finer; diameter, not crimp, should therefore be used as a guide to wool quality. 3. The absence of genetic correlations DL and NL indicates that selection can be for high N (fibre number) with high L (staple length) and low D (fibre diameter) -in other words, a desirable fleece -with no impeding genetic correlations.

scholarly journals Correlated responses to selection for large body size in oMt1a-oGH transgenic mice: reproductive traits

2000 ◽  
Vol 75 (2) ◽  
pp. 199-208 ◽  
Author(s):  
K. R. PARKS ◽  
E. J. EISEN ◽  
I. J. PARKER ◽  
L. G. HESTER ◽  
J. D. MURRAY
Keyword(s):  
Body Weight ◽  
Transgenic Mice ◽  
Reproductive Performance ◽  
Large Body ◽  
Low Frequency ◽  
High Growth ◽  
Reproductive Traits ◽  
Correlated Responses ◽  
Term Selection ◽  
Transgenic Lines

Correlated responses in female reproductive performance were evaluated following short-term selection within full-sib families for increased 8-week body weight in two replicates of four lines of mice: two ovine metallothionein–ovine growth hormone (oMt1a-oGH) transgene-carrier lines, one from a high-growth background (TM) and one from a control background (TC), and two non-transgenic lines, one from each of these genetic backgrounds (NM and NC, respectively). A fifth line (CC), not containing the transgene, served as a randomly selected control. The initial frequency of the oMt1a-oGH transgene construct in the TM and TC lines was 0·5. The frequency of transgenic females sampled at generations 7 and 8 of selection was 84·0% and 6·1% in the TC and TM lines, respectively. No significant female infertility differences were detected between transgene-carrier and non-transgenic lines or between transgenic and non-transgenic mice within carrier lines, whereas high-growth background lines had a higher infertility than control background lines (P < 0·05). Correlated responses in the TC transgene-carrier line were suggestive of reduced reproductive performance as indicated by increased post-implantation mortality (P < 0·05), number of dead fetuses plus implants (P < 0·05), and loss of fetuses from day 16 to parturition (P < 0·001). For the first two traits, the negative correlated responses were accounted for by the reduced performance of transgenic compared with non-transgenic females. Embryos carrying the transgene may also have a lower viability. In contrast, the NC non-transgenic line did not exhibit reduced reproductive performance for these traits. The low frequency of the transgene in the high-growth background TM line was associated with reduced fitness and a lower additive effect for 8-week body weight compared with the control background TC line.

Predicted and realized responses to selection for an index of bone length and body weight in Scottish Blackface sheep 2. Correlated responses in lifetime productivity

1986 ◽  
Vol 43 (3) ◽  
pp. 437-445 ◽  
Author(s):  
K. D. Atkins ◽  
R. Thompson
Keyword(s):  
Body Weight ◽  
Population Genetic ◽  
Genetic Correlations ◽  
Reproduction Rate ◽  
Base Population ◽  
Correlated Responses ◽  
Genetic Response ◽  
Bone Length ◽  
Body Weights ◽  
Selection For

ABSTRACTA selection experiment with Scottish Blackface sheep was used to compare predicted and realized correlated responses to selection. Three lines were maintained between 1956 and 1974 in which selection was either at random or for high and low values of an index of cannon-bone length at 8 weeks of age adjusted for body weight at the same age.There was no evidence of asymmetrical responses in any trait. Selection for increased cannon-bone length, adjusted for body weight, resulted in (i) increased body weights at all ages between birth and maturity, (ii) increased reproduction rate, principally from increased litter size but also from small responses in ewe fertility and lamb survival and (iii) decreased survival of adult ewes. The realized genetic correlations were relatively small (up to 0·3) but mostly significantly different from zero, whereas base population genetic correlation estimates were very imprecise. The realized responses in reproduction rate were probably a consequence of the genetic response in body weight.

Genetic and phenotypic relationships between fertility and wool production in 2-year-old Merino sheep

1967 ◽  
Vol 18 (3) ◽  
pp. 515 ◽  
Author(s):  
JP Kennedy
Keyword(s):  
Body Weight ◽  
Genetic Correlations ◽  
Standard Errors ◽  
Phenotypic Correlation ◽  
Correlated Responses ◽  
Merino Sheep ◽  
Wool Production ◽  
Phenotypic Correlations ◽  
Selection For ◽  
Fertility Traits

Records of the lambing and weaning performance (fertility) of 2-year-old Peppin Merino ewes were analysed. Repeatability and heritability of number of lambs born and weaned were low. Heritability of number of lambs born was significantly different from zero (0.20 ± 0.10). Phenotypic and genetic correlations between the fertility traits and greasy wool weight, all measured at approximately 15 months of age, were calculated. Phenotypic correlations between number of lambs born or weaned and greasy wool weight were negative and significant. The phenotypic correlation between number of lambs weaned and clean wool weight was negative and significant. Significant negative genetic correlations were found between number of lambs born and both greasy wool weight and clean wool weight. Genetic correlations between number of lambs weaned and the fleece and body traits had very large standard errors. The results were used to estimate correlated responses in fertility resulting from selection for greasy wool weight, clean wool weight, and body weight of –0.08i, –0.13i, and 0.03i respectively.

Genetic Parameters of Body Weights in Hill Sheep

1984 ◽  
Vol 1984 ◽  
pp. 45-45 ◽  
Author(s):  
K.D. Atkins
Keyword(s):  
Body Weight ◽  
Genetic Parameters ◽  
Genetic Correlations ◽  
Body Growth ◽  
Optimal Time ◽  
Correlated Responses ◽  
Body Weights ◽  
Selection For

There are few published studies on the genetics of body growth to maturity in sheep. Such information is required for choosing an optimal time of selection for body weight and to predict correlated responses to selection at all stages of an animal's lifetime. The data were derived from a randomly selected control flock of Scottish Blackface sheep on a hard heather hill research farm in Peeblesshire, Scotland. The objectives of the analysis were to estimate the heritability of body weight at various ages between birth and maturity, and the genetic correlations between these weights.

scholarly journals Atmospheric Hypoxia Limits Selection for Large Body Size in Insects

PLoS ONE ◽  
2009 ◽  
Vol 4 (1) ◽  
pp. e3876 ◽  
Author(s):  
C. Jaco Klok ◽  
Jon F. Harrison
Keyword(s):  
Body Size ◽  
Large Body ◽  
Large Body Size ◽  
Selection For

scholarly journals PSVIII-38 Late-Breaking Abstract: Estimating genetic parameters of feed efficiency traits in American mink

2020 ◽  
Vol 98 (Supplement_4) ◽  
pp. 347-347
Author(s):  
Pourya Davoudi ◽  
Duy Ngoc Do ◽  
Guoyu Hu ◽  
Siavash Salek Ardestani ◽  
Younes Miar
Keyword(s):  
Body Weight ◽  
Genetic Correlation ◽  
Feed Intake ◽  
Feed Efficiency ◽  
Fixed Effects ◽  
Genetic Parameters ◽  
American Mink ◽  
Genetic Correlations ◽  
Final Body Weight ◽  
Selection For

Abstract Feed cost is the major input cost in the mink industry and thus improvement of feed efficiency through selection for high feed efficient mink is necessary for the mink farmers. The objective of this study was to estimate the heritability, phenotypic and genetic correlations for different feed efficiency measures, including final body weight (FBW), daily feed intake (DFI), average daily gain (ADG), feed conversion ratio (FCR) and residual feed intake (RFI). For this purpose, 1,088 American mink from the Canadian Center for Fur Animal Research at Dalhousie Faculty of Agriculture were recorded for daily feed intake and body weight from August 1 to November 14 in 2018 and 2019. The univariate models were used to test the significance of sex, birth year and color as fixed effects, and dam as a random effect. Genetic parameters were estimated via bivariate models using ASReml-R version 4. Estimates of heritabilities (±SE) were 0.41±0.10, 0.37±0.11, 0.33±0.14, 0.24±0.09 and 0.22±0.09 for FBW, DFI, ADG, FCR and RFI, respectively. The genetic correlation (±SE) was moderate to high between FCR and RFI (0.68±0.15) and between FCR and ADG (-0.86±0.06). In addition, RFI had low non-significant (P &gt; 0.05) genetic correlations with ADG (0.04 ± 0.26) and BW (0.16 ± 0.24) but significant (P &lt; 0.05) high genetic correlation with DFI (0.74 ± 0.11) indicating that selection for lower RFI will reduce feed intake without adverse effects on the animal size and growth rate. The results suggested that RFI can be implemented in genetic/genomic selection programs to reduce feed intake in the mink production system.

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.

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