Hot answers tagged

13

So earth is estimated to be around 4.5 billion years old, and life has existed for about 3.4-3.9 billion years of that, around >75% the time. For a little perspective, Homo sapiens have been around for up to ~250,000 years, just 0.00005% of the time earth has existed. In that time the earth has changed massively, early earth was pretty hostile, but that ...


8

Short answer Before the RNA world, mineral surfaces may have facilitated the prebiotic containment and organization of biomolecules. Minerals are believed to have promoted the transition from a dilute chaotic prebiotic “soup” to highly ordered local domains rich in key biomolecules. Background As pointed out by others, the transition from a hereditary DNA ...


5

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 ...


3

You can do without DNA, you need RNA to make proteins. Living organisms create and maintain a bubble that is very far removed from thermal equilibrium. So, you can speculate that at the origin of life, conditions existed where processes that are far from thermal equilibrium could still occur naturally without the support structures one finds inside living ...


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 ...


2

Here is the results summary of the study that describes the discovery of DNA:RNA hybrid virus: Results Bioinformatic analysis of viral metagenomic sequences derived from a hot, acidic lake revealed a circular, putatively single-stranded DNA virus encoding a major capsid protein similar to those found only in single-stranded RNA viruses. The presence ...


2

Short Answer- No, chances are negligible. Long Answer- Digestion is a chemical process which is mediated by enzymes. Enzymes are highly choosy molecules so that they only perform the work they're made for. In digestion, enzymes like proteases (for breaking down proteins), lipases (for breaking down lipids), amylases (for breaking down starch), DNAses (for ...


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 ...


1

You do need two pairs of primers one unique to each species as you need a positive result to be confident that the thing you are looking for (cow or horse) is there. There is no limitation on them being in the same place (with a different last base). Usually this would be analyised by gel-electrophoresis and not by sequencing so you don't have to worry ...


1

No specific length for centromeres. Actually in a real chromosome in a cell, centromeres are usually very condensed sequences of DNA, they are winded and folded (if you know about the DNA structure). Thus you cannot measure the length of the centromere unless you decondense the chromosome first.



Only top voted, non community-wiki answers of a minimum length are eligible