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The cells differentiation during post fertilization period is govern by a set of regulatory genes called Homeotic genes.These are genes that "select" the identity of entire segments or structures in the bodies of developing organisms. These gene encodes a transcription factor that is expressed in a specific region of the organism starting in its early ...


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Epigenetic marks are reversible (you might be aware of induced pluripotent cells). Many animals can regenerate organs with high tissue complexity (such as a limb) and this involves de-differentiation in some species (Sandoval-Guzman et al., 2014). Even otherwise, cells can respond to extracellular/environmental cues to modify their epigenetic state (for e.g. ...


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Spermatogenesis (Beginning to end): 64 +- 8 days (range 42 to 76) There is considerable individual variation. This includes time in epididymis. Amann 2008 argue for 74 days based on early study by Clermont 1972. Also argue that biopsies are still needed on top of radiolabelling. Substages: Calculated from Amann 2008, Figure 1 using percent time in 16 ...


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Wikipedia has a page listing cell types which classifies their origin as endodermal or ectodermal. I haven't been able to find a source for a complete lineage of all cell types, and I have gained the impression that there is no complete picture, except in some specific cases such as the haemopoietic lineage. Here is a TEDX talk by a researcher in the ...


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Looking at the paper itself, we find that they prepared the stem cells to have myogenic (muscle-specific) properties. They first injected stem cells into the irradiated (which kills muscle stem cells) muscles of immune-deficient mice. This resulted in tumor growth (teratoma - a stem cell derived tumor, where different kinds of tissues are spontaneously ...


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If you are referring to cells that are differentiated in adults: Some somatic cells in multi-cellular organisms are post-mitotic, that is, the cells cannot divide, or said in other words, they don't enter in S phase. This cells are said to be in G0 phase, because they keep synthesizing proteins but the won't replicate their DNA. Another thing we could say ...


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This has been studied this in Drosophila, and a lot of development hinges on where the cell is in the body. An initial asymmetry of mRNA in the pre-fertilized ovum leads to the establishment of the anterior-posterior axis (which end is the head, which is the tail) So cells are told what to develop into based on what mRNA signals they receive which depends ...


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Activation and deactivation of different genes commands the process of cell differentiation. Gene expression responsible for cell differentiation is controlled by intrinsic and extrinsic signals. This regulated signalling from inside and outside the cell is responsible for embryonic development. Environment around the cell, such as small molecules, ...


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If all cells have identical genomes and, therefore, identical transcription factors Important comment: all cells do indeed have identical genomes, and all cells are therefore equipped with DNA that codes for transcription factors, but that does not mean that all cells have the same state of the genome. It is well understood that different cell types have ...


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There is a mechanism in T and B cells called allelic exclusion. This means that most of the times only a single allele is used by building the light chain and the other is excluded. Incomplete allelic exclusion may contribute to auto-immune diseases, because cells using two different light chains can potentially recognize both pathogens and healthy human ...


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Pathway analysis can be a little tricky. Because pathway enrichment is estimated from the enrichment of genes (or miRNA or what have you) that participate in overlapping pathways, certain pathways often show up for reasons that may have little to do with your experiment. Cell cycle related pathways, in particular, come up a lot, since so many genes are "cell ...


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Yes differentiation is primarily about using only a portion of the genome as you pointed out. However, differentiated cells possess a kind of "memory" which enables the daughter cells to continue the usage of the same set of genes. This "memory" is enabled by epigenetic mechanisms which leave inheritable "marks" on the DNA such as methylation (I won't ...


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B. Higher surface to volume ratio allows better interface with environment. C. To increase surface area the cell can form processes such as microvilli.


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As already said in a comment: I would guess that ecological divergence emphasizes on the process of speciation by niche differentiation while ecological differentiation emphasizes on the process of niche differentiation due to overlapping niche of non-necessarily closely related species. But looking to some articles, it seems that they use both term without ...


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