PLOIDY DOES NOT AFFECT FLUCTUATING ASYMMETRY IN THE CARPENTER BEE (HYMENOPTERA: ANTHOPHORIDAE)

2000 ◽  
Vol 132 (3) ◽  
pp. 333-335 ◽  
Author(s):  
Shin-ichi Kudo ◽  
Sachiko Mori

Random deviations from perfect symmetry in bilateral traits, fluctuating asymmetry, are thought to reflect developmental stability: the ability of an individual to buffer against genetic and (or) environmental stress during development (Palmer and Strobeck 1986). Fluctuating asymmetry is often regarded as an indicator of individual quality or fitness (Møller and Swaddle 1997); however, factors underlying fluctuating asymmetry are not well understood (Markow 1995). It has been suggested that heterozygosity, ploidy, and genomic coadaptation (hybridization) are genetic factors affecting the magnitude of fluctuating asymmetry (Palmer and Strobeck 1986; Markow 1995; Møller and Swaddle 1997). Insects having a haplodiploid sex-determining mechanism present opportunities to examine the relationship between ploidy and fluctuating asymmetry. In hymenopterans, females are diploid and males haploid. Thus the effects of ploidy can be investigated by contrasting males and females within a population (e.g., Clarke 1997). Diploid females, in which deleterious recessives reducing developmental stability could be masked, may be expected to have smaller asymmetry than haploid males (e.g., Brückner 1976; Smith et al. 1997). In this paper, we compare the level of fluctuating asymmetry in forewing venation of males to that of females in the carpenter bee Xylocopa appendiculata circumvolans Smith.

2020 ◽  
Vol 64 ◽  
pp. 14-17
Author(s):  
S Kasture ◽  
M Sharma ◽  
MS Nataraja

Introduction: Aircrew are repetitively exposed to positive Gz acceleration in fighter flying. Factors affecting +Gz tolerance vary among individuals and are determined by both modifiable and non-modifiable factors. Some of the non-modifiable factors influencing +Gz tolerance are age, gender, and height. The present study was undertaken to understand the relationship of these variables with relaxed +Gz tolerance. Material and Methods: The study involved a retrospective analysis of existing database of the high-performance human centrifuge at the Institute of Aerospace Medicine. Relevant data from 70 non-aircrew subjects were included for the study. Of these, 39 were male and 31 were female. The age and height varied from 27 to 38 years and 157 to 187 cm, respectively. The data were analyzed using Microsoft Office Excel® to find the correlation between age and height with relaxed +Gz tolerance. Relaxed +Gz tolerance of men and women was compared using unpaired t-test. Significance was set at P < 0.05. Results: The mean age, height, and relaxed +Gz tolerance of males were found to be 30.25 ± 4.3 years, 172.58 ± 6.5 cm, and 4.89 ± 0.67G, respectively, whereas those of females were 27.28 ± 3.36 years, 158.46 ± 6.78 cm, and 4.4 ± 0.85G, respectively. In both males and females, age and height showed no correlation with relaxed +Gz tolerance. However, the relaxed +Gz tolerance was found to be higher in males and this difference was statistically different (P = 0.008). Conclusion: Age and height showed no correlation with relaxed +Gz tolerance in both males and females nonaircrew subjects. Males exhibited a statistically significant, higher relaxed +Gz tolerance as compared to females.


2015 ◽  
Vol 93 (11) ◽  
pp. 833-840 ◽  
Author(s):  
Margarita Miklasevskaja ◽  
Laurence Packer

Fluctuating asymmetry (FA), random deviations from perfect symmetry in bilateral traits, is a common inverse measure of developmental stability (DS), which is related to one’s ability to buffer against environmental and genetic perturbations. There is a widespread hypothesis that heterozygosity grants an increased ability to compensate for developmental errors caused by genetic and environmental factors, rendering homozygous individuals less symmetric than heterozygous ones. In addition, if natural selection on FA is common, nonessential traits should exhibit higher asymmetry than functionally essential traits. This is especially well tested in haplodiploid organisms, which present a clear distinction between “homo”zygosity (males) and heterozygosity (females). Relatively few FA studies looked at this relationship in hymenopterans or in haplodiploid organisms in general and the results are rather inconsistent. This study compares FA measurements of seven parts of the maxillary palpus, with sclerotized and membranous parts scored separately, and two wing venation characters for males and females of the Chilean bee Xeromelissa rozeni (Toro and Moldenke, 1979). The results of this study suggest that there is an equally strong selection force for maxillary palp symmetry in both males and females leading to a relatively low FA in both sexes, and that less functional traits exhibit higher FA due to relaxation of selection. Lastly, we stress the importance of testing a larger number of independent traits.


2006 ◽  
Vol 33 (4) ◽  
pp. 313 ◽  
Author(s):  
Bonnie Lauck

Fluctuating asymmetry has been proposed as an indicator of environmental stress and population health. However, a notable feature of research examining the relationship between fluctuating asymmetry and population fitness is that of inconsistency. Logging dramatically alters habitat and has the potential to increase or decrease environmental stress. To evaluate the response of fluctuating asymmetry to logging, I conducted research to determine whether fluctuating asymmetry differs in the frog Crinia signifera captured at logged and unlogged sites and if any differences were correlated with body size or body condition. There was a decrease in fluctuating asymmetry but also a decrease in body size and body condition as a result of logging. I also investigated whether any relationship existed between the subtle asymmetry of individuals and the following indicators of fitness: clutch size, clutch mass, average egg mass, testes size, body size and body condition. There was no significant relationship between subtle asymmetry and the fitness indicators.


2011 ◽  
Vol 1 ◽  
pp. 121-128
Author(s):  
Muhammad Masood Tariq ◽  

Data on birth weight of 2377 lambs obtained from 581 dams and 56 sires of Mengali sheep born during 2005 and 2009 were recorded and analyzed to identify the factors affecting birth weight of Mengali lambs. Mengali flocks were kept under semi-intensive condition in four stations at three different locations (Experimental Station Center for Advanced studies in Vaccinology and Biotechnology (CASVAB), University of Balochistan, (ESC), Quetta, Killi Hassni, Quetta; Khadkucha, Mastung and Peer Wala (Mal), Nushki). The lambing occurred spring and autumn, however majority of the Mengali sheep (85 %) lambed during spring between (February and March months). Among the total lambs born, the male to female sex ratio was 49.43: 50.57 respectively and shown no significant difference between two sexes. The overall least-squares means for birth weight of males and females pooled over parity and type of birth were 3.61±0.36 and 3.48±0.39 kg respectively


2000 ◽  
Vol 135 (1) ◽  
pp. 85-89 ◽  
Author(s):  
M. MELLADO ◽  
J. L. AMARO ◽  
J. E. GARCÍA ◽  
L. M. LARA

Data on 1468 pregnancies and 2356 newborn goat kids of six genetic groups under intensive management were utilized to determine some genetic and non-genetic factors affecting gestation length, and to assess the relationship between gestation length and survival of kids to 25 days of age. The study revealed significant (P < 0·01) effect of breed of dam, litter weight, breeding season and parity on gestation length. Number of kids born and sex of kids were not a significant source of variation affecting this trait. Granadina goats had the shortest gestation (149·0±0·31 days), whereas Toggenburg (151·7±0·28 days) and Alpine (151·4±0·46 days) had the longest. Litter weight and gestation period were related curvilinearly in summer and linearly in autumn. Gestation of goats bred in summer was 1 day longer (P < 0·01) than those mated in the autumn. There was a progressive reduction of gestation length as parity increased (151·3±0·24, 150·6±0·17 and 149·9±0·39 days for 1, 2·6 and > 7 kiddings, respectively). The mean survival rate of kids gestated < 148 days and 148–;152 days were 78±2 and 87±1, respectively, and these were significantly lower (P < 0·05) than the survival rate of kids gestated 152–156 days and > 156 days (94±1 and 95±2). In conclusion, prolonged gestation (152–160 days) in goats was beneficial because it resulted in heavier litters at birth and higher viability of neonatal kids.


PeerJ ◽  
2017 ◽  
Vol 5 ◽  
pp. e3359
Author(s):  
Clara M.A. ten Broek ◽  
Jessica Bots ◽  
Marianna Bugiani ◽  
Frietson Galis ◽  
Stefan Van Dongen

Disturbance from the normal developmental trajectory of a trait during growth—the so-called developmental instability—can be observed morphologically through phenodeviants and subtle deviations from perfect symmetry (fluctuating asymmetry). This study investigates the relationship between phenodeviance in the human vertebral column (as a result of axial patterning defects) and limb fluctuating asymmetry. Since both types of markers of developmental instability have been found associated with congenital abnormalities in humans, we anticipate a relationship between them if the concept of developmental instability, measured through either phenodeviants or asymmetry, would reflect an organism-wide process. Yet we did not find any support for this hypothesis. We argue that the vast differences in the developmental processes involved in both systems renders these two markers of developmental instability unrelated, in spite of their associations with other congenital abnormalities. Our results thus contribute to the growing awareness that developmental instability is not an organism-wide property.


2004 ◽  
Vol 9 (1) ◽  
pp. 43-55 ◽  
Author(s):  
Patrizia Vermigli ◽  
Alessandro Toni

The present research analyzes the relationship between attachment styles at an adult age and field dependence in order to identify possible individual differences in information processing. The “Experience in Close Relationships” test of Brennan et al. was administered to a sample of 380 individuals (160 males, 220 females), while a subsample of 122 subjects was given the Embedded Figure Test to measure field dependence. Confirming the starting hypothesis, the results have shown that individuals with different attachment styles have a different way of perceiving the figure against the background. Ambivalent and avoidant individuals lie at the two extremes of the same dimension while secure individuals occupy the central part. Significant differences also emerged between males and females.


2020 ◽  
Vol 16 (5) ◽  
pp. 935-945
Author(s):  
I.A. Zaikova

Subject. The working time of workers at any stage of economic development is a value reflecting the level of labor productivity. Any progress in productivity contributes to changes in the volume of labor costs and the number of employed. Depending on the relationship between the total volume of labor costs and the number of employed, the duration of working time per one worker may change (it may increase, decrease, or remain unchanged). Objectives. The study aims to confirm the importance of such a macroeconomic indicator as the number of employed in varying working hours. Methods. The study rests on the comparative analysis of countries with developed economies based on some indicators like dynamics of the working time fund, dynamics of the number of employed, average number of hours worked during the year per employee, etc. The analyzed timespan is 25 years (from 1991 to 2016). Results. The comparative analysis revealed that in the non-production sphere and the economy as a whole the macroeconomic determinants correlate so that the length of working time per worker reduces. When considering the analysis results for the manufacturing sector, no single trend was identified. Conclusions. One of the key factors affecting the change in working hours is the number of employed. The relationship between the working time fund and the number of employed directly determines the dynamics of working time per worker.


Author(s):  
В.А. Бывальцев ◽  
И.А. Степанов ◽  
Е.Г. Белых ◽  
А.И. Яруллина

Цель обзора - анализ современных данных литературы о нарушении внутриклеточных сигнальных путей, играющих ведущую роль в развитии менингиом, генетических и молекулярных профилях данной группы опухолей. К настоящему времени изучено множество аберрантных сигнальных внутриклеточных путей, которые играют важнейшую роль в развитии менингиом головного мозга. Четкое понимание поврежденных внутриклеточных каскадов поможет изучить влияние генетических мутаций и их эффектов на менингиомогенез. Подробное исследование генетического и молекулярного профиля менингиом позволит сделать первый уверенный шаг в разработке более эффективных методов лечения данной группы интракраниальных опухолей. Хромосомы 1, 10, 14, 22 и связанные с ними генные мутации ответственны за рост и прогрессию менингиом. Предполагается, что только через понимание данных генетических повреждений будут реализованы новейшие эффективные методы лечения. Будущая терапия будет включать в себя комбинации таргетных молекулярных агентов, в том числе генную терапию, малые интерферирующие РНК, протонную терапию и другие методы воздействия, как результат дальнейшего изучения генетических и биологических изменений, характерных для менингеальных опухолей. Meningiomas are by far the most common tumors arising from the meninges. A myriad of aberrant signaling pathways involved with meningioma tumorigenesis, have been discovered. Understanding these disrupted pathways will aid in deciphering the relationship between various genetic changes and their downstream effects on meningioma pathogenesis. An understanding of the genetic and molecular profile of meningioma would provide a valuable first step towards developing more effective treatments for this intracranial tumor. Chromosomes 1, 10, 14, 22, their associated genes, have been linked to meningioma proliferation and progression. It is presumed that through an understanding of these genetic factors, more educated meningioma treatment techniques can be implemented. Future therapies will include combinations of targeted molecular agents including gene therapy, si-RNA mediation, proton therapy, and other approaches as a result of continued progress in the understanding of genetic and biological changes associated with meningiomas.


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