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

Preface to the Princeton Landmarks in Biology Edition vii Preface xi Symbols Used xiii 1. The Importance of Islands 3 2. Area and Number of Speicies 8 3. Further Explanations of the Area-Diversity Pattern 19 4. The Strategy of Colonization 68 5. Invasibility and the Variable Niche 94 6. Stepping Stones and Biotic Exchange 123 7. Evolutionary Changes Following Colonization 145 8. Prospect 181 Glossary 185 References 193 Index 201

The Theory of Island Biogeography

Statistical method for testing the neutral mutation hypothesis by DNA polymorphism.

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

Mesquite: a modular system for evolutionary analysis. Version 2.6

Aspects of birdsong complexity, such as the number of distinct notes in a song, commonly increase along latitudinal gradients, a pattern for which at least 10 explanations have been suggested In two Himalayan warblers, songs are more complex in the northwest than in the southeast In Grey-hooded Warbler Phylloscopus xanthoschistos, high complexity results from increased note diversity within song types, sung across a higher bandwidth In Blyth's Leaf Warbler Phylloscopus reguloides, high complexity is a consequence of increased variation between song types The hypothesis with strongest support is that songs evolved to be more complex in species-poor, demonstrably less noisy environments We consider geographical variation to be an outcome of sexual selection favouring complexity across environments, where detection of the signal varies Sexual selection favouring complexity may be resolved in different ways, because complexity has multiple features (repertoire size, song switching, etc) We argue this has led to the great diversity in song that we have documented among five Phylloscopus species

Causes of the latitudinal gradient in birdsong complexity assessed from geographical variation within two Himalayan warbler species

Introduction Nearly all speciation events in animals seem to involve spatial separation of populations, at least in the initial stages of divergence, and we have few compelling examples of sympatric speciation (Mayr 1947; Coyne & Orr 2004). Given the requirement of geographical isolation, following Mayr (1947), we consider three steps that limit the rate at which new species form. First, gene flow between populations must be restricted. Second, populations diverge in various traits that generate reproductive isolation. Third, populations must expand ranges. This third stage is essential, for without range expansions, newly produced species would remain geographical replacements of one another, severely limiting the total number of species that can be produced from a common ancestor. Stage 2, that is the generation of reproductive isolation, is usually taken to be synonymous with speciation (Coyne & Orr 2004). Ecological conditions experienced by different taxa can drive and accelerate the rate of attainment of reproductive isolation (‘ecological speciation’, Schluter 2001; Rundle & Nosil 2005), thereby accelerating speciation. This has been the focus of much recent study and is one of the main topics considered in this volume. However, ecological influences on any of the three stages – not just the acquisition of reproductive isolation – can limit the rate at which new species form (Mayr 1947). In this chapter, we first summarize various ecological and nonecological factors that may limit each of the three stages of speciation. Then we ask if speciation events are temporally distributed in some way, which is predicted frommany ecological models of speciation. In particular, ecological factors may promote speciation more rapidly early in adaptive radiation rather than later, because range expansion is easier at this time due to fewer competitors (Mayr 1942, 1947), or because reproductive isolation evolves more quickly (Rice & Hostert 1993; Schluter 2000, 2001). Gavrilets and Vose (2005, this volume) also find a burst of speciation early in adaptive radiation in their simulations, partly because as species evolve to become specialists in one particular niche, they can

Speciation and Patterns of Diversity: Ecological influences on the temporal pattern of speciation

1. We studied fat storage in a population of greenish leaf warblers (Phylloscopus trochiloides) in southern India over four winters (1993–97). This species breeds in temperate regions and overwinters in India from October to April.



2. Diurnal variation in fat scores was comparable to that seen among temperate wintering passerines. Seasonal variation was slight, except for premigratory fattening. There was significant annual variation: in drier winters, which were also winters of low food supplies, fat scores were higher.



3. Energy metabolized overnight is unlikely to vary across winters, and annual variation in fat scores is considered a response to uncertainty of food intake on a given day. Fat scores varied inversely with short-term rainfall, which drives the abundance of arthropod prey.



4. Annual variation in fat scores was not accompanied by changes in total body mass. This suggests that protein reserves were being compromised by increased fat deposition in dry years and offers an explanation for the observed delay in moult during drier winters. These results suggest that strategies for maximizing short-term probability of survival translate into future fitness costs, and may shape long-term life-history strategies through simple physiological processes.

Annual variation in fat storage by a migrant warbler overwintering in the Indian tropics

Unrelated passerine birds often join together while mobbing, a widespread antipredator behavior during which birds harass a predator. Although previous analyses concluded that mobbing could not have evolved via reciprocity, Krams and colleagues' field experiments show that birds preferentially join mobs with neighbors that have aided them previously, suggesting that these birds utilize reciprocity-based strategies involving individual recognition and recollection of previous interactions with others. This implies a level of sophistication in bird communities greater than had previously been realized.

https://www.cell.com/trends/ecology-evolution/pdf/S0169-5347(08)00199-7.pdf

Reciprocal cooperation in avian mobbing: playing nice pays

Some signals vary greatly, whereas others are remarkably similar across distantly related species. Here, we ask how the suite of receivers and information communicated correlates with signal evolution by comparing 2 different signals across the same set of species. Within the Old World leaf warblers (Phylloscopidae), each species utters 2 acoustically distinct alarm calls. The first, termed a "general" call, is used in interactions with conspecifics as a well as during confrontations with predators and nest-parasitic cuckoos. The second, termed a "rasp" call, is primarily used in the presence of nest-parasitic cuckoos. The rasp call precedes aggressive attacks on cuckoos and attracts surrounding heterospecifics that are also potential hosts. The general call attracts a wide range of species threatened by predators, including those that are not cuckoo hosts. Acoustic features of general calls evolve >5x faster than rasp calls. We argue that rasp calls show strong stasis because they have a restricted function as aggressive antiparasite signals, whereas multiple contexts and receivers have promoted divergence in general calls. These results support the idea that variation in the suite of receivers is a powerful force affecting signal evolution.

/pdf/rates-of-signal-evolution-are-associated-with-the-nature-of-1pgf094tx7.pdf

Trevor D. Price

Papers

Causes of the latitudinal gradient in birdsong complexity assessed from geographical variation within two Himalayan warbler species

Speciation and Patterns of Diversity: Ecological influences on the temporal pattern of speciation

Annual variation in fat storage by a migrant warbler overwintering in the Indian tropics

Reciprocal cooperation in avian mobbing: playing nice pays

Rates of signal evolution are associated with the nature of interspecific communication