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

I. the origin of species by means of natural selection

We redescribe the only previously known species of Myrsidea from bulbuls, M. pycnonoti Eichler. Sixteen new species are described; they and their type hosts are: M. phillipsi ex Pycnonotus goiavier goiavier (Scopoli), M. gieferi ex P. goiavier suluensis Mearns, M. kulpai ex P. flavescens Blyth, M. finlaysoni ex P. finlaysoni Strickland, M. kathleenae ex P. cafer (L.), M. warwicki ex Ixos philippinus (J. R. Forster), M. mcclurei ex Microscelis amaurotis (Temminck), M. zeylanici ex P. zeylanicus (Gmelin), M. plumosi ex P. plumosus Blyth, M. eutiloti ex P. eutilotus (Jardine and Selby), M. adamsae ex P. urostictus (Salvadori), M. ochracei ex Criniger ochraceus F. Moore, M. borbonici ex Hypsipetes borbonicus (J. R. Forster), M. johnsoni ex P. atriceps (Temminck), M. palmai ex C. ochraceus, and M. claytoni ex P. eutilotus. A key is provided for the identification of these 17 species.

A new species

What is ecological speciation

Winter growth and survival of wild individually tagged juvenile Arctic charr (1+ age) from a riverine anadromous stock, were studied in a small ice-covered (� 6 months) ground water brook (temperature � 1 � C) connected to Skibotnelva in subarctic northern Norway. The overall winter survival was estimated to be 68% from late October 2005 to early May 2006. The recaptured charr were not significantly different in initial length or weight compared with the nonrecaptured fish suggesting low size-dependent mortality. The majority (98%) of the recaptured charr showed significant increase in size, with a mean increment of 62% from their initial bodyweight and 12% of the charr parr had more than doubled their weight. The mean specific growth rate was calculated to be slightly lower (0.27) than estimated values from a growth model (� 0.35). In addition, the condition factor increased significantly during the field experiment. These results are the first individual growth data on riverine anadromous Arctic charr parr under natural winter conditions, and indicate that charr can grow relatively fast during periods with low temperature and also that ground water brooks can be good over-wintering habitat for juvenile Arctic charr. These results suggest that the winter period is perhaps a less severe bottleneck than previously recognised for the cold-adapted Arctic charr.

Is the winter period a severe bottleneck of anadromous riverine Arctic charr parr

A population of small-sized Arctic charr living their entire life cycle in deep water was recently found in Lake Skogsfjordvatn, Northern Norway. Their phenotype and life history closely resembles the profundal charr morph in another subarctic Norwegian lake, Fjellfrosvatn. Fjellfrosvatn has one littoral omnivorous and one small profundal benthivorous (PB) charr morph coexisting with brown trout, whereas Skogsfjordvatn has migratory salmon, trout, charr and eel populations in addition to threespined sticklebacks, resident trout and three resident charr morphs of which one is a large piscivorous profundal morph. We predicted that the small profundal charr morph in Skogsfjordvatn would have a similar trophic niche to the PB-morph in Fjellfrosvatn and tested this by using stomach content and stable isotope (δ13C and δ15N) analyses. Profundal benthic invertebrates, mainly chironomid larvae, Pisidium sp. mussels and small crustaceans, dominated the diets, and the δ13C and δ15N values indicated almost identical long-term trophic niches of the PB-morphs in both lakes. The prediction was therefore supported. This seems to indicate that the small profundal Arctic charr morphs in these lakes have evolved in parallel, in nearly identical and stable habitat and dietary niches in spite of likely different ecological interactions within the contrasting fish communities.

Parallel evolution of profundal Arctic charr morphs in two contrasting fish communities

Coregonids constitute one of the most diverse fi sh families in the northern freshwater systems and several species are highly endangered mainly due to anthropogenic pressure. Cost effective and powerful polymerase chain reaction (PCR) microsatellite multiplex assays were established for genetic studies of the population structure, hybridization and conservation status of European whitefi sh (Coregonus lavaretus (L.)) and vendace (C. albula (L.)). An assay containing four PCR multiplexes for co-amplifi cation of 9, 5, 3, and 4 loci was developed for C. lavaretus. Cross-species amplifi cation and rearrangement of the same loci resulted in an assay containing three multiplex reactions of 6, 3, and 4 loci for C. albula. Highly signifi cant pair-wise FST estimates were obtained between C. albula from L. Vaggatem (Norway) and L. Palojärvi (Finland) (FST = 0.301, p < 0.001), between C. lavaretus from L. Skrukkebukta (Norway) and L. Stuorajavri (Norway) (FST = 0.161, p < 0.001), and between morphpairs occurring in the two latter lakes (FST = 0.0135-0.043, p < 0.001). The multiplex assays provided a 100% correct assignment success for discriminating C. lavaretus and C. albula and hence provide a powerful diagnostic tool for the future management of these species.

A diagnostic tool for efficient analysis of the population structure, hybridization and conservation status of European whitefish (Coregonus lavaretus (L.)) and vendace (C. albula (L.))

https://aslopubs.onlinelibrary.wiley.com/doi/pdf/10.1002/lno.10951

Long‐term ecological studies in northern lakes—challenges, experiences, and accomplishments

Reproductive traits differ between intralacustrine Arctic charr morphs. Here, we examine three sympatric lacustrine Arctic charr morphs with respect to fecundity, egg size and spawning time/site to assess reproductive investments and trade-offs, and possible fitness consequences. The littoral omnivore morph (LO-morph) utilizes the upper water for feeding and reproduction and spawn early in October. The large profundal piscivore morph (PP-morph) and the small profundal benthivore morph (PB-morph) utilize the profundal habitat for feeding and reproduction and spawn in December and November, respectively. Females from all morphs were sampled for fecundity and egg-size analysis. There were large differences between the morphs. The PB-morph had the lowest fecundity (mean = 45, SD = 13) and smallest egg size (mean = 3.2 mm, SD = 0.32 mm). In contrast, the PP-morph had the highest fecundity (mean = 859.5, SD = 462) and the largest egg size (mean = 4.5 mm, SD = 0.46 mm), whereas the LO-morph had intermediate fecundity (mean = 580, SD = 225) and egg size (mean = 4.3, SD = 0.24 mm). Fecundity increased with increasing body size within each morph. This was not the case for egg size, which was independent of body sizes within morph. Different adaptations to feeding and habitat utilization have apparently led to a difference in the trade-off between fecundity and egg size among the three different morphs.

The trade-off between fecundity and egg size in a polymorphic population of Arctic charr (Salvelinus alpinus (L.)) in Skogsfjordvatn, subarctic Norway.

Rune Knudsen

Papers

Is the winter period a severe bottleneck of anadromous riverine Arctic charr parr

Parallel evolution of profundal Arctic charr morphs in two contrasting fish communities

A diagnostic tool for efficient analysis of the population structure, hybridization and conservation status of European whitefish (Coregonus lavaretus (L.)) and vendace (C. albula (L.))

Long‐term ecological studies in northern lakes—challenges, experiences, and accomplishments

The trade-off between fecundity and egg size in a polymorphic population of Arctic charr (Salvelinus alpinus (L.)) in Skogsfjordvatn, subarctic Norway.