Deoxyribonucleic acid (DNA) is the carrier of genetic information, including for all known living organisms. The only known exceptions are RNA viruses.

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Why is uracil used in RNA rather than thymine?

What is the advantage gained by the substitution of thymine with uracil? I have read previously that it is due to thymine being "better protected" and therefore more suited to the storage role of ...
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4answers
2k views

Life without DNA?

I'm by no means an expert in the field, merely a curious visitor, but I've been thinking about this and Google isn't of much help. Do we know of any lifeforms that don't have the conventional ...
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How do cockroaches resist the effects of ionizing radiation?

Cockroaches are very hardy insects. It is known that, among other things, they are able to withstand bursts of ionizing radiation that would kill a human being. The explanations of this observed ...
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What exactly are computers used for in DNA sequencing?

I've thoroughly read the Wikipedia article on DNA sequencing and can't get one thing. There's some hardcore chemistry involved in the process that somehow splits the DNA and then isolates its parts. ...
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4k views

What is the advantage of circular DNA in bacteria?

From what I understand, bacteria have circular DNA. What advantages does it have over linear strands like for eukaryotes? Do there exist bacteria with more than one ring of DNA?
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381 views

Is telomere length a reliable measure of health/lifespan?

Several companies are commercializing tests for telomere length such as this one here. I understand the basic mechanism for why telomeres shorten during DNA replication, but how good is the evidence ...
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Why do eukaryotic organisms have introns in their DNA?

We touched on introns and exons in my bio class, but unfortunately we didn't really talk about why Eukaryotes have introns. It would seem they would have to have some purpose since prokaryotes do not ...
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1k views

Which organism has the smallest genome length?

Which animal/plant/anything has smallest length genome?
17
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2k views

Why are there exactly four nucleobases in DNA?

Does someone know why DNA is composed of four nucleobases? In particular, is there an explanation for the number? Why four and not two, or eight?
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851 views

Could Junk DNA be used as a Turing Machine by nature?

In what ways has DNA been studied to see if there a "programmable" aspect to it? Has nature produced anything resembling a Turing machine within the cell, perhaps using the "junk DNA" as its code? I ...
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223 views

Can methylation from DNA get copied to RNA during transcription?

Methylation on gene-body and 3'UTRs if copied to mRNA can potentially regulate post-transcription modifications or expression regulation. But I'm not sure if they are maintained after transcription or ...
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Is there an advantage to linear chromosomes?

The DNA copying enzymes have a hard time working to the end of a chromosome. For circular chromosomes this is not a problem, since there is not a sharp 'end'. However, for a linear chromosome, without ...
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Why is DNA replication performed in the 5' to 3' direction?

DNA replication goes in the 5' to 3' direction because DNA polymerase acts on the 3'-OH of the existing strand for adding free nucleotides. Is there any biochemical reason why all organisms evolved to ...
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981 views

What implications has the missing 2'-OH on the capability of DNA to form 3D structures?

The chemical difference between RNA and DNA is the missing 2'-hydroxyl group in the nucleotides that build DNA. The major effect of that change that I know of is the higher stability of DNA compared ...
13
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2answers
202 views

What is the contribution of viruses to the evolution of mankind?

I'm interested in horizontal gene transfer in bacteria, viruses, and organisms such as Bdelloid Rotifers. I've just read in Carl Zimmer's 'A Planet of Viruses' the following passage: As a host ...
13
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1answer
189 views

What is the prehistory of amino acids in cells?

As a followup to Why 20 amino acids instead of 64? and What is the smallest number of amino acids required for life?, I am trying to understand the prehistory of amino acids in cells. All living ...
12
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405 views

Why did high A+T content create problems for the Plasmodium falciparum genome project?

The main paper for the Plasmodium palciparum genome project (Gardner et al., 2002) repeatedly mentioned that the unusually high A+T content (~80%) of the genome caused problems. For example they imply ...
12
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1answer
202 views

Abiogenesis: Beyond the research journals as a lead in to discussions on evolution

I just came across this abstract: Aminoacyl-tRNA synthetases (aaRSs) are responsible for creating the pool of correctly charged aminoacyl-tRNAs that are necessary for the translation of genetic ...
12
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8k views

How many agarose gel bands are typical for circularised DNA

I am aware that circular DNA can be both relaxed and super coiled. However when running an agarose gel of the circular plasmid along with singly digested plasmid with BamHI and HindIII, I see 1 band ...
12
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301 views

What is Curved DNA?

CbpA is DNA binding protein found in E. coli and binds non-specifically to curved DNA (Cosgriff et al., 2010), when the bacterium is in a static phase of growth. The use of "curved DNA" confuses me. ...
12
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1answer
236 views

Can DNA act as a translation substrate?

I get conflicting answers. One would think if it was true, it would be rather seminal and widely known. There are papers from Khorana[1], Holland[2], and Bretscher[3] (late 60s) that suggest that it ...
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250 views

What can you tell about a person, having only their whole genome as information?

Well, the question is in the title, no explanation need.
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145 views

Is there any other function of DNA?

We all know that DNA acts as a genetic molecule. Does DNA have any other function in the cell other than being a genetic material and carrier of information?
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5k views

Does an annealing temp higher than primer's Tm contribute to primer dimer?

I am attempting to reproduce results from a number of journal articles all referring to the same SNP. In doing this I'm using the same primer set outlined in the articles. When I attempted a run the ...
11
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1answer
425 views

How do CpG islands remain unmethylated?

In most of the genome CpG sites are pretty much always methylated, but CpG islands are instead often unmethylated. This has been linked to the fact that they often are associated to transcripted ...
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299 views

What are the limitations to current nucleotide sequencing technologies?

Using the Illumina platform, it is cheap and (relatively) easy to sequence huge amounts of DNA or RNA. There are various other platforms out there (Roche/454, SOLiD, PacBio, Ion Torrent) each with ...
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171 views

Can DNA produce ribozyme-like structures?

RNA is known to act as an enzyme via its ability to fold itself in specific ways. Is DNA capable of such structures? Or is it some biochemical reason stopping the folding? Have they been observed in ...
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1answer
163 views

How can you identify if a person is homozygous for a certain allele?

I've been thinking about starting a small private research project. In this project I need to find out whether a person is homozygous for a certain allele. The reason for this is that I'm really ...
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1answer
2k views

How to DIY preserve pet DNA today so that it can be used in 20 years

I know that there are companies that offer a kit+storage of your pet DNA for around $2k. My question is if there is any other option for doing this yourself with a thought in mind that in 20+ years ...
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1answer
533 views

Why is the 3'UTR region highly methylated in most of the human genes?

Most of the human genes are found to be highly methylated in their 3'UTR region (0.8-0.9%). I was wondering if there is any specific reason for this?
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183 views

Does GFAJ-1 use Adenosine triarsenate as its energy currency?

Regarding the bacteria found in Mono Lake, CA that scientists believe uses or can use arsenic in its DNA backbone where life as we know it uses phosphorus (according to their experiments depriving the ...
9
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378 views

Source of DNA sequences

I'm working on a project where I am taking DNA sequences and translating the codons into musical notes. I have some good ideas of how to do this, I'm just not sure what sequences to work with. My case ...
9
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1answer
15k views

Why do we add salt when precipitating DNA?

All the DNA extraction protocols I have seen involve adding salts to the extraction buffer. What is the purpose of the salts? What happens if they aren't included?
9
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393 views

Do mitochondria simply automatically convert glucose to ATP?

I wonder whether there is any intelligent decision-making in mitochondria in the timing of their operation. Do they simply begin ATP production as soon as the correct reactants are present? Or, ...
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158 views

Are there viruses that affect many kinds of cells across species?

I'm not a professional in biology nor a student, but I'm curious about this. To be more specific: why doesn't a plant virus affect animal cells? I suspect that different kinds of cells have different ...
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200 views

How can I avoid digesting protein-bound DNA?

I'm interested in sequencing and analyzing the bound DNA, and minimizing the amount of unbound DNA that gets sequenced through digestion. When digesting protein-bound DNA, is all of the unbound DNA ...
9
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1answer
262 views

Does DNA react in all of the ways most other acids do?

As I understand it from my basic chemistry, there are some fundamental reactions that exist between any acid and other substances for example acid-base reactions that form a salt, and the existence of ...
9
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1answer
1k views

Are human chromosomes connected or separate molecules?

Do the 46 human chromosomes form a single unbroken DNA helix? Or is it rather that a human's genome consists of 46 disconnected helices? If it is the former, does the common numbering scheme for ...
8
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1answer
396 views

How many gigabytes of DNA are there on earth?

The human genome is about 770 MB, the C. elegans genome is about 100 MB, the yeast S. cerevisiae is about 12 MB. Different other genomes have been sequenced: how many GB of genomic DNA we have now? ...
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197 views

What would need to be discovered to prove there is extraterrestrial life?

Curiosity is on the Martian surface and is equipped with a slew of laboratory equipment. What would Curiosity need to discover to prove there is or has been life on Mars? Would it have to find DNA (or ...
8
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2answers
125 views

What is the effective relatedness of inbreeding?

If a human inbreeds with a relative, how distant does the relative have to be before the homozygosity in the child is no higher than if the mate were randomly chosen from the global population?
8
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466 views

BLAST DNA Sequences Reversed

I have been trying to learn some basic DNA sequencing techniques and have been using BLAST as a reference. I thought that I was starting to get it, but then I cam across this: It looks like it's ...
8
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1answer
197 views

Finding DNA from Amino Acid sequence problem

My attempt: First I took the single letter AA codes and made them amino acids. So, the first one is Trp which is 5'-UGG-3'. From this I got the DNA sequence 3'-CCA-5'. However, the correct ...
8
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1answer
642 views

How is instinctual information encoded?

If instincts are passed on through genetics, how is that information encoded in DNA? For example, spiders instinctively know how to spin webs. Does that imply that the algorithm for web spinning is ...
8
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249 views

What kind of event would cause the current Mitochondrial Eve to be replaced by a new one?

Apparently all living humans are matrilineal descendants of a single woman who lived 200.000 years ago. She is called Mitochondrial Eve. But at the time she lived there was a different matrilineal ...
8
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1answer
596 views

Does every mitochondrion in a cell contain the same DNA?

I know that mitochondria of eukaryotes have their own DNA, more similar to that of bacteria than to the rest of the cell's DNA. I also know that a cell can have plenty of mitochondria, and I ...
8
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1answer
124 views

How realistic is to use DNA for long term storage?

This is mainly a followup question to the recent paper Next-Generation Digital Information Storage in DNA. Personally, while I agree about the data density of the format, I can't help point out the ...
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2answers
1k views

Altering the human genome

I recently had a conversation with a rather unusual gentleman who was, let's say, more than a little partial to conspiracy theories. He has this idea that governments are lowering "nanowires" from ...
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117 views

Free Radicals for aging

From my understanding free radicals play a slight role in ageing. In what ways are they so damaging, and can a restricted diet reduce production of free radicals?
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What distinguishes “coding” and “noncoding” DNA from each other?

I've been reading a bit about "junk DNA" and how much of our genome consists of this "non coding DNA" in comparison to "coding DNA". I'm just an interested layperson but I thought all combinations of ...