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29

This entire answer will be long, so read the short part first, then read the rest if you (or anyone else) is curious. Citations are included in the long section. I can include additional citations in the short section if needed. Long Story Short You're question touches on some common misconceptions about how the evolutionary process. Organisms don't "want" ...


10

About your question This kind of very basic question has the drawback to need a very long answer. In consequence your question might get some close vote. I'll do my best to help but you might want to look at some source of information as an introduction to evolutionary biology. A book eventually or Khan academy maybe. Darwin's evolution theory The ...


7

Short answer version: It seems plausible to me that we (advanced life) could have a biological mechanism to "write" needed alterations into either our own DNA or our reproductive DNA over time, triggering the very specific evolutionary developments necessary to our survival without relying on random mutation. No, it's not. Despite what your ...


5

The phenomenon of using different codons with different probabilities is called codon usage bias. How the different codons are used is sometimes pretty different between species and requires some care. This is especially true when you want to overexpress sequences in bacteria to produce protein, which may need codon optimization to ensure an optimal codon ...


5

Any time a species has needed the development of a specific feature to survive, it has developed that feature, and that feature precisely. This statement is clearly false. The dinosaurs didn't develop what they needed, did they? It turned out that on this occasion, the mammals happened to be best adapted to the conditions at the time, just as ...


4

Here is what the data says. UK government must have had some scientific evidence when it settled on a 10 variable-length sections of genome for their database, SGM+. In one such variable sections, some people have 10 repeats of CTTT, others have 11, others have 12 etc. The largest of those fragments, at its maximum length, are about 350 base pairs. The US ...


3

The codon usage biases are species-dependant, so you may have to measure it for the genome or set of genes you are interested in. This bias is at least in some cases correlated to the genome composition in terms of A, T, G and C (see figure 3 of this paper about cyanobacteria). So in a sense, it is indeed dependent on the context if you include nucleotide ...


3

The answer provided by Mike Taylor is just perfect and complete. However, I'd like to add some thoughts of my own in a more colloquial style: Survival of the fittest is not always true. There is also "survival of the luckiest" (e.g. the fittest is showing off in the beach with the other turtles and is struck by lightning). Reproduction is not that ...


3

When designing PCR primers we typically use a minimum length of 20 bases, because the probability of a sequence of N bases appearing by random is $\frac{1}{4^N}$, and $\frac{1}{4^{20}}$ is about 9x$10^{-13}$, or about 1 in a trillion. Since the human genome is a little over 3 billion bases long, a 20 base sequence should appear only once. However, most of an ...


2

It is not unlikely that nicking is causing trouble. The question is if repeated freezing and thawing is causing the problem, there is an article which has been published in B.R.L. Focus in 1983 which disputes this effect. You can find the PDF with the article here, the article itself starts on page 10 in the PDF. On the other hand there is this paper ...


2

If your looking at transcription then your talking about RNA POLYMERASE. And there are many variants. Here's a good Nature paper that discusses temperature and RNA Pol http://www.nature.com/ncomms/journal/v1/n6/full/ncomms1076.html And another: http://www.ncbi.nlm.nih.gov/m/pubmed/12729734/ I couldn't get full access to this JBC paper but I think the ...


1

The units here are relative units of intensity. There may be about a picomole of probes on a microarray spot, but the units of intensity are not scaled to the precise concentration of DNA on the spot. There are many variables which make exact measurements of intensity difficult to translate into the number of RNA bound to a spot. The main one is ...


1

Apparently it wasn't. According to Wikipedia, A study that reported Dinosaur DNA was, mitochondrial cytochrome b sequences that had apparently been extracted from dinosaur bones dating to over 80 million years ago (reference). However, contamination was found in the reported study (reference). Don't expect too much because this is a close to ...


1

If the ladder is on an edge of the gel, it may be a process of different density as a result of how the gel cooled (or was poured too slowly). I've loaded more DNA loaded in a gel and it doesn't cause this kind of warping for me. It may be the buffer of the ladder is different from that used to make the gel. Your bands don't look particularly sharp, so I ...


1

To add to the previous answers that treat specifically of the biological Darwinism, there is also Universal Darwinism which postulates that evolution is a natural phenomenon that appears when a set of conditions and constraints are present. And indeed, it has succesfully been applied to a number of fields (see below the quote), which seems to imply that ...



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