Molecular brain evolution and overall summary Flashcards
how did molecular brain evolution aid understanding brain evolution
understanding mechanisms of population variation, reconstruct phylogenetic histories, DNA sequencing and analysis (extracting ancient DNA)
where do the genetic difference lie in comparison to chimpanzees (we are 98.7% identical)
Most differences may not lie in parts of DNA that code for protein coding sequences, but on the part of DNA that regulates how our genes operate
what are upregulated genes and what are they involved in in humans
genes that are expressed more (in comparison to chimps), they are involved in synaptic function, plasticity and energy metabolism
which genes in humans have undergone positive selection
FOXp2, ASPM and MCPH1
What are the functions of ASPM and MCPH1
may be involved in production of the brain in utero, cell division and neural precursor and the formation of the upper layers of the cortex. Mutation associated with microcephaly (brain doesn’t fully develop)
what were the result of gabi et al prefrontal gray matter study
volume of gray matter scales as expected to number of neurons, however more numerous than you would find in primate brain
how did changes in size affect changes in shape
Gross-anatomical level: cerebral lobes proportions, white matter tracts.
Cytoarchitecture: area size, neuron number, densit
Cellular level: neuronal structure (e.g., changes in dendritic arborization)
What’s different in the human brain in relation to Grey matter?
Expanded cerebral cortex, Volumetric expansion of temporal lobe (grey and white matter), Human frontal cortex is larger, but not larger than expected for a primate with a human-sized brain, Reorganization of (inferior) parietal cortex (more studies are needed)
what are the main differences about the human brain connectivity wise
direct projections, arcuate fasciculus, superior longitudinal fasciculus
What’s different in the human brain? Molecular
Positive selection for single genes: FOXP2 (also in Neanderthals) ASPM, MCHP1.
Gene upregulation
Accelerate human regions (HAR)
what are HAR (human accelerated regions)
segments of genome conserved in vertebrates but highly differ in humans. enriched for genes involved in transcriptional regulation and brain development. Genes linked with mutations that result in autism and developmental delay
what were the results of the schreiweis et al study (FOXp2)
Foxp2 regulates many learning and memory processes, Could be important in language and learning
results of Gomez et al 2015 study (temporal regions)
Temporal regions seem to be less heritable compared to what we see in chimps, human brain may be more plastic
