scholarly journals The effect of replicated selection for body weight in mice on vertebral shape

1988 ◽  
Vol 51 (2) ◽  
pp. 129-135 ◽  
Author(s):  
D. R. Johnson ◽  
P. O'Higgins ◽  
T. J. McAndrew
Keyword(s):  
Body Weight ◽  
Body Size ◽  
Fourier Analysis ◽  
Shape Change ◽  
Small Body ◽  
Small Body Size ◽  
Selection For ◽  
Main Component ◽  
Vertebral Shape ◽  
And Control

SummaryThe shapes of T1 and T2 vertebrae from unselected Q strain mice and from strains selected for large and small body size were studied by Fourier analysis in order to ascertain whether shape change was produced by size selection. The vertebrae of large, small and control strains were easily distinguishable, but between replicate groups shape differences were less marked. The main component of shape change was size related, but mice unselected for size also showed a non-size-related shape change.

scholarly journals Selection for small body size favours contrasting sex-specific life histories, boldness and feeding in medaka, Oryzias latipes

2019 ◽  
Vol 19 (1) ◽  
Author(s):  
Beatriz Diaz Pauli ◽  
Sarah Garric ◽  
Charlotte Evangelista ◽  
L. Asbjørn Vøllestad ◽  
Eric Edeline
Keyword(s):  
Body Size ◽  
Life Histories ◽  
Small Body ◽  
Oryzias Latipes ◽  
Small Body Size ◽  
Selection For

scholarly journals The fertility of mice selected for large or small body size

1960 ◽  
Vol 1 (3) ◽  
pp. 393-407 ◽  
Author(s):  
Ruth E. Fowler ◽  
R. G. Edwards
Keyword(s):  
Body Weight ◽  
Body Size ◽  
Small Body ◽  
Follicle Stimulating Hormone ◽  
Weight Ratio ◽  
Total Body Weight ◽  
Control Line ◽  
Small Body Size ◽  
Natural Mating ◽  
Stimulating Hormone

The fertility of two unrelated strains of mice (strains N and C) which had both been selected for large and small body size has been studied.The fertility of pairs of mice in the large or small lines of strain C was unimpaired by selection. In strain N, some of the pairs in the large and small lines, but not in the control line, were sterile. Sterility in the large line was due to the low libido of the males, and not to female infertility. Sterility in the small line was probably due to hypo-functioning of the anterior pituitary of some females: the oestrous cycle was delayed or absent, some mice failed to ovulate after mating, and a high proportion of those mating had no implanted embryos at 12 days' gestation. Oestrus and ovulation could be induced in mice of the small line of strain N by exogenous gonadotrophins, and the proportion of mice with implanted embryos was considerably increased by progesterone supplements.The number of eggs found after natural mating was considerably higher in large mice than in small mice, and was significantly correlated with body weight in the small line of strain C only. The egg-number/body-weight ratio was higher in the lines of strain C than in those of strain N, though the ratios were similar when carcass fat was subtracted from total body weight.The amount of endogenous follicle-stimulating hormone secreted by the mice of the five lines was estimated by inducing ovulation with various amounts of exogenous gonadotrophins, and comparing the number of eggs found after each dose with the mean number ovulated after natural mating. Estimates of the amount of follicle-stimulating hormone secreted by mice of strain C were higher than those for mice of strain N.Differences in the rates of growth and in the numbers of eggs ovulated after natural mating indicate a higher level of pituitary activity in strain C than in strain N.

The growth and carcass composition of strains of mice selected for large and small body size

1958 ◽  
Vol 51 (2) ◽  
pp. 137-148 ◽  
Author(s):  
Ruth E. Fowler
Keyword(s):  
Body Weight ◽  
Body Size ◽  
Small Body ◽  
Carcass Composition ◽  
Small Body Size ◽  
Body Protein ◽  
Percentage Composition ◽  
Growing Period ◽  
Constant Rate ◽  
Rates Of Growth

The growth and carcass composition of two strains of mice (N- and C-strain), which had both been selected for large and small body size by Falconer, have been studied.Differences in body weight between mice of the N-strain and their controls were apparent at birth and were fully maintained up to 30 weeks of age. The patterns of growth were similar in all three lines, although the large line grew at a faster rate than the small line, the controls being intermediate. Differences in absolute and relative rates of growth between the three lines reach a maximum from 21 to 35 days of age and declined thereafter.Growth in the large line of the N-strain from 14 to 40 days of age was largely due to an increase in body protein and water; after this age, increase in weight was caused mainly by fat deposition. In the small line of this strain, protein, water and fat were deposited at a more constant rate during the whole growing period. Differences in rates of growth may account for the differences in the percentage composition found between mice of the large and small lines of the N-strain at the same age.

Number of fibres in the skeletal muscle of miniature pigs

1978 ◽  
Vol 91 (1) ◽  
pp. 255-256 ◽  
Author(s):  
N. C. Stickland ◽  
G. Goldspink
Keyword(s):  
Skeletal Muscle ◽  
Body Weight ◽  
Small Body ◽  
Domestic Animals ◽  
The Body ◽  
Muscle Fibres ◽  
Miniature Pig ◽  
Small Body Size ◽  
Miniature Pigs ◽  
Selection For

There is evidence that selection for small body size in mice results in a decrease in the total number of muscle fibres in a given muscle (Luff & Goldspink, 1967; Hanrahan, Hooper & McCarthy, 1973). It has also been shown that small chickens have fewer muscle fibres in certain muscles than larger chickens (Smith, 1963). This type of work has not, however, been extended to a study of the larger domestic animals. At Göttingen in Germany, Haring et al. (1966) have developed a breed of miniature pig which, at 6 months of age, was about a third of the body weight of commercial pigs. We therefore decided to investigate the muscles of these miniature pigs and compare them with commercial pig muscles, paying particular attention to the number of muscle fibres.

scholarly journals Adaptive significance of small body size under poor socio-economic conditions in southern Peru

1973 ◽  
Vol 39 (2) ◽  
pp. 255-261 ◽  
Author(s):  
A. Roberto Frisancho ◽  
Jorge Sanchez ◽  
Danilo Pallardel ◽  
Lizandro Yanez
Keyword(s):  
Body Size ◽  
Small Body ◽  
Adaptive Significance ◽  
Economic Conditions ◽  
Small Body Size ◽  
Southern Peru
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