45 research outputs found
The role of endosymbionts in the evolution of haploid-male genetic systems in scale insects (Coccoidea)
No full textThere is an extraordinary diversity in genetic systems across species, but this variation remains poorly understood. In part, this is because the mechanisms responsible for transitions between systems are often unknown. A recent hypothesis has suggested that conflict between hosts and endosymbiotic microorganisms over transmission could drive the transition from diplodiploidy to systems with male haploidy (haplodiploidy, including arrhenotoky and paternal genome elimination [PGE]). Here, we present the first formal test of this idea with a comparative analysis across scale insects (Hemiptera: Coccoidea). Scale insects are renowned for their large variation in genetic systems, and multiple transitions between diplodiploidy and haplodiploidy have taken place within this group. Additionally, most species rely on endosymbiotic microorganisms to provide them with essential nutrients lacking in their diet. We show that species harboring endosymbionts are indeed more likely to have a genetic system with male haploidy, which supports the hypothesis that endosymbionts might have played a role in the transition to haplodiploidy. We also extend our analysis to consider the relationship between endosymbiont presence and transitions to parthenogenesis. Although in scale insects there is no such overall association, species harboring eukaryote endosymbionts were more likely to be parthenogenetic than those with bacterial symbionts. These results support the idea that intergenomic conflict can drive the evolution of novel genetic systems and affect host reproduction.Peer reviewe
The quantitative genetic basis of sex ratio variation in Nasonia vitripennis : a QTL study
No full textOur understanding of how natural selection should shape sex allocation is perhaps more developed than for any other trait. However, this understanding is not matched by our knowledge of the genetic basis of sex allocation. Here, we examine the genetic basis of sex ratio variation in the parasitoid wasp Nasonia vitripennis, a species well known for its response to local mate competition (LMC). We identified a quantitative trait locus (QTL) for sex ratio on chromosome 2 and three weaker QTL on chromosomes 3 and 5. We tested predictions that genes associated with sex ratio should be pleiotropic for other traits by seeing if sex ratio QTL co-occurred with clutch size QTL. We found one clutch size QTL on chromosome 1, and six weaker QTL across chromosomes 2, 3 and 5, with some overlap to regions associated with sex ratio. The results suggest rather limited scope for pleiotropy between these traits.Peer reviewe
On genetics, ecology, and the role of philosophy in evolutionary biology:a reply to Distin
No full textIn this reply, I consider the valuable points raised by Distin in the light of the actuality of evolution as a population genetic process, and how philosophers of science may come to help evolutionary biologists tackle the problems that matter to them
It is the endless forms, stupid:a commentary on Svensson
No full textIn this commentary, I briefly consider the idea raised by Svensson of source laws and consequence laws in evolutionary biology, and use it to review what we might consider to be the canonical processes of biological evolution, focusing in particular on recombination. I then ponder why we have always seen such a variety of evolutionary explanations competing to explain the biodiverse world around us
The curious incident of the wasp in the fig fruit:sex allocation and the extended evolutionary synthesis
No full textHow would we tell if we needed a new evolutionary synthesis? The rationale for the so-called Extended Evolutionary Synthesis (EES) is predicated on there being limitations, failings, or something missing from the current body of theory that evolutionary biologists use when seeking evolutionary explanations for the patterns of biodiversity we see around us. A number of topics have allegedly been neglected or obscured by evolutionary biologists, including the role of development in evolution (“evo-devo”), phenotypic plasticity, niche construction, behaviour, epigenetics, and trans-generational effects. These disparate topics more or less coalesce around two organising principles of EES thinking, that of organismal agency and non-genetic inheritance. In this chapter, I use the field of sex allocation to test the validity of the arguments that these topics have indeed been neglected. Sex allocation is a useful exemplar of evolutionary biology. Thanks to Fisher and Hamilton, it has a historically rich and well-understood theory base. Moreover, across more than five decades, there have been hundreds of empirical tests of components of that theory, across a huge diversity of organisms, such that sex allocation is one of the most successful and well-validated fields within evolutionary biology. If claims of the EES have credence, then the study of sex allocation should clearly highlight what we have missed or ignored. However, I show that all of the components put forward by proponents of the EES as needing to be added into evolutionary biology—with perhaps the exception of cultural evolution, as least outside of humans—have long been studied, implicitly and explicitly by those studying sex allocation. In many cases, the relevant concepts are there at the inception of the modern study of sex allocation, following Hamilton’s ground-breaking paper in 1967. Having dispensed with the need for the EES, I finish by trying to understand why such a synthesis was ever called for in the first place
Nursing students' positively evaluate video exemplars of Objective Structured Clinical Assessments
No full textBackground
The increasing complexity and acuity of patients requires tertiary institutions to provide high quality clinical teaching and assessment of student nurses to adequately prepare them for clinical practice [1]. The use of simulated learning and assessment, such as with Objective Structured Clinical Assessments (OSCAs) is an effective and safe medium to prepare and assess students [2]. However students report them to be stressful which may impact negatively on their performance [3]. Role modelling effective nursing care within clinical scenarios is one method to better prepare students for assessment. Providing clear assessment expectations is important for reducing student anxiety and obtaining examiner consensus moderation [4]. Consequently, a video exemplar using three student actor examples was developed and evaluated by students.
Method
A mixed method approach using surveys and focus groups was used to explore how students utilised the video exemplar to prepare for their OSCA.
Results
A total of 191 students provided feedback data. The average number of times the video exemplar was viewed was nine times. Students reported that specific actors provided more guidance than others. They felt that the video exemplar enabled them to prepare for their OSCA and reinforced expectations. They reported that this reduced their anxiety. However there was no significant increase in student marks from previous years.
Conclusion
The video exemplar provided students multiple examples of role modelling nursing care and gave clear information on how to complete the OSCA including grading expectations. The on-line video access allowed students to revise in preparation for the assessment and clinical practice, enhancing their learning experience and, as self-reported reduced their anxiety. The video exemplar was a valuable tool to encourage student self-assessment and was also used to help ensure assessor reliability, both areas of previous deficit linked to OSCAs.Full Tex
Mating ecology explains patterns of genome elimination
No full textThis research has been supported by a Royal Society University Research Fellowship (AG), a Royal Society Newton International Fellowship (LR) and two NERC Independent Research Fellowships (AG & LR).Genome elimination – whereby an individual discards chromosomes inherited from one parent, and transmits only those inherited from the other parent – is found across thousands of animal species. It is more common in association with inbreeding, under male heterogamety, in males, and in the form of paternal genome elimination. However, the reasons for this broad pattern remain unclear. We develop a mathematical model to determine how degree of inbreeding, sex determination, genomic location, pattern of gene expression and parental origin of the eliminated genome interact to determine the fate of genome-elimination alleles. We find that: inbreeding promotes paternal genome elimination in the heterogametic sex; this may incur population extinction under female heterogamety, owing to eradication of males; and extinction is averted under male heterogamety, owing to countervailing sex-ratio selection. Thus, we explain the observed pattern of genome elimination. Our results highlight the interaction between mating system, sex-ratio selection and intragenomic conflict.Peer reviewe
Integrating volunteers into health authority disaster planning: a review of the literature
No full textThe research question is, how can health authorities proactively prepare for and advance a strong relationship with spontaneous volunteers that present in times of crisis? Without planning and broader acceptance of non-traditional responders to a disaster, health authority Emergency Managers will continue to rely only on traditional disaster planning methodologies and internal personnel to respond to disasters that affect hospital functionality. This is short sighted because the number of staff that respond to the call for help may be less than anticipated creating safety issues (Adams & Berry, 2012).Winner of the 2020 BESMS Student Poster Award of $100. The capstone poster awards are supported by The Justice Institute of British Columbia Foundation, and the Justice & Public Safety and Emergency Management divisions at JIBC.spontaneous volunteers; emergency management; health authorities; preparedness; partnerin
The evolution of hermaphroditism by an infectious male-derived cell lineage : an inclusive-fitness analysis
No full textThis work was supported by funding from Balliol College, the Royal Society (A.G.), and the University of Groningen (L.R.).There has been much recent interest in the role for genetic conflicts to drive the evolution of genetic systems. Here we consider the evolution of hermaphroditism in the scale insect tribe Iceryini and the suggestion that this has been driven by conflict between a female and an infectious male tissue derived from her father. We perform an inclusive-fitness analysis to show that, owing to genetic relatedness between father and daughter, there is scope for collaboration as well as conflict over the establishment of the infectious tissue. We also consider the evolutionary interests of a maternally inherited bacterial symbiont that has been implicated in mediating the tissue's establishment. More generally, our analysis reveals that genetic conflicts can drive the evolution of hermaphroditism.Peer reviewe
