scholarly journals Aspects of temperature regulation in mice selected for large and small size

1984 ◽  
Vol 43 (3) ◽  
pp. 299-306 ◽  
Author(s):  
Carol Becker Lynch ◽  
R. C. Roberts
Keyword(s):  
Body Size ◽  
Food Consumption ◽  
Genetic Correlations ◽  
Natural Populations ◽  
Temperature Adaptation ◽  
Behavioural Thermoregulation ◽  
Large Size ◽  
Brown Adipose ◽  
Selection For ◽  
Specific Food

SUMMARYWe measured traits involved in physiological and behavioural thermoregulation in the 6 replicates of a selection experiment for large and small size (6-week weight) in mice, including control lines (18 lines in all). The observed genetic correlations between body size and thermoregulatory traits are consistent with a thermoregulatory advantage of large size, including decreased weight-specific food consumption and increased nest-building, with no change in body temperature. The differences in food consumption were closely paralleled by differences in amount of brown adipose tissue, strongly suggesting that much of the decreased efficiency of the small lines is due to heat production by brown fat. These results are consistent with available observations on natural populations, that selection for temperature adaptation probably has had some influence on body size in this species.

scholarly journals Heterosis among lines of mice selected for body weight: 3. Thermoregulation

1986 ◽  
Vol 48 (2) ◽  
pp. 95-100 ◽  
Author(s):  
Carol Becker Lynch ◽  
R. C. Roberts ◽  
W. G. Hill
Keyword(s):  
Adipose Tissue ◽  
Brown Adipose Tissue ◽  
Food Consumption ◽  
Diallel Cross ◽  
Nest Building ◽  
Lower Weight ◽  
Large Size ◽  
Brown Adipose ◽  
Complete Diallel Cross ◽  
Specific Food

SummaryCrosses were made among 18 lines of mice, six previously selected for large 6-week weight, six for small 6-week weight, and six unselected controls, comprising a complete diallel cross among sizes and a partial diallel cross among replicate lines within sizes, and all purebred matings. Across all groups large size was associated with lower weight-specific food consumption and brown adipose tissue, and increased nest-building. Overall the crosses had lower weight-specific food consumption, and increased nest-building, body temperature, and brown adipose tissue than the purebreds. In general, heterosis in crosses between lines of different size, especially those involving large lines, tended to exceed that in crosses between lines of the same size.

scholarly journals Further evidence for coadaptation in crosses between geographic populations of Drosophila pseudoobscura

1968 ◽  
Vol 12 (3) ◽  
pp. 317-330 ◽  
Author(s):  
Wyatt W. Anderson
Keyword(s):  
Body Size ◽  
Species Difference ◽  
Natural Populations ◽  
Drosophila Pseudoobscura ◽  
Gene Pools ◽  
The Pacific ◽  
Geographic Populations ◽  
High Heritability ◽  
Selection For ◽  
Additional Support

Body size in Drosophila pseudoobscura is a continuously varying character with a high heritability; it is almost certainly related to fitness. Natural populations of D. pseudoobscura from Canada to Mexico have been sampled and found to vary geographically in body size. The geographic variation for the genes determining size is to some extent correlated with the physiographic division of the West. The populations from the Pacific coast have genetically smaller flies than do those from the interior provinces. Experimental populations derived from the samples of seven widely separated natural populations were crossed to yield F1 and F2 hybrid generations. Body size in the F1's varied irregularly, while the F2's showed a consistent ‘breakdown’, the F2's being significantly smaller than their F1 parents. The F1's were significantly less variable than their parents, while the F2's were significantly more variable than their parents of the F1 generation. The natural populations possess coadapted genetic systems, with genes mutually adjusted by selection for favorable interactions. Recombination disrupted the balanced genic complexes to give the F2 breakdown and the increased F2 variability. D. pseudoobscura differs from D. subobscura in showing the effects expected in crosses between coadapted systems. This species difference lends additional support to the hypothesis that the gene pools of these two successful species respond in different ways to environmental variation. The gene pool of D. pseudoobscura is flexible and changes readily, while that of D. subobscura is relatively rigid.

scholarly journals Body size affects the evolution of hidden colour signals in moths

2017 ◽  
Vol 284 (1861) ◽  
pp. 20171287 ◽  
Author(s):  
Changku Kang ◽  
Reza Zahiri ◽  
Thomas N. Sherratt
Keyword(s):  
Body Size ◽  
Large Prey ◽  
Large Species ◽  
Large Size ◽  
The Family ◽  
General Mathematical Model ◽  
Selection For ◽  
Behavioural Experiments ◽  
Comparative Phylogenetic Analysis ◽  
Colour Signals

Many cryptic prey have also evolved hidden contrasting colour signals which are displayed to would-be predators. Given that these hidden contrasting signals may confer additional survival benefits to the prey by startling/intimidating predators, it is unclear why they have evolved in some species, but not in others. Here, we have conducted a comparative phylogenetic analysis of the evolution of colour traits in the family Erebidae (Lepidoptera), and found that the hidden contrasting colour signals are more likely to be found in larger species. To understand why this relationship occurs, we present a general mathematical model, demonstrating that selection for a secondary defence such as deimatic display will be stronger in large species when (i) the primary defence (crypsis) is likely to fail as its body size increases and/or (ii) the secondary defence is more effective in large prey. To test the model assumptions, we conducted behavioural experiments using a robotic moth which revealed that survivorship advantages were higher against wild birds when the moth has contrasting hindwings and large size. Collectively, our results suggest that the evolutionary association between large size and hidden contrasting signals has been driven by a combination of the need for a back-up defence and its efficacy.

scholarly journals Body size affects the evolution of eyespots in caterpillars

2015 ◽  
Vol 112 (21) ◽  
pp. 6664-6669 ◽  
Author(s):  
Thomas John Hossie ◽  
John Skelhorn ◽  
Jesse W. Breinholt ◽  
Akito Y. Kawahara ◽  
Thomas N. Sherratt
Keyword(s):  
Body Size ◽  
Large Body ◽  
Large Prey ◽  
Laboratory Setting ◽  
Large Body Size ◽  
Small Prey ◽  
Avian Predators ◽  
Predator Attack ◽  
Large Size ◽  
Selection For

Many caterpillars have conspicuous eye-like markings, called eyespots. Despite recent work demonstrating the efficacy of eyespots in deterring predator attack, a fundamental question remains: Given their protective benefits, why have eyespots not evolved in more caterpillars? Using a phylogenetically controlled analysis of hawkmoth caterpillars, we show that eyespots are associated with large body size. This relationship could arise because (i) large prey are innately conspicuous; (ii) large prey are more profitable, and thus face stronger selection to evolve such defenses; and/or (iii) eyespots are more effective on large-bodied prey. To evaluate these hypotheses, we exposed small and large caterpillar models with and without eyespots in a 2 × 2 factorial design to avian predators in the field. Overall, eyespots increased prey mortality, but the effect was particularly marked in small prey, and eyespots decreased mortality of large prey in some microhabitats. We then exposed artificial prey to naïve domestic chicks in a laboratory setting following a 2 × 3 design (small or large size × no, small, or large eyespots). Predators attacked small prey with eyespots more quickly, but were more wary of large caterpillars with large eyespots than those without eyespots or with small eyespots. Taken together, these data suggest that eyespots are effective deterrents only when both prey and eyespots are large, and that innate aversion toward eyespots is conditional. We conclude that the distribution of eyespots in nature likely results from selection against eyespots in small caterpillars and selection for eyespots in large caterpillars (at least in some microhabitats).

scholarly journals Ant collective behavior is heritable and shaped by selection

2019 ◽  
Author(s):  
Justin T. Walsh ◽  
Simon Garnier ◽  
Timothy A. Linksvayer
Keyword(s):  
Body Size ◽  
Natural Selection ◽  
Sex Ratio ◽  
Collective Behavior ◽  
Genetic Correlations ◽  
Natural Populations ◽  
The Body ◽  
Collective Behaviors ◽  
Fitness Consequences ◽  
Caste Ratio

AbstractCollective behaviors are widespread in nature and usually assumed to be strongly shaped by natural selection. However, the degree to which variation in collective behavior is heritable and has fitness consequences -- the two prerequisites for evolution by natural selection -- is largely unknown. We used a new pharaoh ant (Monomorium pharaonis) mapping population to estimate the heritability, genetic correlations, and fitness consequences of three collective behaviors (foraging, aggression, and exploration) as well as body size, sex ratio, and caste ratio. Heritability estimates for the collective behaviors were moderate, ranging from 0.17 to 0.32, but lower than our estimates for the heritability of caste ratio, sex ratio, and the body size of new workers, queens, and males. Moreover, variation among colonies in collective behaviors was phenotypically correlated, suggesting that selection may shape multiple colony collective behaviors simultaneously. Finally, we found evidence for directional selection that was similar in strength to estimates of selection in natural populations. Altogether, our study begins to elucidate the genetic architecture of collective behavior and is one of the first studies to demonstrate that it is shaped by selection.

Observations on activity, display behavior, coloration and androgen levels in the keeled earless lizard, Holbrookia propinqua

1991 ◽  
Vol 12 (1) ◽  
pp. 57-66 ◽  
Author(s):  
William E. Cooper ◽  
Louis J. Guillette
Keyword(s):  
Body Size ◽  
Small Sample Size ◽  
Small Sample ◽  
Male Body ◽  
Observation Distance ◽  
Large Size ◽  
Color Morphs ◽  
Body Sizes ◽  
Selection For ◽  
The Relationship

AbstractWe observed the distance moved, number of movements, and frequency of displays in ten minute intervals for two male color morphs, coral and yellow, and for brightly colored females, of Holbrookia propinqua. We also measured body sizes and, for males, plasma androgen concentrations. Distance moved, number of movements, and number of social displays were positively correlated in males. Females exhibited similar correlations, but the relationship between distance moved and number of displays was not significant. Males moved more often and greater distances than females. Females performed displays as frequently as did males, perhaps because we selected large, dominant females for observation. Distance moved, number of movements, and number of displays increased with body size in males. That these relationships did not hold in females may indicate a sex difference or reflect the small sample size and body size range of females. Plasma androgen concentrations increased with male body size, suggesting a possible androgenic mechanism of sexual selection for large size. Androgen level did not affect display frequency or distance moved. Distance moved increased with plasma androgen concentration, but when effects of body size were held constant, this relationship vanished. Coral and yellow males did not differ in androgen concentration, size, or in the observed behaviors.

scholarly journals GENETIC ANALYSIS OF BROWN ADIPOSE TISSUE, OBESITY AND GROWTH IN MICE

Genetics ◽  
1984 ◽  
Vol 106 (4) ◽  
pp. 705-718
Author(s):  
A M Saxton ◽  
E J Eisen
Keyword(s):  
Body Weight ◽  
Adipose Tissue ◽  
Body Size ◽  
Brown Adipose Tissue ◽  
Genetic Parameters ◽  
Control Diet ◽  
Correlated Response ◽  
High Fat ◽  
Brown Adipose ◽  
Selection For

ABSTRACT The hypothesis developed from single-gene mutant obese rodents that brown adipose tissue (BAT), through its thermogenic ability, is an important factor in the development of obesity, was tested in a randombred population of mice in which degree of adiposity is polygenically determined. Additive direct genetic parameters for measures of body size, lean, fatness and BAT at 6 wk of age were estimated under control and high-fat postweaning dietary regimens. Heritabilities were generally similar for the two diets. However, the lipid-free dry (LFD) component of BAT had a heritability estimate of 0.70 ± 0.26 on the control diet, but only 0.09 ± 0.20 on the high-fat diet. For all traits, genotype by diet interactions indicated that additive direct genetic rankings were not significantly different for the two diets. Based on estimates of genetic parameters in the control diet, selection for 6-wk body weight or 3- to 6-wk gain is expected to increase body size and adiposity. Selection for BAT weight is predicted to result in large, lean individuals. However, selection for the LFD content of BAT, generally believed to be a better indicator of thermogenic ability, is predicted to increase fatness as well as body size. Selection for LFD as a proportion of 6-wk body weight reduced the expected correlated response in fatness. It was concluded that BAT does not play a major role in determining the correlated response in obesity that is often found in populations selected for large body size.

129 Genomic Relationship Between PRRSV Wild-type Infection and PRRSV Vaccination for Antibody Response and Reproductive Performance

2021 ◽  
Vol 99 (Supplement_1) ◽  
pp. 18-18
Author(s):  
Leticia P Sanglard ◽  
Felipe Hickmann ◽  
Yijian Huang ◽  
Kent A Gray ◽  
Daniel Linhares ◽  
...  
Keyword(s):  
Antibody Response ◽  
Reproductive Performance ◽  
Genetic Correlations ◽  
Clinical Signs ◽  
Respiratory Syndrome Virus ◽  
Wild Type ◽  
Large White ◽  
Selection For ◽  
Indicator Trait ◽  
Type Infection

Abstract Immunoglobulin G antibody response, measured as sample-to-positive (S/P) ratio, to Porcine Reproductive and Respiratory Syndrome virus (PRRSV) has been proposed as an indicator trait for improved reproductive performance in PRRSV-infected purebred sows and PRRSV-vaccinated crossbred gilts. In this study, we investigated the genetic correlations (rg) of S/P ratio following a PRRSV outbreak and PRRSV-vaccination with performance in non-exposed and PRRSV-exposed sows. PRRSV outbreak phase was defined based on previously described methodologies after the detection of typical clinical signs of PRRSV infection. 541 Landrace sows had S/P ratio measured at ~54 days after the beginning of the PRRSV outbreak (S/Poutbreak), and 906 Landrace x Large White naïve F1 gilts had S/P ratio measured at ~50 days after vaccination with a commercial modified live PRRSV vaccine (S/PVx). 711 and 428 Landrace sows had reproductive performance recorded before and during the PRRSV outbreak, respectively. 811 vaccinated F1 animals had farrowing performance for up to 3 parities. All animals were genotyped for ~28K SNPs. The estimate of rg of S/Poutbreakwith S/PVx was high (rg±SE = 0.72±0.18). Estimates of rg of S/Poutbreak with reproductive performance in F1 sows were low to moderate, ranging from 0.05±0.23 (number stillborn) to 0.30±0.20 (total number born). Estimates of rg of S/PVxwith reproductive performance in non-infected purebred sows were moderate and favorable with number born alive (0.50±0.23), but low (0 to -0.11±0.23) with litter mortality traits. Estimates of rg of S/PVx were moderate and negative (-0.47±0.18) with the number of mummies in PRRSV-infected purebred sows and low with other traits (-0.29±0.18 for total number born to 0.05±0.18 for number stillborn). These results indicate that selection for antibody response following a PRRSV outbreak collected in purebred sows and to PRRSV vaccination collected in commercial crossbred gilts may increase litter size of non-infected and PRRSV-exposed purebred and commercial crossbred sows.

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 Polygenic and single gene responses to selection for resistance to diazinon in Lucilia cuprina.

Genetics ◽  
1992 ◽  
Vol 130 (3) ◽  
pp. 613-620 ◽  
Author(s):  
J A McKenzie ◽  
A G Parker ◽  
J L Yen
Keyword(s):  
Resistant Strain ◽  
Single Gene ◽  
Natural Populations ◽  
Susceptible Strain ◽  
Selection Line ◽  
Base Population ◽  
Gene Response ◽  
Biochemical Profiles ◽  
Resistant Strains ◽  
Selection For

Abstract Following mutagenesis with ethyl methanesulfonate, selection in a susceptible strain with a concentration of the insecticide diazinon (0.0004%, w/v) above that required to kill 100% of the susceptible strain, the LC100 of that strain, resulted in a single gene response. The resultant four mutant resistant strains have equivalent physiological, genetical and biochemical profiles to a diazinon-resistant strain derived from a natural population and homozygous for the Rop-1 allele. Modification of the microsomal esterase E3 is responsible for resistance in each case. The Rop-1 locus maps approximately 4.4 map units proximal to bu on chromosome IV. Selection within the susceptible distribution, at a concentration of diazinon [0.0001% (w/v)] less than the LC100, resulted in a similar phenotypic response irrespective of whether the base population had been mutagenized. The responses were polygenically based, unique to each selection line and independent of Rop-1. The relevance of the results to selection for insecticide resistance in laboratory and natural populations is discussed.

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