Date Palm DNA Mini-Preparation without Liquid Nitrogen

We have developed a new mini-procedure for isolation of total cellular DNA from date palm (Phoenix dactylifera L.). The procedure, which does not use liquid nitrogen, has proved useful due to temporary disruptions in supplies of liquid nitrogen that occur in countries where date palm trees are cultivated. DNA suitable for RFLP and PCR analyses is obtained.     

Evolution of sprouting versus seeding inAspalathus linearis

We have tested the hypothesis that reseeding is a plesiomorphic character state and that sprouting is a derived state inAspalathus linearis, and that the latter is an adaptation to ensure fire-survival in a fireprone environment. Samples of five seeder and four sprouter populations of A.linearis were examined by horizontal starch gel electrophoresis to assess the amount of genetic differentiation within and between sprouting and seeding populations, and to determine the extent of gene flow between the populations. Leaf extracts were surveyed for ten enzymes and gene products revealed genetic variation at 13 (76%) of 17 protein coding loci. Allele frequency differences were found between sprouting and seeding populations and genetic distance values show that the sprouters are grouped separate from the seeders, thus providing support for the morphological data on which the above mentioned hypothesis is based. It is evident that evolution operates at the population level inA. linearis.     

Dominance,Coloration, and Social and Sexual Behavior in Male Drills <Emphasis Type="Italic">Mandrillus leucophaeus</Emphasis>

Sexual selection has driven the evolution and elaboration of a wide variety of displays and ornaments in male nonhuman primates, including capes, cheek flanges, and sexual coloration. Among the most sexually dimorphic of all primates is the drill (Mandrillus leucophaeus), the males of which can be 3 times the mass of females, possess large canines, and exhibit extremely bright sexual skin coloration. However, the function of male coloration in this species has never been examined. Here, we present data on male color (measured objectively using digital photography), dominance rank, measures of male-female association, and key sexual behaviors, of adult male drills (n = 17) living in four semi free-ranging enclosures at the Drill Rehabilitation and Breeding Center in Nigeria. We test the hypothesis that male coloration is a badge of status, indicating dominance rank, and the hypothesis that male coloration attracts females. We found that male coloration did indicate rank, and that high ranking, strongly colored males were more likely to associate with adult females, and more specifically with fully tumescent females. These males also engaged in more sexual activity. However, measures of male-female association and sexual behaviors were not related to male color once rank had been taken into consideration; i.e., for males of a given rank, females did not prefer those that were more colorful. We discuss the results in light of what is known about the wild drill social system, in which unfamiliar individuals may come together in “supergroups,” and in which quality indicators of competitive ability may be particularly important.     

Polypyrimidine Tract Binding Protein Prevents Activity of an Intronic Regulatory Element That Promotes Usage of a Composite 3��-Terminal Exon

Alternative splicing of 3′-terminal exons plays a critical role in gene expression by producing mRNA with distinct 3′-untranslated regions that regulate their fate and their expression. The Xenopus α-tropomyosin pre-mRNA possesses a composite internal/3′-terminal exon (exon 9A9′) that is differentially processed depending on the embryonic tissue. Exon 9A9′ is repressed in non-muscle tissue by the polypyrimidine tract binding protein, whereas it is selected as a 3′-terminal or internal exon in myotomal cells and adult striated muscles, respectively. We report here the identification of an intronic regulatory element, designated the upstream terminal exon enhancer (UTE), that is required for the specific usage of exon 9A9′ as a 3′-terminal exon in the myotome. We demonstrate that polypyrimidine tract binding protein prevents the activity of UTE in non-muscle cells, whereas a subclass of serine/arginine rich (SR) proteins promotes the selection of exon 9A9′ in a UTE-dependent way. Morpholino-targeted blocking of UTE in the embryo strongly reduced the inclusion of exon 9A9′ as a 3′-terminal exon in the endogenous mRNA, demonstrating the function of UTE under physiological circumstances. This strategy allowed us to reveal a splicing pathway that generates a mRNA with no in frame stop codon and whose steady-state level is translation-dependent. This result suggests that a non-stop decay mechanism participates in the strict control of the 3′-end processing of the α-tropomyosin pre-mRNA.     

Predicted impact of exotic vines on an endangered ecological community under future climate change

Potential interactions between climate change and exotic plant invasions may affect areas of high conservation value, such as land set aside for the protection of endangered species or ecological communities. We investigated this issue in eastern Australia using species distribution models for five exotic vines under climate regimes for 2020 and 2050. We examined how projected changes in the distribution of climatically suitable habitat may coincide with the remaining remnants of an endangered ecological community—littoral rainforests—in this region. The number of known infestations of each weed in tropical, subtropical and temperate areas was used to assess the likelihood of further expansion into areas projected to provide suitable habitat under future conditions. Littoral rainforest reserves were consistently predicted to provide bioclimatically suitable habitat for the five vines examined under both current and future climate scenarios. We explore the consequences and potential strategies for managing exotic plant invasions in these protected areas in the coming decades.     

Modeling the Biogeography of Fossil Baboons

We use a model of modern baboon socio-ecology to explore the behavioral ecology and biogeography of the extinct Plio-Pleistocene baboons (genera Parapapio, Gorgopithecus, Dinopithecus, and Papio). The model is based on the way climate affects the baboons’ time budgets, and focuses on intersite variability in behavior rather than on species-typical patterns of behavior, as most previous approaches have done. We use climate estimates for individual fossil sites based on matching modern habitats using faunal profiles and estimates of individual species’ body masses given in the literature. The model allows us to examine the minimum and maximum sizes of groups that individual species would have been able to support at particular localities, and hence the biogeography of a species on a continental scale. In doing so, the model allows us to examine which variables are most responsible for limiting a species’ ecological and biogeographic flexibility, and through this to explore a species’ capacity for coping with climate change. Feeding time is identified as the main constraint. In general, large-bodied species would have had more difficulty surviving in as wide a range of habitats as smaller-bodied species, and this may explain the limited geographical distribution of large-bodied baboons such as Gorgopithecus and Dinopithecus.     

The total burden of rare,non-synonymous exome genetic variants is not associated with childhood or late-life cognitive ability

Human cognitive ability shows consistent, positive associations with fitness components across the life-course. Underlying genetic variation should therefore be depleted by selection, which is not observed. Genetic variation in general cognitive ability (intelligence) could be maintained by a mutation–selection balance, with rare variants contributing to its genetic architecture. This study examines the association between the total number of rare stop-gain/loss, splice and missense exonic variants and cognitive ability in childhood and old age in the same individuals. Exome array data were obtained in the Lothian Birth Cohorts of 1921 and 1936 (combined N = 1596). General cognitive ability was assessed at age 11 years and in late life (79 and 70 years, respectively) and was modelled against the total number of stop-gain/loss, splice, and missense exonic variants, with minor allele frequency less than or equal to 0.01, using linear regression adjusted for age and sex. In both cohorts and in both the childhood and late-life models, there were no significant associations between rare variant burden in the exome and cognitive ability that survived correction for multiple testing. Contrary to our a priori hypothesis, we observed no evidence for an association between the total number of rare exonic variants and either childhood cognitive ability or late-life cognitive ability.