Tagged Questions

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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2answers
107 views

DNA sequence from the middle of a gene

Someone gives you a short DNA sequence that comes from the middle of a gene. 5'- TCTAACTGATTAGC -3' 3'- AGATTGACTAATCG -5' From this sequence, determine the ...
3
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2answers
12k views

What does 5' and 3' mean in DNA and RNA strands?

What are 5' and 3' in DNA and RNA strands? Please clarify with some images and please use simple English.
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1answer
71 views

Do “transcription factor binding site” and “operator” mean the same thing?

Can the terms "transcription factor binding site" and "operator" be used interchangeably in all contexts when referring to a DNA sequence, e.g. regardless of a cell type, whether or not the binding ...
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1answer
56 views

The contribution of stem cells to life extension technology [closed]

What do you think is the most powerful method to extend human lifespan? I want to extend human life span significantly (hopefully extra 50 years or more), so I was expecting that stem cell technology ...
2
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2answers
61 views

Maintaining purebred pedigrees and how to lessen chance of getting disease?

Many breeds of dogs are known for a high incidence of genetic disorders. German shepherd and Saint Bernard dogs are predisposed to developing a crippling condition called hip dysplasia. Q: What ...
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1answer
86 views

is it possible to completely reconstruct a family tree by DNA comparison alone?

Having DNA samples of all or almost all members of a population of, say, a few hundred or thousand individuals, is it possible to draw the entire family tree of those individuals? (Let's not assume ...
3
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0answers
51 views

Is a single x-ray photon capable of doing enough damage to the dna of a cell to kill that cell?

Ionizing radiation is damaging to DNA, but is there such a thing as a safe dose below which no DNA damage could occur? I'm not asking about a minimum safe dose overall, just whether or not there's an ...
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1answer
57 views

In vitro transcription, contamination problem

I am using a RNA which is in vitro transcripted before I started my project. It turned out it is not prepared properly and has DNA contamination. Instead of perform the in vitro transcription again, ...
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1answer
57 views

Can a certain part of human dna can be replaced with other animals dna?

Human DNA consists of adenine, thymine, guanine and cytosine. Can thymine of other animal can be placed with humans thymine?
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1answer
627 views
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2answers
66 views

Detecting cancer or a genetic predisposition based on DNA sequencing

I am not by any means a biologist - so go easy. What would be a method for determining whether or not a patient has cancer based only on a genomic sequence? Update Thanks for the help in revising ...
3
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2answers
122 views

Question about Autosomal Recessive Alleles

I had a homework question that I could not figure out. It states: A woman has cystic fibrosis in her family and did not want to have a child that suffered from the disease. She and her spouse ...
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2answers
55 views

Removing a restriction site and introducing other at its place

What would you do if you want to remove an EcoRI restriction site and introduce BamHI restriction site at apprx. the same location ? One of the answers in my textbook was : To construct a DNA ...
1
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0answers
62 views

DNA content in seeds vs. fruit flesh

Is there a publication comparing DNA yield and / or PCR-amplifiability after extraction from fruit flesh (like apples, oranges, cherries etc) in comparison to seeds of the same fruits ? I would prefer ...
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0answers
14 views

Phylogentic Footprinting Project

I'm working on performing phylogentic footprinting to figure out how many TRE sequences there are in the TWIST1 gene. (Sequence motifs). I'm trying to use ENSEMBL to gather orthologues of species in ...
2
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1answer
42 views

Need help distinguishing between a primary and secondary source

I am trying to figure out if the following article is a primary or secondary source. I'm leaning towards secondary but here are my cases for both. Primary: Published in a peer-reviewed ...
2
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1answer
70 views

What is this image?

What I understand is- I think this is picture of DNA. But why is it in this conformation ? What types of cells have this type of DNA ?
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2answers
81 views

Reference sequence for defining single nucleotide polymorphisms

Single nucleotide polymorphism (SNP) or genetic variation in general, by definition are relative to a reference sequence. When we talk about databases of SNP as in ("dbSNP—Database for Single ...
2
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1answer
77 views

DNA ligase mechanism

I am unable to understand what happens to the phosphates from ATP. What are they used for ?Charging 3' end or 5'end ?
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1answer
83 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 ...
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2answers
406 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
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1answer
102 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
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2answers
92 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
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1answer
133 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 ...
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0answers
40 views

How is the number of histones being related to the number of chromosomes [closed]

Please name me at least one reason. I am referring to rats and to humans, as well.
4
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1answer
312 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 ...
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0answers
45 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 ...
0
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3answers
66 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?
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1answer
151 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 ...
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0answers
89 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 ...
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2answers
97 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
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1answer
247 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 ...
3
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3answers
190 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
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1answer
123 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.
2
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0answers
33 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
131 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 ...
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3answers
176 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]: ...
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1answer
49 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
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3answers
152 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
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0answers
17 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
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4answers
256 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 ...
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0answers
38 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
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1answer
518 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
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1answer
185 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
221 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
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1answer
64 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
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1answer
110 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 ($\ce{3'-PO4^{-}-5'}$). ...
2
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1answer
512 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 ...
2
votes
2answers
2k 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
77 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 ...