Beyond the DNA sequence difference between humans and closely related apes, there are large differences in the environments that these species experience. One prominent example for this is diet. The human diet diverges from those of other primates in various aspects, such as having a high calorie and protein content, as well as being cooked. Here, we used a laboratory mouse model to identify gene expression differences related to dietary differences.
Human and chimpanzee gene expression differences replicated in mice fed different diets.
Sex, Age
View SamplesBeyond the DNA sequence difference between humans and closely related apes, there are large differences in the environments that these species experience. One prominent example for this is diet. The human diet diverges from those of other primates in various aspects, such as having a high calorie and protein content, as well as being cooked. Here, we used a laboratory mouse model to identify gene expression differences related to dietary differences.
Human and chimpanzee gene expression differences replicated in mice fed different diets.
Sex, Age
View SamplesMicroarray technologies allow the identification of large numbers of expression differences within and between species. Although environmental and physiological stimuli are clearly responsible for changes in the expression levels of many genes, it is not known whether the majority of changes of gene expression fixed during evolution between species and between various tissues within a species are caused by Darwinian selection or by stochastic processes. We find the following: (1) expression differences between species accumulate approximately linearly with time; (2) gene expression variation among individuals within a species correlates positively with expression divergence between species; (3) rates of expression divergence between species do not differ significantly between intact genes and expressed pseudogenes; (4) expression differences between brain regions within a species have accumulated approximately linearly with time since these regions emerged during evolution. These results suggest that the majority of expression differences observed between species are selectively neutral or nearly neutral and likely to be of little or no functional significance. Therefore, the identification of gene expression differences between species fixed by selection should be based on null hypotheses assuming functional neutrality. Furthermore, it may be possible to apply a molecular clock based on expression differences to infer the evolutionary history of tissues.
A neutral model of transcriptome evolution.
Sex, Age, Specimen part, Disease, Disease stage
View SamplesThis SuperSeries is composed of the SubSeries listed below.
MicroRNA-driven developmental remodeling in the brain distinguishes humans from other primates.
Sex, Age, Specimen part
View SamplesWe investigated molecular changes during human, chimpanzee, and rhesus macaque postnatal brain development at the transcriptome, proteome, and metabolome levels in two brain regions: the prefrontal cortex (PFC) that is involved in several human-specific cognitive processes, and the cerebellar cortex (CBC) that may be functionally more conserved. We find a nearly three-fold excess of human-specific gene expression changes in PFC compared to CBC. The most prominent human-specific mRNA expression pattern in the PFC is a developmental delay of approximately 5 years in the expression of genes associated with learning and memory, such as synaptic transmission and long-term potentiation. This pattern is supported by correlated changes in concentrations of proteins and the respective neurotransmitters and its magnitude is beyond the shift expected from the life-histories of the species. Mechanistically, it might be driven by change in timing of expression of four or more transcription factors. We speculate that delayed synaptic maturation in PFC may play a role in the emergence of human-specific cognitive abilities.
MicroRNA-driven developmental remodeling in the brain distinguishes humans from other primates.
Sex, Age, Specimen part
View SamplesWe investigated molecular changes during human, chimpanzee, and rhesus macaque postnatal brain development at the transcriptome, proteome, and metabolome levels in two brain regions: the prefrontal cortex (PFC) that is involved in several human-specific cognitive processes, and the cerebellar cortex (CBC) that may be functionally more conserved. We find a nearly three-fold excess of human-specific gene expression changes in PFC compared to CBC. The most prominent human-specific mRNA expression pattern in the PFC is a developmental delay of approximately 5 years in the expression of genes associated with learning and memory, such as synaptic transmission and long-term potentiation. This pattern is supported by correlated changes in concentrations of proteins and the respective neurotransmitters and its magnitude is beyond the shift expected from the life-histories of the species. Mechanistically, it might be driven by change in timing of expression of four or more transcription factors. We speculate that delayed synaptic maturation in PFC may play a role in the emergence of human-specific cognitive abilities.
MicroRNA-driven developmental remodeling in the brain distinguishes humans from other primates.
Sex, Age, Specimen part
View SamplesNeurons and endothelial cells were identified by immunohistochemistry in human brains, isolated by laser-capture-microdissection and used to find genes preferentially expressed in the two cell types.
Evolution of neuronal and endothelial transcriptomes in primates.
Sex, Specimen part
View SamplesIn order to assess the impact of three rounds of linear amplification on the technical reproducibility of gene expression measurements, we performed twelve microarray experiments. We analysed mouse RNA from cortex, cerebellum and liver from one individual. One RNA sample of 5g from each of the three different tissues was processed according to the standard Affymetrix protocol and hybridized onto mouse gene expression arrays MG_U74Av2. Three additional samples from each tissue of 1ng were processed according to a modified procedure that involves three linear amplifications before hybridization onto the microarray chips.
Evolution of neuronal and endothelial transcriptomes in primates.
Specimen part
View SamplesThis SuperSeries is composed of the SubSeries listed below.
Extension of cortical synaptic development distinguishes humans from chimpanzees and macaques.
Sex, Age, Specimen part
View SamplesWe search for developmental changes specific to humans by examining gene expression profiles in the human, chimpanzee and rhesus macaque prefrontal and cerebellar cortex. In both brain regions, developmental patterns were more evolved in humans than in chimpanzees. To distinguish whether the human specific developmental pattern represent novel human-specific developmental patterns or a shift in the timing of the existing patterns, we measured mRNA expression patterns in macaque brains from prenatal to neonatal. Our results show that the major human-specific developmental patterns identified in the PFC reflects an extreme shift in timing of synaptic development.
Extension of cortical synaptic development distinguishes humans from chimpanzees and macaques.
Sex, Age, Specimen part
View Samples