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7

(For the direct answer to your question skip to the end!) Genetic linkage can affect the spread of other genes. The degree of linkage, affected by the rate of recombination between the point (nucleotide, gene etc.) directly under selection and the other point. If the rate of recombination between to given points is low then linkage between them is high and ...


6

DNA is not made of these blocks only. But the genetic information is conveyed through the series of these four block. All animals, all plants, all fungi, all other eukaryotes, all bacteria, all archea and plenty of viruses use these four blocks. Some viruses use RNA instead of DNA, in which case the T is replaced by a U (Uracile). You will find more ...


5

Genetic hitchhiking / genetic draft From wikipedia Genetic hitchhiking, also called genetic draft or the hitchhiking effect, is when an allele changes frequency not because it itself is under natural selection, but because it is near another gene on the same chromosome that is undergoing a selective sweep. The term "selective sweep" is used improperly ...


4

The fact that there is no inter-strand cross-linking between different double strands might be just because the cross-linker cannot bridge the distance between amines of different bases on different double strands. The formaldehyde based linking of nucleobases has been described by Chaw et al. (1980) where formaldehyde bridged a gap of app. 3 angstroms (2x ...


3

Mutations are not performed targeting a specific new phenotype. There is no way an organism can "know" the impact of a specific future mutation anyway. A mutation is just a mistake in the replication process. As a consequence the majority of mutations are deleterious and only a handful of mutations are beneficial. It is true though that the mutation rate ...


2

"Reverse translation" Translation is the process by which an mRNA is "translated" into a protein. It is impossible to get the exact DNA sequence from the protein sequence because a large number different DNA strands could code for the exact same proteins. In other words, there is a loss of information in the translation process. See codon redundancy and I ...


2

Why DNA for the genetic material? I think the correct and sufficient answer to this is the one so frequently repeated that it is difficult to find the original source. For example, G.F.Joyce wrote in a 2002 Nature review article: The primary advantage of DNA over RNA as a genetic material is the greater chemical stability of DNA, allowing much larger ...


1

One option is to use SPRI beads, like those sold by Ampure (Ampure XP beads) to separate DNA fragments by size. By adjusting the ratio of beads to sample, you can selectively bind fragments of certain lengths by excluding those of other lengths, as seen in the following image: From this image, you might try using a beads-to-sample ratio of 0.7 to exclude ...


1

In my mind, gel separation (using a fairly high percentage gel to separate the bands as much as possible) and manual excision is by far the best option. The problem with molecular weight cutoff filters is that the value they give (5000 Da, for example) is an average pore size, it is not exact. Therefore, any attempt to separate 270 bp from 170 bp oligos will ...


1

This isn't a question with a really well accepted answer yet, and comes up quite a lot in e.g. studies of population variation in transcription factor motifs. Usually, we approximate the sequence preferences of a DNA-binding protein with a position weight matrix. A weight matrix will given you a score for two sequences, so the simplest means of quantifying ...



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