scholarly journals Fitness consequences of biochemical adaptation in Drosophila melanogaster populations under simultaneous selection for faster pre-adult development and extended lifespan

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Khushboo Sharma ◽  
Mallikarjun N. Shakarad

AbstractIn holometabolous insects like Drosophila melanogaster, critical size is an important time point during larval life, for irreversible commitment to metamorphosis. Here, we studied the impact of restricted growth duration in terms of selection for faster pre-adult development in Drosophila melanogaster populations which resulted in the evolution of reduced critical size on adult life history traits. Selection for faster pre-adult development resulted in biochemical adaptation in larval physiology with no compromise in major biomolecules at critical size time point. The flies from the selected populations seem to not only commit to metamorphosis on the attainment of critical size but also seem to channelize resources to reproduction as indicated by similar life-time fecundity of CS and NS flies from selected populations, while the Control CS flies significantly lower life-time fecundity compared to Control NS flies. The flies from selected populations seem to achieve longevity comparable to control flies despite being significantly smaller in size-thus resource constrained due to faster pre-adult development.

2020 ◽  
Author(s):  
Khushboo Sharma ◽  
Mallikarjun N. Shakarad

Abstract BackgroundSilver-spoon hypothesis suggests that fitness of individuals is high under good adult conditions provided their development itself has been in good conditions and those who have grown in resource-poor conditions are at a permanent disadvantage. Using two types of Drosophila melanogaster populations grown under two conditions we tested the validity of silver-spoon hypothesis. Three populations were selected for faster pre-adult development as a result of which they had access to food for a shorter duration while the three control populations had access to food for longer duration as growing larvae. In the second set-up the access to food was curtailed immediately on attainment of critical size. We assessed biomolecule levels, copulation latency, copulation duration, life-time realized oviposition and longevity to validate the silver-spoon hypothesis. ResultsRestricted feeding duration as a consequence of selection for faster per-adult development had no fitness consequences in selected populations. However, starvation during post-critical duration resulted in reduced fitness. ConclusionOur results show that the silver-spoon model is applicable only under extreme nutrition curtailment and not applicable to biological systems that have genetically evolved to limit food intake.


2020 ◽  
Vol 7 (6) ◽  
pp. 191910 ◽  
Author(s):  
Khushboo Sharma ◽  
Nalini Mishra ◽  
Mallikarjun N. Shakarad

Adult body size in holometabolus insects is directly proportional to the time spent during the larval period. The larval duration can be divided into two parts: (i) pre-critical duration—time required to attain a critical size/critical weight that would result in successful completion of development and metamorphosis even under non-availability of nutrition beyond the time of attainment of critical size, and (ii) post-critical duration—the time duration from the attainment of critical size till pupation. It is of interest to decipher the relative contribution of the two larval growth phases (from the hatching of the egg to the attainment of critical size, and from the attainment of critical size to pupation) to the final adult size. Many studies using Drosophila melanogaster have shown that selecting populations for faster development results in the emergence of small adults. Some of these studies have indirectly reported the evolution of smaller critical size. Using two kinds of D. melanogaster populations, one of which is selected for faster/accelerated pre-adult development and the other their ancestral control, we demonstrate that the final adult size is determined by the time spent as larvae post the attainment of critical size despite having increased growth rate during the second larval instar. Our populations under selection for faster pre-adult development are exhibiting adaptive bailout due to intrinsic food limitation as against extrinsic food limitation in the yellow dung fly.


2001 ◽  
Vol 77 (2) ◽  
pp. 135-142 ◽  
Author(s):  
V. LADEVEZE ◽  
S. AULARD ◽  
N. CHAMINADE ◽  
C. BIEMONT ◽  
G. PERIQUET ◽  
...  

The impact of the hobo transposable element in global reorganization of the Drosophila melanogaster genome has been investigated in transgenic lines generated by injection of hobo elements into the Hikone strain, which lacked them. In the present extensive survey, the chromosomal distribution of hobo insertion sites in the line 28 was found to be homogeneous and similar for all chromosomal arms, except 3L, when compared with other transgenic lines. However, some original features were observed in this line at the genetic and chromosomal levels. Several hotspots of insertion sites were observed on the X, second and third chromosomes. Five sites with a high frequency of hobo insertions were present on the 3L arm in most individuals tested, suggesting the action of selection for hobo element in some sites. The presence of doublets or triplet was also observed, implying that hobo inserts can show local jumps or insertions in preferred regions. This local transposition occurred independently in 11 specific genomic regions in many individuals and generations. The dynamics of this phenomenon were analysed across generations. These results support the use of the hobo system as an important tool in fundamental and applied Drosophila genetics.


2020 ◽  
Vol 6 (5) ◽  
pp. 1183-1189
Author(s):  
Dr. Tridibesh Tripathy ◽  
Dr. Umakant Prusty ◽  
Dr. Chintamani Nayak ◽  
Dr. Rakesh Dwivedi ◽  
Dr. Mohini Gautam

The current article of Uttar Pradesh (UP) is about the ASHAs who are the daughters-in-law of a family that resides in the same community that they serve as the grassroots health worker since 2005 when the NRHM was introduced in the Empowered Action Group (EAG) states. UP is one such Empowered Action Group (EAG) state. The current study explores the actual responses of Recently Delivered Women (RDW) on their visits during the first month of their recent delivery. From the catchment area of each of the 250 ASHAs, two RDWs were selected who had a child in the age group of 3 to 6 months during the survey. The response profiles of the RDWs on the post- delivery first month visits are dwelled upon to evolve a picture representing the entire state of UP. The relevance of the study assumes significance as detailed data on the modalities of postnatal visits are available but not exclusively for the first month period of their recent delivery. The details of the post-delivery first month period related visits are not available even in large scale surveys like National Family Health Survey 4 done in 2015-16. The current study gives an insight in to these visits with a five-point approach i.e. type of personnel doing the visit, frequency of the visits, visits done in a particular week from among those four weeks separately for the three visits separately. The current study is basically regarding the summary of this Penta approach for the post- delivery one-month period.     The first month period after each delivery deals with 70% of the time of the postnatal period & the entire neonatal period. Therefore, it does impact the Maternal Mortality Rate & Ratio (MMR) & the Neonatal Mortality Rates (NMR) in India and especially in UP through the unsafe Maternal & Neonatal practices in the first month period after delivery. The current MM Rate of UP is 20.1 & MM Ratio is 216 whereas the MM ratio is 122 in India (SRS, 2019). The Sample Registration System (SRS) report also mentions that the Life Time Risk (LTR) of a woman in pregnancy is 0.7% which is the highest in the nation (SRS, 2019). This means it is very risky to give birth in UP in comparison to other regions in the country (SRS, 2019). This risk is at the peak in the first month period after each delivery. Similarly, the current NMR in India is 23 per 1000 livebirths (UNIGME,2018). As NMR data is not available separately for states, the national level data also hold good for the states and that’s how for the state of UP as well. These mortalities are the impact indicators and such indicators can be reduced through long drawn processes that includes effective and timely visits to RDWs especially in the first month period after delivery. This would help in making their post-natal & neonatal stage safe. This is the area of post-delivery first month visit profile detailing that the current article helps in popping out in relation to the recent delivery of the respondents.   A total of four districts of Uttar Pradesh were selected purposively for the study and the data collection was conducted in the villages of the respective districts with the help of a pre-tested structured interview schedule with both close-ended and open-ended questions.  The current article deals with five close ended questions with options, two for the type of personnel & frequency while the other three are for each of the three visits in the first month after the recent delivery of respondents. In addition, in-depth interviews were also conducted amongst the RDWs and a total 500 respondents had participated in the study.   Among the districts related to this article, the results showed that ASHA was the type of personnel who did the majority of visits in all the four districts. On the other hand, 25-40% of RDWs in all the 4 districts replied that they did not receive any visit within the first month of their recent delivery. Regarding frequency, most of the RDWs in all the 4 districts received 1-2 times visits by ASHAs.   Regarding the first visit, it was found that the ASHAs of Barabanki and Gonda visited less percentage of RDWs in the first week after delivery. Similarly, the second visit revealed that about 1.2% RDWs in Banda district could not recall about the visit. Further on the second visit, the RDWs responded that most of them in 3 districts except Gonda district did receive the second postnatal visit in 7-15 days after their recent delivery. Less than half of RDWs in Barabanki district & just more than half of RDWs in Gonda district received the third visit in 15-21 days period after delivery. For the same period, the majority of RDWs in the rest two districts responded that they had been entertained through a home visit.


2020 ◽  
Author(s):  
Matthew Wade ◽  
Nicola Brown ◽  
James Steele ◽  
Steven Mann ◽  
Bernadette Dancy ◽  
...  

Background: Brief advice is recommended to increase physical activity (PA) within primary care. This study assessed change in PA levels and mental wellbeing after a motivational interviewing (MI) community-based PA intervention and the impact of signposting [SP] and Social Action [SA] (i.e. weekly group support) pathways. Methods: Participants (n=2084) took part in a community-based, primary care PA programme using MI techniques. Self-reported PA and mental wellbeing data were collected at baseline (following an initial 30-minute MI appointment), 12-weeks, six-months, and 12-months. Participants were assigned based upon the surgery they attended to the SP or SA pathway. Multilevel models were used to derive point estimates and 95%CIs for outcomes at each time point and change scores. Results: Participants increased PA and mental wellbeing at each follow-up time point through both participant pathways and with little difference between pathways. Retention was similar between pathways at 12-weeks, but the SP pathway retained more participants at six-months and 12-months. Conclusions: Both pathways produced similar improvements in PA and mental wellbeing, suggesting the effectiveness of MI based PA interventions. However, due to lower resources required yet similar effects, SP pathways are recommended over SA to support PA in primary care settings.


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