抗原变异可使得多种致病微生物易于逃避宿主免疫应答。表达在感染红细胞表面的恶性疟原虫红细胞表面蛋白1（PfPMP1）与感染红细胞、内皮细胞、树突状细胞以及胎盘的单个或多个受体作用，在黏附及免疫逃避中起关键的作用。每个单倍体基因组var基因家族编码约60种成员，通过启动转录不同的var基因变异体为抗原变异提供了分子基础。

疟原虫var基因转换速率变化导致抗原变异[英]／Paul H, Robert P, Christodoulou Z, et al//Proc Natl Acad Sci U S A

So far in this course we have dealt entirely with the evolution of characters that are controlled by simple Mendelian inheritance at a single locus. There are notes on the course website about gametic disequilibrium and how allele frequencies change at two loci simultaneously, but we didn’t discuss them. In every example we’ve considered we’ve imagined that we could understand something about evolution by examining the evolution of a single gene. That’s the domain of classical population genetics. For the next few weeks we’re going to be exploring a field that’s actually older than classical population genetics, although the approach we’ll be taking to it involves the use of population genetic machinery. If you know a little about the history of evolutionary biology, you may know that after the rediscovery of Mendel’s work in 1900 there was a heated debate between the “biometricians” (e.g., Galton and Pearson) and the “Mendelians” (e.g., de Vries, Correns, Bateson, and Morgan). Biometricians asserted that the really important variation in evolution didn’t follow Mendelian rules. Height, weight, skin color, and similar traits seemed to

Human biochemical genetics

Evolutionary adaptation can be rapid and potentially help species counter stressful conditions or realize ecological opportunities arising from climate change. The challenges are to understand when evolution will occur and to identify potential evolutionary winners as well as losers, such as species lacking adaptive capacity living near physiological limits. Evolutionary processes also need to be incorporated into management programmes designed to minimize biodiversity loss under rapid climate change. These challenges can be met through realistic models of evolutionary change linked to experimental data across a range of taxa.

http://www.indiaenvironmentportal.org.in/files/climate%20change_1.pdf

Climate change and evolutionary adaptation

Species distribution models (SDMs) use spatial environmental data to make inferences on species' range limits and habitat suitability. Conceptually, these models aim to determine and map components of a species' ecological niche through space and time, and they have become important tools in pure and applied ecology and evolutionary biology. Most approaches are correlative in that they statistically link spatial data to species distribution records. An alternative strategy is to explicitly incorporate the mechanistic links between the functional traits of organisms and their environments into SDMs. Here, we review how the principles of biophysical ecology can be used to link spatial data to the physiological responses and constraints of organisms. This provides a mechanistic view of the fundamental niche which can then be mapped to the landscape to infer range constraints. We show how physiologically based SDMs can be developed for different organisms in different environmental contexts. Mechanistic SDMs have different strengths and weaknesses to correlative approaches, and there are many exciting and unexplored prospects for integrating the two approaches. As physiological knowledge becomes better integrated into SDMs, we will make more robust predictions of range shifts in novel or non-equilibrium contexts such as invasions, translocations, climate change and evolutionary shifts.

http://max2.ese.u-psud.fr/epc/conservation/PDFs/HIPE/Kearney2009.pdf

Mechanistic niche modelling: combining physiological and spatial data to predict species' ranges.

The fat body plays major roles in the life of insects. It is a dynamic tissue involved in multiple metabolic functions. One of these functions is to store and release energy in response to the energy demands of the insect. Insects store energy reserves in the form of glycogen and triglycerides in the adipocytes, the main fat body cell. Insect adipocytes can store a great amount of lipid reserves as cytoplasmic lipid droplets. Lipid metabolism is essential for growth and reproduction and provides energy needed during extended nonfeeding periods. This review focuses on energy storage and release and summarizes current understanding of the mechanisms underlying these processes in insects.

Insect Fat Body: Energy, Metabolism, and Regulation

Most heat shock proteins (Hsp) function as molecular chaperones that help organisms to cope with stress of both an internal and external nature. Here, we review the recent evidence of the relationship between stress resistance and inducible Hsp expression, including a characterization of factors that induce the heat shock response and a discussion of the associated costs. We report on studies of stress resistance including mild stress, effects of high larval densities, inbreeding and age on Hsp expression, as well as on natural variation in the expression of Hsps. The relationship between Hsps and life history traits is discussed with special emphasis on the ecological and evolutionary relevance of Hsps. It is known that up-regulation of the Hsps is a common cellular response to increased levels of non-native proteins that facilitates correct protein folding/refolding or degradation of non-functional proteins. However, we also suggest that the expression level of Hsp in each species and population is a balance between benefits and costs, i.e. a negative impact on growth, development rate and fertility as a result of overexpression of Hsps. To date, investigations have focused primarily on the Hsp70 family. There is evidence that representatives of this Hsp family and other molecular chaperones play significant roles in relation to stress resistance. Future studies including genomic and proteonomic analyses will increase our understanding of molecular chaperones in stress research.

https://onlinelibrary.wiley.com/doi/pdf/10.1046/j.1461-0248.2003.00528.x

The evolutionary and ecological role of heat shock proteins

Adaptation of Drosophila to temperature extremes: bringing together quantitative and molecular approaches

Summary


1
Biologists have long been concerned with measuring thermal performance curves and limits because of their significance to fitness. Basic experimental design may have a marked effect on the outcome of such measurements, and this is true especially of the experimental rates of temperature change used during assessments of critical thermal limits to activity. To date, the focus of work has almost exclusively been on the effects of rate variation on mean values of the critical limits.

2
If the rate of temperature change used in an experimental trial affects not only the trait mean but also its variance, estimates of heritable variation would also be profoundly affected. Moreover, if the outcomes of acclimation are likewise affected by methodological approach, assessment of beneficial acclimation and other hypotheses might also be compromised.

3
In this article, we determined whether this is the case for critical thermal limits using a population of the model species Drosophila melanogaster and the invasive ant species Linepithema humile.

4
We found that effects of the different rates of temperature change are variable among traits and species. However, in general, different rates of temperature change resulted in different phenotypic variances and different estimates of heritability, presuming that genetic variance remains constant. We also found that different rates resulted in different conclusions regarding the responses of the species to acclimation, especially in the case of L. humile.

5
Although it seems premature to dismiss past generalities concerning interspecific and acclimation-related variation in critical thermal limits, we recommend that conditions during trials be appropriately selected, carefully reported and rigorously controlled.

/pdf/phenotypic-variance-plasticity-and-heritability-estimates-of-4g70274fa8.pdf

Jesper Givskov Sørensen

Papers

The evolutionary and ecological role of heat shock proteins

Adaptation of Drosophila to temperature extremes: bringing together quantitative and molecular approaches

Phenotypic variance, plasticity and heritability estimates of critical thermal limits depend on methodological context

Water loss in insects: An environmental change perspective

Changes in membrane lipid composition following rapid cold hardening in Drosophila melanogaster