scholarly journals The size and endocrine activity of the pituitary in mice selected for large or small body-size

1962 ◽  
Vol 3 (3) ◽  
pp. 428-443 ◽  
Author(s):  
R. G. Edwards
Keyword(s):  
Body Weight ◽  
Body Size ◽  
Small Body ◽  
Large Body ◽  
Primary Response ◽  
Endocrine Activity ◽  
Body Weights ◽  
Mouse Pituitary ◽  
Highly Correlated ◽  
Thyroid Secretion

Mice of two strains, N and C, were used in studies on body-size, pituitary size, and endocrine potency of the pituitary. Strain N had been selected for large (NL) and small (NS) body-size; strain C had also been selected for large body-size (CL) but had been crossed to an outbred strain segregating pituitary dwarfism.Pituitary weights and body-weights were highly correlated, the regression lines being common in NL and NS mice. Female pituitaries were considerably heavier than male pituitaries in CL mice. In relation to body-weight, CL pituitaries were consistently heavier than those of NL or NS mice.No differences were detected in the unit potency of gonadotrophins in the pituitaries of NL and NS mice as estimated by the uterine response of immature outbred mice to subcutaneous injections of pituitary tissue. The uptake of 131I into the thyroid was comparable in NL and NS mice per unit of body-weight, and the thyroid secretion rate was also similar using animals of the same body-weight. Immature mice of both lines responded by increased growth to injections of growth hormone or fresh mouse pituitary, though the response was greater in NS than in NL mice.The primary response to selection has probably been in the size of the pituitary rather than in its unit potency. The interrelationships between body-size, body components, organ size and endocrine levels are discussed.

scholarly journals Analysis of quantitative inheritance of body size in mice: V. Effects of small numbers of polygenes on similar genetic backgrounds

1968 ◽  
Vol 11 (3) ◽  
pp. 239-246 ◽  
Author(s):  
C. K. Chai
Keyword(s):  
Body Size ◽  
Small Body ◽  
Large Body ◽  
Quantitative Inheritance ◽  
Small Body Size ◽  
Large Body Size ◽  
Genetic Interpretation ◽  
Body Weights ◽  
The Mean ◽  
The Difference

Sublines carrying isolated polygenes determining body size, developed by selection and repeated backcrossing to the LG and SM strains of mice, were inbred by full-sib matings with concomitant selection to study the inheritance of body size, using birth, weaning (28-day) and 60-day body weights as indices.Mean body weights in those sublines backcrossed to SM and selected for large body size were greater than in those selected for small body size, proving that the difference resulting from seven earlier generations of backcrossing and selection, although small, was genetic and could be fixed by inbreeding. The mean body weights of the sublines selected for small body size drifted upward despite downward selection, a phenomenon thought to be due to the pressure of natural selection outweighing that of artificial selection.In the sublines developed from backcrosses to the LG strain, mice from lines selected for small body size attained a mean body weight greater than that of mice from lines selected for large body size and also than of the parental LG strain. These results were contrary to expectation and a genetic interpretation was offered.

scholarly journals Independent evolution towards larger body size in the distinctive Faroe Island mice

2021 ◽  
Author(s):  
Ricardo Wilches ◽  
William H Beluch ◽  
Ellen McConnell ◽  
Diethard Tautz ◽  
Yingguang Frank Chan
Keyword(s):  
Body Size ◽  
Meta Analysis ◽  
Small Body ◽  
Laboratory Mouse ◽  
Large Body ◽  
Natural Populations ◽  
Size Variation ◽  
Phenotypic Traits ◽  
Island Population ◽  
Multiple Loci

Abstract Most phenotypic traits in nature involve the collective action of many genes. Traits that evolve repeatedly are particularly useful for understanding how selection may act on changing trait values. In mice, large body size has evolved repeatedly on islands and under artificial selection in the laboratory. Identifying the loci and genes involved in this process may shed light on the evolution of complex, polygenic traits. Here, we have mapped the genetic basis of body size variation by making a genetic cross between mice from the Faroe Islands, which are among the largest and most distinctive natural populations of mice in the world, and a laboratory mouse strain selected for small body size, SM/J. Using this F2 intercross of 841 animals, we have identified 111 loci controlling various aspects of body size, weight and growth hormone levels. By comparing against other studies, including the use of a joint meta-analysis, we found that the loci involved in the evolution of large size in the Faroese mice were largely independent from those of a different island population or other laboratory strains. We hypothesize that colonization bottleneck, historical hybridization, or the redundancy between multiple loci have resulted in the Faroese mice achieving an outwardly similar phenotype through a distinct evolutionary path.

scholarly journals Genetic testing of dogs predicts problem behaviors in clinical and nonclinical samples

2020 ◽  
Author(s):  
Isain Zapata ◽  
M. Leanne Lilly ◽  
Meghan E. Herron ◽  
James A. Serpell ◽  
Carlos E. Alvarez
Keyword(s):  
Body Size ◽  
Problem Behaviors ◽  
Small Body ◽  
Community Sample ◽  
Large Body ◽  
Second Phase ◽  
Logistic Regression Models ◽  
Individual Level ◽  
Increased Risk ◽  
Phenotype Data

AbstractVery little is known about the etiology of personality and psychiatric disorders. Because the core neurobiology of many such traits is evolutionarily conserved, dogs present a powerful model. We previously reported genome scans of breed averages of ten traits related to fear, anxiety, aggression and social behavior in multiple cohorts of pedigree dogs. As a second phase of that discovery, here we tested the ability of markers at 13 of those loci to predict canine behavior in a community sample of 397 pedigree and mixed-breed dogs with individual-level genotype and phenotype data. We found support for all markers and loci. By including 122 dogs with veterinary behavioral diagnoses in our cohort, we were able to identify eight loci associated with those diagnoses. Logistic regression models showed subsets of those loci could predict behavioral diagnoses. We corroborated our previous findings that small body size is associated with many problem behaviors and large body size is associated with increased trainability. Children in the home were associated with anxiety traits; illness and other animals in the home with coprophagia; working-dog status with increased energy and separation-related problems; and competitive dogs with increased aggression directed at familiar dogs, but reduced fear directed at humans and unfamiliar dogs. Compared to other dogs, Pit Bull-type dogs were not defined by a set of our markers and were not more aggressive; but they were strongly associated with pulling on the leash. Using severity-threshold models, Pit Bull-type dogs showed reduced risk of owner-directed aggression (75th quantile) and increased risk of dog-directed fear (95th quantile). Our findings have broad utility, including for clinical and breeding purposes, but we caution that thorough understanding is necessary for their interpretation and use.

scholarly journals Interrelation between body weights of sire, dam and their lambs at early stage of growth

2020 ◽  
Vol 36 (2) ◽  
pp. 205-214
Author(s):  
Violeta Caro-Petrovic ◽  
Milan Petrovic ◽  
Dragana Ruzic-Muslic ◽  
Nevena Maksimovic ◽  
Irina Sycheva ◽  
...  
Keyword(s):  
Body Weight ◽  
Early Stage ◽  
Descriptive Statistics ◽  
Coefficient Of Determination ◽  
Measures Of Association ◽  
Paired Sample ◽  
Body Weights ◽  
Sample Test ◽  
Highly Correlated

Records of female lambs and their parents of the Mis sheep breed have used. All animals are approximately have weaned at 90 days of age. Descriptive statistics, paired sample test, paired differences, measures of association, correlations and regression of body weights between female lambs and their parents have done. A complementary least body weights at 30 days and weaning between dams and lambs but utmost weight at 30 days, the lambs were higher while at weaning, the dams had higher weight. It can observe that the averages on body weights the rams were the highest, followed by lambs and the lowest the dams? body weights. The coefficient of determination of R2 varies from low to high, indicating that the lamb's body weight has more influenced by other factors that we have not considered. There were significant correlations between lamb body weight at birth and sire/dam body weight at birth. The results showed highly significant correlations of lamb's body weight at 30 days with dams but with sires, positive and very low. There had positive but no significant correlation between lamb body weight at weaning and sire body weight at weaning. Lamb body weight at weaning and dam body weight at weaning are highly correlated.

Alternative Reproductive Tactics

2020 ◽  
pp. 429-446
Author(s):  
Shawn Garner ◽  
Bryan Neff
Keyword(s):  
Body Size ◽  
Small Body ◽  
Large Body ◽  
Morphological Differentiation ◽  
Alternative Reproductive Tactics ◽  
Reproductive Tactics ◽  
Aggressive Interactions ◽  
Single Sex ◽  
Female Mimicry ◽  
Mating Opportunities

Alternative reproductive tactics (ARTs) describe variation among individuals of a single sex in the tactics used to obtain mating opportunities. In crustaceans, ARTs have been observed in multiple taxa and take a variety of forms. ARTs are most commonly observed in males and are generally associated with intense competition among males to monopolize access to breeding females. ARTs frequently involve a guard tactic that competes with other males to monopolize access to females, while a second usurper tactic foregos competition with other males and instead obtains mating opportunities through sneaking behavior. Guard and usurper tactics may be expressed conditionally based on a male’s ability to guard a female (e.g. his body size, the abundance of competitors), or may be expressed as discrete phenotypes that can also include morphological differentiation. For example, in Jassa amphipods the guard tactic is associated with large body size and an enlarged “thumb” on the claw that is used in aggressive interactions with other males, while the usurper tactic is associated with small body size and a reduced thumb. The usurper tactic can take two forms in a marine isopod: small males (gamma) use sneaking behavior to avoid competition with large males (alpha), whereas intermediate-sized males (beta) use female mimicry to avoid competition. Overall, ARTs are well-represented in crustaceans, with many opportunities for continued study to better characterize these unique adaptations.

Description of two new species from Venezuela in the highly diverse dipsadine genus Atractus (Serpentes: Colubridae)

2009 ◽  
Vol 30 (2) ◽  
pp. 233-243 ◽  
Author(s):  
Gilson Rivas Fuenmayor ◽  
Paulo Passos ◽  
Cesar Barrio-Amorós
Keyword(s):  
New Species ◽  
Body Size ◽  
Small Body ◽  
Large Body ◽  
Species Description ◽  
Small Body Size ◽  
Single Female ◽  
Large Body Size ◽  
Body Diameter ◽  
Two New Species

AbstractTwo new species of Atractus are described from Venezuela uplands and highlands on two northern Andean cordilleras. Atractus acheronius, known only from Sierra de Perijá, can be distinguished from congeners by having 17 dorsal scale rows, presence of preocular scales, seven upper and lower labials, seven maxillary teeth, 166 ventrals in the single female, 23 subcaudals, dorsum brown with small dark brown dots, large body size, huge body diameter, and small tail size. Atractus multidentatus, known only from north versant of the Cordillera de Mérida, can be distinguished from congeners by having 17 dorsal scale rows, eight upper and lower labials, 18 maxillary teeth, 153 ventrals in the single female, nine subcaudals, dorsum reddish brown with five longitudinal dark brown stripes, small body size, small body diameter, and small tail size. Additionally, a discussion concerning the species description of Atractus based on unique specimens is provided.

Avian Egg Morphometrics - Allometric Models of Egg Volume, Clutch Volume and Shape

1994 ◽  
Vol 42 (3) ◽  
pp. 307 ◽  
Author(s):  
PD Olsen ◽  
RB Cunningham ◽  
CF Donnelly
Keyword(s):  
Body Weight ◽  
Body Size ◽  
Sexual Dimorphism ◽  
Clutch Size ◽  
Egg Volume ◽  
Simple Power ◽  
Wide Range ◽  
Body Weights ◽  
Body Sizes ◽  
Simple Power Function

This paper describes three comprehensive new models of the allometric relationships between egg volume, clutch volume and shape, and body weight. Mean egg dimensions, clutch sizes and adult body weights were obtained for 326 species, mainly of four bird types: raptors (including owls), shorebirds, frogmouths (including nightjars), and storks (including the New World vultures). These are groups in which there is a wide range of body sizes and of sexual dimorphism in body size (in direction and degree). Female body weight alone accounted for 92% of the variation in egg volume. Sexual dimorphism in body size, phylogenetic relationship, and clutch size were significant contributors to the model of egg volume; their addition increased the explained variance to over 98%. The model was curvilinear (quadratic) in form, rather than linear as assumed in previous models. Larger species laid smaller eggs than expected under a simple power function. For the fitted model, within bird types, generic groupings had parallel curvilinear slopes but differing intercepts. Between bird types, the slopes differed. Clutch volume was scaled to body weight; all the bird types had a common slope, which was curvilinear. Body weight and dimorphism accounted for 89.5% of the variation in clutch volume. For all bird types, eggs became proportionally longer in shape as body weight increased, according to a simple power law. The relevance of these relationships to hypotheses on the evolution and adaptive significance of sexual dimorphism and to the trade-off between egg size and clutch size is discussed briefly.

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.

A new species of Sitana (Squamata: Agamidae) from the Deccan Peninsula Biogeographic Zone of India

Zootaxa ◽  
2021 ◽  
Vol 4948 (2) ◽  
pp. 261-274
Author(s):  
V. DEEPAK ◽  
FRANK TILLACK ◽  
NILADRI B. KAR ◽  
VIVEK SARKAR ◽  
PRATYUSH. P. MOHAPATRA
Keyword(s):  
New Species ◽  
Body Size ◽  
Small Body ◽  
Large Body ◽  
Morphological Characters ◽  
Adult Males ◽  
Blue Line ◽  
Dark Blue ◽  
A New Species ◽  
Bright Blue

We describe a new species of fan-throated lizard of the genus Sitana from the Deccan peninsula of India. The new species is from the Sitana sivalensis clade and can be readily diagnosed morphologically from S. sivalensis, S. fusca and S. schleichi by having the dewlap extending beyond forearm insertion. The new species differs from all other congeners in the combination of morphological characters such as a feebly serrated dewlap with a dark blue line on the throat in adult males (versus  a well serrated dewlap with a bright blue patch and orange spots in S. ponticeriana complex), small body size (versus a large body size in S. gokakensis and S. thondalu) and a relatively smaller dewlap size (relatively larger in S. laticeps, S. spinaecephalus, S. dharwarensis, S. gokakensis, S. thondalu, S. marudhamneydhal, S. ponticeriana and S. visiri). The new species was found to be commonly distributed in arid and open habitats as well as in farmlands and plantations in northern Andhra Pradesh, eastern Madhya Pradesh and most parts of Chhattisgarh and Odisha states. 

scholarly journals Effects of selection for independent changes in two highly correlated body weight traits of mice

1977 ◽  
Vol 29 (2) ◽  
pp. 133-145 ◽  
Author(s):  
J. C. McCarthy ◽  
D. P. Doolittle
Keyword(s):  
Body Weight ◽  
Response Selection ◽  
The Other ◽  
Index Selection ◽  
Correlated Responses ◽  
Body Weights ◽  
Independent Culling ◽  
Selection For ◽  
Highly Correlated

SUMMARYMice were selected for high and low body weight at 5 and at 10 weeks of age. Selection was performed (1) separately for each trait, and (2) for various combinations of the two traits, using (a) independent culling levels and (b) restricted indices. Two-way selection for each trait separately gave large responses and correlated responses. Selection by independent culling levels intended to increase 5-week weight while restricting change in 10-week weight gave no demonstrable response; selection by culling levels intended to decrease 5-week weight while restricting change in 10-week weight resulted in decreases in body weights at both ages. Index selection, intended to change weight at one age while holding that at the other age constant, was generally successful. Observed responses did not conform very well with predicted responses for either index or culling levels selection. The significance of these observations in regard to the problem of selection involving restriction of traits is discussed.

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