Timothy H. Webster

The Apolipoprotein E (APOE) Gene Appears Functionally Monomorphic in Chimpanzees (Pan troglodytes)

Background The human apolipoprotein E (APOE) gene is polymorphic, with three primary alleles (E2, E3, E4) that differ at two key non-synonymous sites. These alleles are functionally different in how they bind to lipoproteins, and this genetic variation is associated with phenotypic variation for several medical traits, including cholesterol levels, cardiovascular health, Alzheimer’s disease risk, and longevity. The relative frequencies of these alleles vary across human populations, and the evolution and maintenance of this diversity is much debated. Previous studies comparing human and chimpanzee APOE sequences found that the chimpanzee sequence is most similar to the human E4 allele, although the resulting chimpanzee protein might function like the protein coded for by the human E3 allele. However, these studies have used sequence data from a single chimpanzee and do not consider whether chimpanzees, like humans, show intra-specific and subspecific variation at this locus. Methodology and Principal Findings To examine potential intraspecific variation, we sequenced the APOE gene of 32 chimpanzees. This sample included 20 captive individuals representing the western subspecies (P. troglodytes verus) and 12 wild individuals representing the eastern subspecies (P. t. schweinfurthii). Variation in our resulting sequences was limited to one non-coding, intronic SNP, which showed fixed differences between the two subspecies. We also compared APOE sequences for all available ape genera and fossil hominins. The bonobo APOE protein is identical to that of the chimpanzee, and the Denisovan APOE exhibits all four human-specific, non-synonymous changes and appears functionally similar to the human E4 allele. Conclusions We found no coding variation within and between chimpanzee populations, suggesting that the maintenance of functionally diverse APOE polymorphisms is a unique feature of human evolution.

Selective insectivory at Toro-Semliki, Uganda: Comparative analyses suggest no ‘savanna’ chimpanzee pattern

Chimpanzee (Pan troglodytes) insectivory across Africa is ubiquitous. Insects provide a significant nutritional payoff and may be important for chimpanzees in dry, open habitats with narrow diets. We tested this hypothesis at Semliki, Uganda, a long-term dry study site. We evaluated prospects for insectivory by measuring insect abundance along de novo transects and trails, monitoring social insect colonies, and surveying available raw materials for elementary technology. We determined the frequency and nature of insectivory through behavioral observation and fecal analysis. We then compared our results with those from 15 other long-term chimpanzee study sites using a cluster analysis. We found that Semliki chimpanzees are one of the most insectivorous populations studied to date in terms of frequency of consumption, but they are very selective in their insectivory, regularly consuming only weaver ants (Oecophylla longinoda) and honey and bees from hives of Apis mellifera. This selectivity obtains despite having a full range of typical prey species available in harvestable quantities. We suggest that Semliki chimpanzees may face ecological time constraints and therefore bias their predation toward prey taxa that can be quickly consumed. Geographical proximity correlated with the results of the cluster analysis, while rainfall, a relatively gross measure of environment, did not. Because broad taxonomic groups of insects were used in analyses, prey availability was unlikely to have a strong effect on this pattern. Instead, we suggest that transmission of cultural knowledge may play a role in determining chimpanzee prey selection across Africa. Further study is needed to test these hypotheses.

Resource seasonality and reproduction predict fission–fusion dynamics in black‐and‐white ruffed lemurs (Varecia variegata)

Ruffed lemurs (genus Varecia) are often described as having a flexible social organization, such that both cohesive (low fission–fusion dynamics) and fluid (high fission–fusion dynamics) grouping patterns have been observed. In ruffed lemur communities with high fission–fusion dynamics, group members vary in their temporal and spatial dispersion throughout a communally defended territory. These patterns have been likened to those observed in several haplorrhine species that exhibit the most fluid types of fission–fusion social organization (e.g., Pan and Ateles). To substantiate and further refine these claims, we describe the fission–fusion dynamics of a black‐and‐white ruffed lemur (Varecia variegata) community at Mangevo, an undisturbed primary rainforest site in Ranomafana National Park, Madagascar. We collected instantaneous group scan samples from August 2007–December 2008 (4,044 observation hours) to study and characterize patterns of subgroup size, composition, cohesion, and social association. In 16 consecutive months, we never found all members of the community together. In fact, individuals spent nearly half of their time alone. Subgroups were small, cohesive, and typically of mixed‐sex composition. Mixed‐sex subgroups were significantly larger, less cohesive, and more common than either male‐only or female‐only subgroups. Subgroup dynamics were related to shifts in climate, phenology of preferred fruit species, and female reproductive state. On average, association indices were low. Males and females were equally gregarious; however, adult male–male associations were significantly weaker than any other association type. Results presented herein document striking differences in fission–fusion dynamics between black‐and‐white ruffed lemurs and haplorrhines, while also demonstrating many broad‐scale similarities to haplorrhine taxa that possess the most fluid fission–fusion societies. Am. J. Primatol. 78:256–279, 2016.

Chimpanzees at Semliki Ignore Oil Palms

on galagos has (thus far) been observed only in a single immigrant matriline of the Kasakela community. Red colobus, the prey of choice for many chimpanzee populations in East Africa, are not present at either Assirik or Fongoli where predation on galagos appears to be more common than elsewhere. McGrew

East Asia Institutionalizes: China, Japan and the Vogue for Free Trade

In the past decade, East Asia has taken steps to increase regional integration. This paper examines the vogue for Free Trade Agreements (FTAs) currently raging in China and Japan. After mapping the regional links that knit East Asia together during the 1990s and 2000s, the focus then shifts to the specific trade agreements that China and Japan have signed. Both countries exhibit a particular FTA “style;” Japan has adopted a more orthodox and comprehensive approach to its treaties, while China has shown greater flexibility and gradualism when dealing with FTA partners. It is still unclear whether these efforts will lead to a region-wide FTA, or a continued crisscrossing of bilateral arrangements. In either case, Chinas eagerness to adapt to partner country expectations likely gives it an edge in becoming the regional hub of East Asia