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19

Welcome to Biology.SE. Am I remembering this incorrectly? Yes, you're remembering well. I think you're talking about slime molds. You'll find more information on the wiki page Is this the video you saw? These images are pretty cool. Is this even possible? Yes (given that it exists). There is no way to correctly answer this question as it really ...


0

You are right to be suspicious. I would contend that, in most situations, hypothesis tests based on the normal distribution are not appropriate. If hypothesis testing is needed, a permutation test should almost always be used. As WYSIWYG points out, there is no reason to assume a measurement is normal distributed without strong a priori knowledge. The ...


7

kmm's answer is great and complete; I just want to add some of my points on what kind of data should follow Gaussian distribution. Unless you know from observation that a process doesn't follow a Gaussian distribution (e.g., Poisson, binomial, etc.), then it probably does at least well enough for statistical purposes. I won't fault kmm for this ...


7

You raise two issues, both of which might be better suited for stats.SE, but I think the questions are suitably biological to warrant an answer here. Do most biological processes follow a Gaussian distribution? Unless you know from observation that a process doesn't follow a Gaussian distribution (e.g., Poisson, binomial, etc.), then it probably does at ...


6

Parallel DNA helix can exist and this has been observed experimentally. However these structures are stabilized by Hoogsteen type base pairing [1,2] and not the usual Watson-Crick type pairing because the parallel conformation does not allow the latter (See the figure below). This elongates the hydrogen bonds and also causes a loss of one hydrogen bond ...


-3

This is more chemistry than Biology. Both strands of DNA are 5' to 3' direction. Why so? because the direction is determined in terms of the direction in which purine or pyrimidine bases are added. The four bases that exist in DNA are Adenine, Guanine, Thymine and Cytosine. They are referenced under Purine and Pyrimidine links posted above. This molecule ...


2

From the way I have read what you have written z(1-z) translated into a sentence would be the frequency of the neutral variant (z) times the frequency of all other possible variants (1 - z) at the particular time t. Nucleotide diversity is then the average of 2 times the sum of all of the frequencies of neutral variants (z) times the the frequency of all ...


2

The term allelic class is defined in Innan and Tajima (1997) Suppose that there are two nucleotides, say A and T, in a particular site.Then, we can divideDNA sequences into two classes: one class includes sequences with A and the other includes sequences with T in this site. We call such a class an allelic class Two elements that were misleading (for ...



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