Phenotypic characterisation of extreme growth-selected mouse lines: An important prerequisite for future QTL analysis

2006 ◽  
Vol 1 (3) ◽  
pp. 345-375 ◽  
Author(s):  
Ulla Renne ◽  
Gerhard Dietl ◽  
Martina Langhammer ◽  
Charlotte Rehfeldt ◽  
Karin Nürnberg ◽  
...  
Keyword(s):  
Growth Traits ◽  
High Growth ◽  
Rectus Femoris ◽  
Selection Response ◽  
Physiological Basis ◽  
Highest Weight ◽  
Body Conformation ◽  
Phenotypic Characterisation ◽  
Mouse Lines

AbstractA unique set of seven mouse lines, long-term selected for high growth, from different laboratories around the world has been comprehensively compared to evaluate these resources for future QTL and gene mapping for growth traits. The heaviest line (DUH) was 40% (males) to 44% (females) heavier than the smallest line (ROH) at birth, and 105% (males) to 114% (females) heavier at 98 d. Body conformation (body length and width, body areas), body composition (dry matter, fat, fatty acid composition, organ weights), and skeletal muscle cellularity also differed substantially. DUH was more than 20% longer (12.3 cm) compared to the shortest line ROH (9.7 cm). DAH (22.5%) had the highest percentage of gonadal fat and the leanest was BEH (7.7%). Line BEH (0.49 g) showed the highest weight for the left M. rectus femoris, which was 2.1 times higher, compared to ROH (0.23 g). These results suggest that different alleles, and possibly different physiological pathways, have contributed to the selection response in the different lines. Therefore these selection lines are an important tool with which to identify the genetic and physiological basis of growth as they may contain many, if not all, growth promoting alleles.

scholarly journals Effect of exercise on sarcoplasmic reticulum Ca<sup>2+</sup> transport in muscle of mouse lines long-term selected for different Performance traits

2001 ◽  
Vol 44 (4) ◽  
pp. 441-450
Author(s):  
U. Küchenmeister ◽  
M. Langhammer ◽  
U. Renne ◽  
G. Nürnberg ◽  
K. Ender
Keyword(s):  
Rectus Femoris ◽  
Control Line ◽  
Maximal Rate ◽  
Open Field Activity ◽  
The Third ◽  
Field Activity ◽  
Low Performance ◽  
Exercise Induced ◽  
Mouse Lines

Abstract. Mouse lines used were long-term selected for high (DU-hTP) or low treadmill Performance (DU-ITP), or high locomotor open field activity (DU-hOF). The control line DU-Ks was maintained unselected. For each line 30 mice were used at 42 days of age. All lines were split into three groups: the first group was investigated without running exercise, the second had to run 500 m, and the third had to run until exhaustion on the treadmill. Compared to mice without running, in exhausted mice the maximal rate of SR Ca2+ uptake of the m. rectus femoris decreases were only found in the mouse lines DU-ITP, and DU-hOF (28.5 %, and 36.3 %, respectively; p < 0.05). The effect of the 500 m run was significant (p < 0.05) in DU-hTP, but not in the other lines. An effect of exhausting exercise on Ca2* ATPase was detected only in DU-hOF with increased values after the exhaustive run. The hypothesis, that exercise induced alterations in Ca2* transport in muscle of mice selected for high activity (DU-hOF) or high running Performance (DU-hTP) are attenuated compared to mice which were not selected (DU-Ks) or selected for low Performance (DU-ITP), could not be verified.

scholarly journals Phenotypic Characterisation for Growth and Nut Characteristics Revealed the Extent of Genetic Diversity in Wild Macadamia Germplasm

Agriculture ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 680
Author(s):  
Thuy T. P. Mai ◽  
Craig M. Hardner ◽  
Mobashwer M. Alam ◽  
Robert J. Henry ◽  
Bruce L. Topp
Keyword(s):  
Genetic Diversity ◽  
Growth Traits ◽  
Principal Component ◽  
Conservation Strategies ◽  
Wild Germplasm ◽  
Phenotypic Characterisation ◽  
Wide Range ◽  
Genetic And Environmental Factors ◽  
Positive Correlations ◽  
Wild Accessions

Macadamia is a recently domesticated Australian native nut crop, and a large proportion of its wild germplasm is unexploited. Aiming to explore the existing diversity, 247 wild accessions from four species and inter-specific hybrids were phenotyped. A wide range of variation was found in growth and nut traits. Broad-sense heritability of traits were moderate (0.43–0.64), which suggested that both genetic and environmental factors are equally important for the variability of the traits. Correlations among the growth traits were significantly positive (0.49–0.76). There were significant positive correlations among the nut traits except for kernel recovery. The association between kernel recovery and shell thickness was highly significant and negative. Principal component analysis of the traits separated representative species groups. Accessions from Macadamia integrifolia Maiden and Betche, M. tetraphylla L.A.S. Johnson, and admixtures were clustered into one group and those of M. ternifolia F. Muell were separated into another group. In both M. integrifolia and M. tetraphylla groups, variation within site was greater than across sites, which suggested that the conservation strategies should concentrate on increased sampling within sites to capture wide genetic diversity. This study provides a background on the utilisation of wild germplasm as a genetic resource to be used in breeding programs and the direction for gene pool conservation.

scholarly journals Selection Response in Finite Populations

Genetics ◽  
1996 ◽  
Vol 144 (4) ◽  
pp. 1961-1974 ◽  
Author(s):  
Ming Wei ◽  
Armando Caballero ◽  
William G Hill
Keyword(s):  
Linkage Disequilibrium ◽  
Inbreeding Depression ◽  
Genetic Variance ◽  
Relative Rate ◽  
Selection Response ◽  
Rate Of Change ◽  
Effective Population ◽  
Short Term ◽  
Model Account

Formulae were derived to predict genetic response under various selection schemes assuming an infinitesimal model. Account was taken of genetic drift, gametic (linkage) disequilibrium (Bulmer effect), inbreeding depression, common environmental variance, and both initial segregating variance within families (σAW02) and mutational (σM2) variance. The cumulative response to selection until generation t(CRt) can be approximated asCRt≈R0[t−β(1−σAW∞2σAW02)t24Ne]−Dt2Ne,where Ne is the effective population size, σAW∞2=NeσM2 is the genetic variance within families at the steady state (or one-half the genic variance, which is unaffected by selection), and D is the inbreeding depression per unit of inbreeding. R  0 is the selection response at generation 0 assuming preselection so that the linkage disequilibrium effect has stabilized. β is the derivative of the logarithm of the asymptotic response with respect to the logarithm of the within-family genetic variance, i.e., their relative rate of change. R  0 is the major determinant of the short term selection response, but σM2, Ne and β are also important for the long term. A selection method of high accuracy using family information gives a small Ne and will lead to a larger response in the short term and a smaller response in the long term, utilizing mutation less efficiently.

Founders without Limits

2021 ◽  
Author(s):  
Bobby V. Reddy
Keyword(s):  
Stock Exchange ◽  
High Growth ◽  
Global History ◽  
Public Markets ◽  
The Us ◽  
History Of ◽  
The Uk ◽  
Dual Class ◽  
Blue Chip

Big Tech has flourished on the US public markets in recent years with numerous blue-chip IPOs, from Google and Facebook, to new kids on the block such as Snap, Zoom, and Airbnb. A key trend is the burgeoning use of dual-class stock. Dual-class stock enables founders to divest of equity and generate finance for growth through an IPO, without losing the control they desire to pursue their long-term, market-disrupting visions. Bobby Reddy scrutinises the global history of dual-class stock, evaluates the conceptual and empirical evidence on dual-class stock, and assesses the approach of the London Stock Exchange and ongoing UK regulatory reforms to dual-class stock. A policy roadmap is presented that optimally supports the adoption of dual-class stock while still protecting against its potential abuses, which will more effectively attract high-growth, innovative companies to the UK equity markets, boost the economy, and unleash the true potential of 'founders without limits'.

scholarly journals LONG-TERM SELECTION RESPONSE FOR 12-DAY LITTER WEIGHT IN MICE

Genetics ◽  
1972 ◽  
Vol 72 (1) ◽  
pp. 129-142
Author(s):  
E J Eisen
Keyword(s):  
Body Weight ◽  
Genetic Correlation ◽  
Half Life ◽  
Selection Process ◽  
Selection Response ◽  
Exponential Model ◽  
Correlated Response ◽  
Term Selection ◽  
Litter Weight

ABSTRACT Long-term selection for increased 12-day litter weight in two replicate lines (W2, W3) of mice resulted in an apparent selection limit at about 17 generations. Quadratic polynomial and exponential models were fitted to the data in order to estimate the plateaued response and half-life of the selection process. Using the polynomial results, the half-life estimates were 4.5 and 8.6 generations for W2 and W3, respectively. The plateaued responses were 5.1 and 5.8 g which, when expressed in phenotypic standard deviation units, became 1.1 and 1.3. The exponential model provides similar estimates. A negative association between 12-day litter weight and fitness was not considered to be an adequate explanation for the plateau since there was no decrease in fertility of the selected lines. Evidence that exhaustion of genetic variability was not the cause of the plateau came from the immediate response to reverse selection. It was proposed that the plateau may be due to a negative genetic correlation between direct and maternal genetic effects, which would be expected to occur after many generations of selection. There were positive correlated responses in both replicates for adult body weight, which was in agreement with the positive genetic correlation between preweaning and postweaning body weight. The expected positive correlated response for number born was realized in only one of the replicates.

scholarly journals Non-Specific Interactions of Rhizospheric Microbial Communities Support the Establishment of Mimosa acutistipula var. ferrea in an Amazon Rehabilitating Mineland

Processes ◽  
2021 ◽  
Vol 9 (11) ◽  
pp. 2079
Author(s):  
Paulo Henrique de Oliveira Costa ◽  
Sidney Vasconcelos do Nascimento ◽  
Hector Herrera ◽  
Markus Gastauer ◽  
Silvio Junio Ramos ◽  
...  
Keyword(s):  
Microbial Communities ◽  
Mycorrhizal Fungi ◽  
Soil Microorganisms ◽  
High Growth ◽  
Biodiversity Hotspot ◽  
Soil Processes ◽  
Specific Interactions ◽  
Bacterial Phyla ◽  
Wide Range

Mimosa acutistipula var. ferrea (Fabaceae) is endemic to ferruginous tropical rocky outcrops in the eastern Amazon, also known as canga. Canga are often associated with mining activities and are the target of protection and rehabilitation projects. M. acutistipula stands out in this biodiversity hotspot with high growth rates, even in rehabilitating minelands (RMs). However, little is known about the diversity of soil microorganisms interacting with M. acutistipula in canga and RMs. This study analyzed the rhizosphere-associated bacterial and fungal microbial communities associated with M. acutistipula growing in an RM and a native shrub canga. The fungal phylum Ascomycota was the dominant taxa identified in the rhizosphere of the canga (RA: 98.1) and RM (RA: 93.1). The bacterial phyla Proteobacteria (RA: 54.3) and Acidobacteria (RA: 56.2) were the dominant taxa identified in the rhizosphere in the canga and RM, respectively. Beneficial genera such as Bradyrhizobium, Rhodoplanes, and Paraconiothyrium were identified in the rhizosphere of M. acutistipula in both areas. However, the analyses showed that the fungal and bacterial diversity differed between the rhizosphere of the canga and RM, and that the microbial taxa adapted to the canga (i.e., Rasamsonia, Scytalidium, Roseiarcus, and Rhodomicrobium) were lacking in the RM. This influences the microbe-mediated soil processes, affecting long-term rehabilitation success. The results showed that M. acutistipula established non-specific interactions with soil microorganisms, including beneficial taxa such as nitrogen-fixing bacteria, mycorrhizal fungi, and other beneficial endophytes, well known for their importance in plant adaptation and survival. High levels of microbe association and a plant’s ability to recruit a wide range of soil microorganisms help to explain M. acutistipula’s success in rehabilitating minelands.

scholarly journals Accumulation of mutations affecting body weight in inbred mouse lines

1995 ◽  
Vol 65 (2) ◽  
pp. 145-149 ◽  
Author(s):  
Armando Caballero ◽  
Peter D. Keightley ◽  
William G. Hill
Keyword(s):  
Body Weight ◽  
Maximum Likelihood ◽  
Genetic Variance ◽  
Inbred Mouse ◽  
Additive Genetic Variance ◽  
Selection Response ◽  
Spontaneous Mutations ◽  
Line Selection ◽  
Divergence Estimates ◽  
Mouse Lines

SummaryThe variation from spontaneous mutations for 6-week body weight in the mouse was estimated by selection from a cross of two inbred sublines, C57BL/6 and C57BL/10, separated about 50 years previously from the same inbred line. Selection was practised high and low for 12 generations from theF2, followed by one generation of relaxation. The lines diverged by approximately 1·7 g or 0·7 sd. The additive genetic variance was estimated in theF2by restricted maximum likelihood and from the selection response, and from this variance the mutational heritabilityhM2was estimated using the number of generations since divergence. Estimates ofhM2range from 0·08 to 0·10% depending on the method of analysis. These estimates are similar to those found for other species, but lower than other estimates for the mouse. It is concluded that substantial natural and, perhaps, artificial selection operated during the maintenance of the sublines.

scholarly journals Minimal invasive microscopic tooth preparation in esthetic restoration: a specialist consensus

2019 ◽  
Vol 11 (3) ◽  
Author(s):  
Haiyang Yu ◽  
Yuwei Zhao ◽  
Junying Li ◽  
Tian Luo ◽  
Jing Gao ◽  
...  
Keyword(s):  
Minimally Invasive ◽  
Critical Role ◽  
Minimal Invasive ◽  
Therapeutic Effects ◽  
Preparation Technique ◽  
Finish Line ◽  
Physiological Basis ◽  
Core Elements ◽  
Tooth Preparation

Abstract By removing a part of the structure, the tooth preparation provides restorative space, bonding surface, and finish line for various restorations on abutment. Preparation technique plays critical role in achieving the optimal result of tooth preparation. With successful application of microscope in endodontics for >30 years, there is a full expectation of microscopic dentistry. However, as relatively little progress has been made in the application of microscopic dentistry in prosthodontics, the following assumptions have been proposed: Is it suitable to choose the tooth preparation technique under the naked eye in the microscopic vision? Is there a more accurate preparation technology intended for the microscope? To obtain long-term stable therapeutic effects, is it much easier to achieve maximum tooth preservation and retinal protection and maintain periodontal tissue and oral function health under microscopic vision? Whether the microscopic prosthodontics is a gimmick or a breakthrough in obtaining an ideal tooth preparation should be resolved in microscopic tooth preparation. This article attempts to illustrate the concept, core elements, and indications of microscopic minimally invasive tooth preparation, physiological basis of dental pulp, periodontium and functions involved in tool preparation, position ergonomics and visual basis for dentists, comparison of tooth preparation by naked eyes and a microscope, and comparison of different designs of microscopic minimally invasive tooth preparation techniques. Furthermore, a clinical protocol for microscopic minimally invasive tooth preparation based on target restorative space guide plate has been put forward and new insights on the quantity and shape of microscopic minimally invasive tooth preparation has been provided.

scholarly journals Long-term desalinated water demand and investment requirements: a case study of Riyadh

2017 ◽  
Vol 8 (3) ◽  
pp. 432-446 ◽  
Author(s):  
O. K. M. Ouda ◽  
Y. Khalid ◽  
A. H. Ajbar ◽  
M. Rehan ◽  
K. Shahzad ◽  
...  
Keyword(s):  
Water Demand ◽  
Public Awareness ◽  
Groundwater Resources ◽  
High Growth ◽  
Domestic Water ◽  
Awareness Campaigns ◽  
Desalinated Water ◽  
Desalination Plants

Abstract The Kingdom of Saudi Arabia (KSA) is situated in an arid region and faces a chronic challenge to meet its increasing water demand. Riyadh is the capital of KSA and home to about six million people. The water demand is mostly met by groundwater resources (up to 48%), while the desalination plants cover the rest of the water supply requirements. There is a potential risk of a significant gap in water demand–supply due to the retirement of old desalination plants. This study, therefore, developed a probabilistic model to forecast desalinated water demand in Riyadh for domestic purposes up to the year 2040 based on three scenarios: low growth, the most likely (mean), and high growth scenario. The results showed that an investment of about US$6.24, 11.59, and 16.04 billion is required to meet the future domestic water demand of the city for the next 25 years based on low, mean, and high growth scenarios, respectively. Moreover, a strong commitment to public–private partnership is required to remove the fiscal budget burden related to the desalination along with public awareness campaigns to reduce per capita water consumption, upgrading the water tariff system and using renewable energy to run desalination plants.

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