The experiments showed that the human and chimpanzee brain organoids were remarkably similar in many ways including in the mix of cell types and in how these cells were arranged. have now analysed brain organoids grown from reprogrammed human, chimpanzee and orangutan cells. ![]() Mora-Bermúdez, Badsha, Kanton, Camp et al. Recently, researchers have been able to use these reprogrammed cells to make tissue that resembles the brain in petri dishes, known as brain organoids. Under the right conditions, cells collected from adult humans and other animals can be reprogrammed to behave like brain stem cells. To study the earliest stages of brain development, researchers often use human brain cells grown in the laboratory. ![]() How these species differences arise is not clear, but it likely occurs in the earliest phases of development when brain stem and progenitor cells divide and give rise to cerebral cortex cells in the growing brain. Networks of brain cells in the cerebral cortex also behave differently in the two species. Moreover, a part of the brain called the cerebral cortex – which plays a key role in memory, attention, awareness and thought – contains twice as many cells in humans as the same region in chimpanzees. The human brain is about three times as big as the brain of our closest living relative, the chimpanzee. These subtle differences in cortical progenitors between humans and chimpanzees may have consequences for human neocortex evolution. Consistent with this, the small set of genes more highly expressed in human apical progenitors points to increased proliferative capacity, and the proportion of neurogenic basal progenitors is lower in humans. Notably, however, live imaging of apical progenitor mitosis uncovered a lengthening of prometaphase-metaphase in humans compared to chimpanzees that is specific to proliferating progenitors and not observed in non-neural cells. We find that the cytoarchitecture, cell type composition, and neurogenic gene expression programs of humans and chimpanzees are remarkably similar. Here, we have searched for such differences by analysing cerebral organoids from human and chimpanzees using immunohistofluorescence, live imaging, and single-cell transcriptomics. This expansion is thought to primarily reflect differences in proliferation versus differentiation of neural progenitors during cortical development. (That may or may not matter for what you are trying to do with this information.Human neocortex expansion likely contributed to the remarkable cognitive abilities of humans. In other words, male chimpanzees might pull harder at least in part because they are more motivated than females in this particular setting, rather than because of intrinsic differences in strength. (I found that "chimpanzee strength" gave better results as a search term than terms including "sexual dimorphism", which tended to be swamped by more general discussions of the evolution of dimorphism in notes in a comment thatĮxtreme caution is needed in interpreting these results for Chimp sexual dimorphism, quite apart from the very low number of individuals, there is a significant problem with these measurements - as the paper itself notes "The inability to control nonhuman primates' motivation hinders the exact quantification of the muscular strength difference between humans and nonhuman primates, even in a highly controlled experimental setup." This problem equally applies to male/female differences. give a few other references, you could follow those as well and see what you come up with. The ratios of max pull to weight for males were 3.44 and 3.49, for females were 2.9, 3.14, and 3.25 (one of the males was quite small. In fact, the Excel spreadsheet given in supplementary materials shows there were two males and three females, tested in three sessions in each session weight and pull strength were listed. Which shows pulling strength normalized by individual body weight, with circles for females and diamonds for males. PloS Biology 2014 "Exceptional evolutionary divergence of human muscle and brain metabolomes parallels human cognitive and physical uniqueness" where I found this figure: PNAS 2017 "Chimpanzee Super Strength and Human Skeletal Muscle Evolution" ![]() I searched for "chimpanzee strength" on PubMed and followed links from
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |