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

learn more… | top users | synonyms

0
votes
1answer
538 views

SNP genotyping using PCR

I read this wikipedia article on SNP genotyping and wasn't able to understand this part : In examining the results, if a genomic sample is homozygous, then the PCR products that result will be ...
1
vote
2answers
1k views

Gel electrophoresis after RNAse treatment

I do not understand how to solve this question. I know that RNAse will cut smaller pieces of RNA. The answer given is A
3
votes
1answer
180 views

Real-time PCR delay in Cq due to insertion SNP in primer

I am collecting evidence, even anecdotal, how does single nucleotide deletion or insertion in primer region affect the outcome of real-time PCR. I am most interested in how much there is a delay in ...
2
votes
2answers
187 views

Stay young by reinserting own DNA from years ago?

As far as I know, the DNA sequence becomes shorter every time a cell divides. A shorter sequence results in information loss and aging characteristics. As a countermeasure, shouldn't one stay young ...
0
votes
1answer
427 views

A basic example of the interactions of 2 or more non-identical alleles leading to an advantageous outcome for an individual organism

Could someone help me out with a basic example of the interactions of 2 or more non-identical alleles leading to an advantageous outcome for an individual organism? Based on empirical research OR on a ...
4
votes
1answer
617 views

Effect of single nucleotide deletion or insertion on primer annealing

How is primer annealing, and, consequently, PCR amplification affected by single nucleotide deletion or insertion inside the primer ? Imagine a primer like this: GCGTCATAAAGGGGACGTG (primer) and ...
1
vote
0answers
62 views

DNA fingerprinting

I would like to make my own DNA fingerprint - just for fun to have my "autoportrait":). I was looking around a bit and all the commercial kits you can have are very expensive. Can you suggest me a ...
1
vote
3answers
127 views

What is the datatype of dna sample?

What is the type of data you get when analyzing dna of a person? If you want to store them in a database, what type of field you will need (text,number,hex)? And what should be it's length?
1
vote
1answer
317 views

Codon alignment via Python? [closed]

I have pairs of coding DNA sequences which I wish to perform pairwise codon alignments via Python, I have "half completed" the process. So far.. I retrive pairs of orthologous DNA sequences from ...
1
vote
0answers
225 views

Transcription takes place from the 5’ to the 3’ end of the m-RNA. Why?

Only one side of the DNA ladder is copied (the sense side). The sense side starts with a 3’ end. This means the corresponding mRNA will have to assemble starting from the 5’ end. This is my initial ...
6
votes
2answers
138 views

How much DNA of mitochondrial origin is incorporated in main cell's DNA?

And especially three points : in which chromosomes is it located (especially for the human case) ? how do we know about it ? does the proportion and composition vary a lot from one eukaryot to ...
2
votes
1answer
1k views

DNA degradation rate

Usually DNA sample manipulation is realized with an ice box at hand in order to avoid degradation, and also its storage is set at -20ºC. Nevertheless, DNA has been obtained from really ancient samples ...
4
votes
4answers
439 views

Is there a PSI-BLAST for nucleotide sequences?

I understand that one can translate a nucleotide sequence and run PSI-BLAST on the protein (proteins if you take the 6 reading frames), but I'm looking for distant homology for bacterial small RNAs ...
3
votes
1answer
271 views

What is the most genetically simple organism except viruses?

What is the most genetically simple organism (except viruses) on this planet? By simple I mean the least number of genes.
5
votes
1answer
228 views

Mitotic crossover happens in G1?

I was reading this article in wikipedia and came across this : It has been suggested that recombination takes place during G1, when the DNA is in its 2-strand phase, and replicated during DNA ...
4
votes
2answers
173 views

Is solving cancer required in order to avoid aging?

When the telomerase enzyme is not active the telomere shortens every time the cell duplicates leading to a reproductive limit (Hayflicks limit). On one hand this is a believed reason for aging. On the ...
5
votes
3answers
224 views

How easy is it to carry out de novo sequence assembly?

Today a colleague of mine asked the following question: " Assuming I need to build from 0, a chromosome of a fish, with short reads but no other reference whatsoever [de novo assembly]: ...
1
vote
1answer
69 views

Clarification of the procedures to amplify cDNA needed

The typical procedure to obtain cDNA from genomic extracted DNA is the following: RNA is extracted from desired tissue, RNA/DNA hybrid is obtained by virtue of reverse transcriptase RNA dependent DNA ...
4
votes
3answers
262 views

Why do we need deep sequencing?

Why do we need deep sequencing? Why cannot the sequencing technologies read all the nucleotides correctly at the first read? Sorry since this question is too trivial, I don't have a biological ...
1
vote
0answers
34 views

what are hyperbranched amplicons in DNA sequencing?

I am reading an article about single-cell sequencing: http://www.nature.com/nbt/journal/vaop/ncurrent/full/nbt.2720.html And came across the concept of "hyperbranched amplicons". I googled for it but ...
4
votes
4answers
335 views

Biodiversity is restricted by genome combinatorics?

Me and some friends are interested in opinions for the following: Conjecture The maximum number of species must be limited by the maximum combinatorial/permutational space that can be occupied ...
1
vote
0answers
89 views

3' or 5' DNA capping protein

Does anyone know of a protein/molecule that can be attached to one end of the DNAs temporarily ? eg. i would like to only to allow one strand of DNA be ligated to another DNA molecule to either it's ...
0
votes
1answer
3k views

What is the difference between SNP and STR?

I thought that these were just different format of the same data. But it seems there isn't a way to convert SNP (single nucleotide polymorphism) data to STR (short tandem repeat) data. Am I right? ...
1
vote
1answer
712 views

Can two denatured DNA strands reassociate?

What matter if I increase the temperature to 95°C. So double-strand DNA denatured into two ssDNA, and then I decrease the temperature to room temperature. Are they able to reassociate after ...
4
votes
1answer
503 views

How much does the Hayflick limit/telomere length vary across taxa and within humans?

Since they seem to be quite connected, I'm curious if anyone knows of research comparing the Hayflick limit (and presumably by extension telomere length) between different taxa. I've heard the ...
1
vote
1answer
154 views

Why use DNA polymerase in making cDNA?

RT is capable of synthesizing a complementary dna strand ( as in HIV life cycle.) Then why is DNA pol used when cDNA (synthesizing the second strand of it ) has to be synthesized from mRNA ( For eg.to ...
4
votes
1answer
394 views

Stability of helical strands of DNA?

The DNA molecules contain phosphate groups involved in $3'\rightarrow 5'$phosphodiester linkages. These groups, in the bonded state with deoxyribose, contain 1 negative charges ($\ce{3'-PO4^{-}-5'}$). ...
3
votes
1answer
2k views

Telomere shortening during replication

It is widely know that each cell cycle during DNA replication some fraction of the telomeres is lost, and this phenomenon is called the end replication problem. Well this is due to the fact that the ...
4
votes
2answers
9k views

Difference between CDS and cDNA

What is the difference between Coding Sequences (CDS) and cDNA? Are Coding sequences the sequences that is transcribed to mRNA and cDNA in contrast DNA obtained by reverse polymerization of matured ...
3
votes
1answer
104 views

Transposons and the net amount of DNA

The retrotransposons and certain DNA-transposons, are "jumping" sequences which may be incorporated elsewhere in the genomic DNA of an organism, through varying mechanisms. This insertion is almost ...
3
votes
3answers
233 views

How to learn molecular biology through pubmed research articles?

Instead of using a textbook, is there an alternative curriculum, that simply lists a set of pubmed research articles for each topic covered in a typical undergrad molecular biology course? I am ...
7
votes
1answer
3k views

Difference in length of Okazaki fragments

The length of Okazaki fragments in the lagging strand is about 100-200 nucleotides in eukaryotes and about 1000-2000 nucleotides in prokaryotes. What (molecular mechanism, enzyme type ) ...
2
votes
2answers
303 views

How much natural genetic variation is there between bacteria of the same species?

There are lots of questions about how and why there is genetic variation between organisms of the same species, but I haven't been able to find a numerical value for the expected amount of genetic ...
2
votes
3answers
952 views

Are all body atoms really recycled several times during a life?

I heard a point, that all (human) body atoms are recycled withing short period like few years. Recycled means "old" atoms are replaced by "new" ones during metabolism, leaving only structure ...
2
votes
1answer
212 views

Should the length of the electrodes in the electrophoresis chamber be proportional to chamber's size?

I am trying to build a small horizontal electrophoresis chamber from scratch. I want to use it for comet assay and I will be using only 1 slide, so it's going to be about 3cm wide, 10cm long and 4cm ...
2
votes
1answer
882 views

What is Luc Montagnier's research on electromagnetic signals from DNA about?

After reading a Youtube comment, I started reading on Luc Montagnier's research on electromagnetic signals from DNA. I haven't been able to find a source that would clearly explain what it's about. I ...
4
votes
1answer
236 views

Microarray data and analysis tools

Microarray has various uses, and to analyse the data a main function classification is used. There are many methods used to classify the data but what are the best and most frequently used methods? ...
1
vote
1answer
53 views

Reassociation of DNA

What is the order in which this DNA samples would would reassociate ? e.coli DNA plasmid DNA viral DNA satellite DNA DNA-RNA hybrid This is a homework question and I have not been given any ...
2
votes
0answers
112 views

What to do with a DNA sequencer? [closed]

My school is very fortunate to have a DNA sequencer, and I want to find an opportunity to learn how to use it. I'm currently taking AP Biology this year, and I hope to do an independent study in ...
1
vote
2answers
134 views

Would it be correct to state that any biological difference between the sexes has to be found in the Y chromosome?

If the reason Why Men Don't Listen and Women Can't Read Maps is genetic, then one of the genes in the Y chromosome is to blame and in theory could be identified. Correct or incorrect?
1
vote
1answer
46 views

Genotoxic agent and their metabolic pathway

What are the mechanics (set of biochemical reactions) allowing a given genotoxic agent to modify the mutation rate at a given spot? to induce only a given type of mutation (from Gs to Cs for ...
6
votes
1answer
73 views

Is telomere shortening consistant over consecutive cell divisions from zygote to a differentiated cell?

Considering the complexity of embryogenesis, a temporal referance would be helpful to coordinate the developmental sequences during embryogenesis and fetal development which is to be completed within ...
8
votes
3answers
13k views

Does our DNA change during our lives?

As far as I know, DNA is the construction protocol of all organisms on Earth. Does it change when influenced by time and environment (physical laws)? As parents with schizophrenia are more likely to ...
2
votes
2answers
292 views

Basic text/notes on DNA structure (for non-biologists)

I am a mathematics grad student researching knot theory, and I've recently discovered that there is a connection between knot theory and DNA structure (if I understand correctly, when DNA strands ...
4
votes
1answer
957 views

Which organisms have introns?

From Wikipedia: For example, introns are extremely common within the nuclear genome of higher vertebrates (e.g. humans and mice), where protein-coding genes almost always contain multiple introns, ...
3
votes
1answer
1k views

Why are urban birds still scared of humans?

I understand that animals are naturally scared of humans because we basically slaughtered every living thing we found in our way for millennia. How long does it take for them to genetically 'forget' ...
1
vote
1answer
211 views

Do spouses begin to share genes over time?

I apologize if this hypothesis sounds strange by I was wondering if any research had been done on a phenomenon which I've seen and have corroborated with many other - the idea that over time spouses ...
5
votes
2answers
149 views

There are linear and rotary molecular motors in the cells. Do any of them have a fixed or stable frequency or speed?

Are there any linear, rotary or oscillatory molecular motors in the cells which can have fixed frequeny and which can be used as a reference for elapsed time timer? This question is with relevence to ...
2
votes
1answer
103 views

How correlated are proximally related CpG sites in human DNA?

Cytosine residues in DNA that can be methylated (i.e. CpG sites) are likely to be in the same methylation state if they are geographically (proximally) close together. I can only find one paper that ...
1
vote
1answer
199 views

Complementarity of cDNA

Strictly speaking, what is the definition of cDNA? This confuses me, since usually it is said to refer to DNA that is complementary to mRNA. Is this correct? Is it restricted to mature mRNA? I ...