Hot answers tagged development
15
There is some evidence that fetal development under zero gravity conditions might be problematic.
Wakayama S, Kawahara Y, Li C, Yamagata K, Yuge L, et al. (2009) Detrimental Effects of Microgravity on Mouse Preimplantation Development In Vitro. PLoS ONE 4(8): e6753. doi:10.1371/journal.pone.0006753
The paper is here.
These authors studied aspects of ...
11
From a certain point of view you could argue that our bodies have an inherently limited lifespan;
Telomeres are extensions to the end of chromosomes that prevent damage or loss of genetic information during cell division. Telomeres are not replaced (in normal cells), which gives rise to a replicative lifespan; the number of times a cell can divide before ...
8
Cell-cell adhesion is a well-regulated mechanism, cells don't just stick together randomly, this interaction is mediated by specific molecules on the cell surfaces. The responsible proteins for that are the Cell Adhesion Molecules (CAMs) like integrins, cadherins and selectins. Which of these CAMs are present on the surface of a cell determines if those ...
5
This is a very interesting question. Many people have researched this topic, and many still are. But regardless, I had never heard of Alan Turing's contributions, so thank you!
First of all, I cannot actually find who first coined the term morphogen. Though people had hypothesized that chemicals could play a critical role in development through much of the ...
5
Many genetic studies in this area have found that variation in serotonin receptors associates with differences in a number of personality traits. That one gene, or a very small number, turns up time and time again for something so complex as human personality makes me a bit suspicious.
Other factors at play:
Family dynamics
Culture and cultural norms
...
4
Cell differentiation, cell fate and cell mapping is an interplay of accessible evolutionary strategies/programmes and responses to dynamic environmental cues such as specialized hormones (e.g. morphogens) and physical parameters and constraints. That is putting it very broadly. It is a complex issue, if L. Wolpert's PLOS assays are any indication. I compiled ...
4
The problem you are looking for is called the "Nature vs nurture" debate. Lots of scientists have written lots of books and papers and done lots of studies on the subject. As you can see, the title of the debate already includes the two main concerning factors: nature (genes) and nurture (environment).
These of course each include a variety of ways in which ...
3
It's old and I can't get access to this issue of the Annals of the New York Academy of Science, but it looks like it has some relevant information. Sifting through the abstracts it seems the vasculature of the fetal liver is completed at around 8 weeks although is still different to the adult vasculature because of the umbilical vein. The growth of the organ ...
2
These two papers[1] [2] argue that bcd is a direct activator of hb, although be aware that this does not rule out downstream events feeding back to further activate hb. (In fact, given the complexity of the embryonic gene network, it is likely that both mechanisms have a role.)
Struhl G, Struhl K, Macdonald PM. 1989. The gradient morphogen bicoid is a ...
2
I would think this is very much still "used." 60 years later, we finally have the first experimental support for it:
In this blog article about this journal piece the authors studied the ridges that form on the roof of mouse mouths. They manipulated the signaling molecules that induce their formation and observed changes in line with Turing's theory. Of ...
2
I asked my professor, and the answer appears to be differences in both the generation and the final product.
Free chromosome fragments are created through irradiation/other damage of the germline in one animal. Through a series of crosses, it is possible to introduce individual fragments (containing a duplication of your gene of interest, as well as a ...
2
@Alexandria Jak/Stat are two families of proteins which mediate signals through phosphotyrosines.
JAK is a tyrosine kinase which binds to cell receptors and STAT is dimerized by JAK action. JAK specificity seems to be your question. A specific JAK protein (e.g. JAK1 or JAK2..) may mediate for different receptors in different cells.
There may be ...
2
Just so that someone answers this question so that the moderators have less work to do:
The fundamental reason why embryos don't get massacred by the maternal immune system is because of the placenta and several of its functions. Three mechanisms are:
1) Secretion of neurokinin B, which is also secreted by parasites to avoid detection of the host.
2) The ...
2
As far as I remember, Fibonacci patterns emerge in plants from hormone gradients. I.e. an apical meristem forms a leaf where the auxin concentration is highest, and already existing leafs lower auxin concentration, leading to some negative feedback.
See e.g.
http://www.sciencedirect.com/science/article/pii/S1360138507000581
or ...
2
Shuster, SM & C Sassaman (1997)
Genetic interaction between male mating strategy and sex ratio in a marine isopod. Nature 388: 373-377
As described in this paper, the chromosomal system of sex determination in Paracerceis sculpta is ZW=females, ZZ=males. Genetic evidence indicates that the morph of a ZZ male is determined by a second locus, Ams ...
1
I found that a search through Google Books was helpful...
While without the excretion of feces, it might seem as if the liver would not be active, but the liver tissue is not only active in development and tissue generation but serves direct physiological function as well.
After initial phases of development, the liver produces fetal red blood cells which ...
1
I would like to add to Lo Sauer's nice answer but give a slightly different perspective.
What you referred to as the "brain" of the cell, is mostly its regulatory program. An abstract way to think about the regulatory program is like a computer, or mathematical function, which gets input (in the form of signal molecules inside and outside the cell) and ...
1
First let me agree with the commenters that your question doesn't really make sense. Nonetheless here's an example that you may find interesting. Arachnocampa are insects that spend almost their entire lives as larva. These larva spin silk trap lines which capture and poison prey. They can only live in windless places (wind will mix up the lines) so to lure ...
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