Chimpanzee enterotype variation is just like ours.
Microbes inhabiting the human gastrointestinal tract tend to adopt one of three characteristic community structures, called ‘enterotypes’, each of which is overrepresented by a distinct set of bacterial genera. Here we report that the gut microbiotae of chimpanzees also assort into enterotypes and that these chimpanzee enterotypes are compositionally analogous to those of humans. Through the analysis of longitudinal samples, we show that the microbial signatures of the enterotypes are stable over time, but that individual hosts switch between enterotypes over periods longer than a year. These results support the hypothesis that enterotypic variation was present in populations of great apes before the divergence of humans and chimpanzees.
|Fig. 1 (a) Left chimpanzee enterotypes, right human ones|
High altitude adaptions in Ethiopia
Although hypoxia is a major stress on physiological processes, several human
populations have survived for millennia at high altitudes, suggesting that they
have adapted to hypoxic conditions. This hypothesis was recently corroborated
by studies of Tibetan highlanders, which showed that polymorphisms in candidate
genes show signatures of natural selection as well as well-replicated
association signals for variation in hemoglobin levels. We extended genomic
analysis to two Ethiopian ethnic groups: Amhara and Oromo. For each ethnic
group, we sampled low and high altitude residents, thus allowing genetic and
phenotypic comparisons across altitudes and across ethnic groups. Genome-wide
SNP genotype data were collected in these samples by using Illumina arrays. We
find that variants associated with hemoglobin variation among Tibetans or other
variants at the same loci do not influence the trait in Ethiopians. However, in
the Amhara, SNP rs10803083 is associated with hemoglobin levels at genome-wide
levels of significance. No significant genotype association was observed for
oxygen saturation levels in either ethnic group. Approaches based on allele
frequency divergence did not detect outliers in candidate hypoxia genes, but
the most differentiated variants between high- and lowlanders have a clear role
in pathogen defense. Interestingly, a significant excess of allele frequency
divergence was consistently detected for genes involved in cell cycle control,
DNA damage and repair, thus pointing to new pathways for high altitude
adaptations. Finally, a comparison of CpG methylation levels between high- and
lowlanders found several significant signals at individual genes in the Oromo.
Pig and boar genomes and evolutionary history
For 10,000 years pigs and humans have shared a close and complex relationship. From domestication to modern breeding practices, humans have shaped the genomes of domestic pigs. Here we present the assembly and analysis of the genome sequence of a female domestic Duroc pig (Sus scrofa) and a comparison with the genomes of wild and domestic pigs from Europe and Asia. Wild pigs emerged in South East Asia and subsequently spread across Eurasia. Our results reveal a deep phylogenetic split between European and Asian wild boars ~1 million years ago, and a selective sweep analysis indicates selection on genes involved in RNA processing and regulation. Genes associated with immune response and olfaction exhibit fast evolution. Pigs have the largest repertoire of functional olfactory receptor genes, reflecting the importance of smell in this scavenging animal. The pig genome sequence provides an important resource for further improvements of this important livestock species, and our identification of many putative disease-causing variants extends the potential of the pig as a biomedical model.
|Fig. 3 – reconstructed/estimated demographic history of boars|
Less obvious strategies in long term evolutionary co-adaption
One strategy for winning a coevolutionary struggle is to evolve rapidly. Most of the literature on host-pathogen coevolution focuses on this phenomenon, and looks for consequent evidence of coevolutionary arms races. An alternative strategy, less often considered in the literature, is to deter rapid evolutionary change by the opponent. To study how this can be done, we construct an evolutionary game between a controller that must process information, and an adversary that can tamper with this information processing. In this game, a species can foil its antagonist by processing information in a way that is hard for the antagonist to manipulate. We show that the structure of the information processing system induces a fitness landscape on which the adversary population evolves. Complex processing logic can carve long, deep fitness valleys that slow adaptive evolution in the adversary population. We suggest that this type of defensive complexity on the part of the vertebrate adaptive immune system may be an important element of coevolutionary dynamics between pathogens and their vertebrate hosts. Furthermore, we cite evidence that the immune control logic is phylogenetically conserved in mammalian lineages. Thus our model of defensive complexity suggests a new hypothesis for the lower rates of evolution for immune control logic compared to other immune structures.
Genetics and psychology in relation to heroin use and abuse
BackgroundThe interaction of the association of dopamine genes, impulsivity and childhood trauma with substance abuse remains unclear.
clarify the impacts and the interactions of the Catechol
-O-methyltransferase (COMT) gene, impulsivity and childhood trauma on
the age of onset of heroin use among heroin dependent patients in China.
male and 248 female inpatients who meet DSM-IV criteria of heroin
dependence were enrolled. Impulsivity and childhood trauma were measured
using BIS-11 (Barratt Impulsiveness Scale-11) and ETISR-SF (Early
Trauma Inventory Self Report-Short Form). The single nucleotide
polymorphism (SNP) rs737866 on the COMT gene-which has previously been
associated with heroin abuse, was genotyped using a DNA sequence
detection system. Structural equations model was used to assess the
interaction paths between these factors and the age of onset of heroin
test indicated the individuals with TT allele have earlier age of onset
of heroin use than those with CT or CC allele. In the correlation
analysis, the severity of childhood trauma was positively correlated to
impulsive score, but both of them were negatively related to the age of
onset of heroin use. In structure equation model, both the COMT gene and
childhood trauma had impacts on the age of onset of heroin use directly
or via impulsive personality.
findings indicated that the COMT gene, impulsive personality traits and
childhood trauma experience were interacted to impact the age of onset
of heroin use, which play a critical role in the development of heroin
dependence. The impact of environmental factor was greater than the COMT
gene in the development of heroin dependence.