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 don't housekeeping genes have TATA Box regions in their promoter sequences?

Housekeeping genes are genes that are continuously transcribed. Like all other genes they have promoter sequences, but they don't have TATA box sequences that are used to specify from where ...
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29 views

DNA binding Domain [closed]

How to say whether a specific amino acid in a protein is binding to DNA or not from sequence alone and what are the features or characteristics to be considered?
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59 views

How do the major and minor grooves in the DNA helix arise?

I understand that they arise due to the pairing of bases of two opposite stands and are sites through which important proteins needed for replication and transcription of DNA interact. But I don't get ...
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1answer
66 views

What is positive and negative supercoiling?

Is the following correct? Positive supercoiling = the coiling of DNA helix (B-DNA) on itself during intesified coiling of the two DNA stands in right handed direction negative supercoiling = the ...
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1answer
35 views

BWA-MEM single strand or doublestrand alignment

In whole genome secondary analysis does BWA-MEM use a double stranded fasta reference or are reads aligned to only one, single stranded fasta reference?
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1answer
50 views

Does DNA polymerase I require a $3^\prime$ end?

DNA polymerase III adds nucleotides in the $5^\prime \rightarrow 3^\prime$ direction because it can only add nucleotides to the $3^\prime$ end of the previous nucleotide. This is why it requires a ...
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Hydrogen bonding and the blocking thereof in nucleic acids during nuclear processes

In transcription, RNA polymerase unwinds the DNA double helix and begins attaching RNA nucleotides to the template strand. In its wake, the DNA double helix closes back—this is only natural, seeing as ...
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0answers
20 views

From DNA to final traits of microorganisms? [closed]

From the answer of this topic, could someone indicate me a book or article about how DNA set the phenotype of microorganisms? For example, showing how DNA changes the shape of such a cell or how DNA ...
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1answer
31 views

DNA Topology. Question on twists and writhes

Hi guys there is a question which has been driving me crazy ever since I saw this video(https://youtu.be/az2c6UbEdug). At 4:50 the guy says that when a right-handed circular DNA starts forming a right ...
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25 views

Color of DNA, available absorption energy levels of DNA molecule, mutations

I have done a couple of DNA separations and observe that the clumped strands of DNA are white. Is that an artifact of the chemicals used in standard separations? Or is it indeed the case that the DNA ...
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3answers
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Is Chargaff's rule really applicable?

Chargaff's rules states that DNA from any cell of all organisms should have a 1:1 ratio (base Pair Rule) of pyrimidine and purine bases and, more specifically, that the amount of guanine is equal ...
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2answers
80 views

Getting PCR amplification at annealing higher than Tm!

I am amplifying a gene where in a gradient pcr i am getting amplification at an annealing temperature about 5 degrees (67) higher than Tm (62.5)? What is wrong here? Also, I am getting a very strong ...
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5answers
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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 ...
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23 views

Infer type of nucleic acid based on number of nucleosides

Lets say we analysed a nucleic acid and found out that it had 20% Adenosine, 25% Guanosine, 40% Thymine and 15% Cytosine. We know that A always pairs with T and G with C. So, based on these numbers, ...
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0answers
18 views

Separate replication origin and terminus vs making them one and the same

The classical picture of bacterial reproduction has a replication origin on one side of the circular chromosome and a replication termination area on the opposite end. This essentially creates two ...
4
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2answers
190 views

Is the DNA different in each type of cell? What DNA is passed to offspring?

Our body contains many different types of cells and each of those cells have their own DNA (correct me if wrong) like skin cells their own DNA that makes them skin cells instead of muscle cells. So ...
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1answer
75 views

Distinguishing Father from Brother

Given the (non-identical) DNA sequences of two men and the knowledge that the second man is either the father, brother, or son of the first man, is the DNA useful in determining which of these three ...
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0answers
21 views

Transgenic Plant-Gene source for introduction into host organism

Let's say the plant-gene itself is known, i.e. the exact neucleotide sequence is available in a gene bank (originally sequenced from a tree sample extracted RNA). Previous work has already successfuly ...
4
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1answer
127 views

Do DNA supply houses maintain a watch list for dangerous oligos (Anthrax, Smallpox, etc.)?

The recent work by DeLoache, et al. on a synthetic opiate-precursor production pathway in yeast has generated a lot of scare stories in the media about people homebrewing heroin as easily as they ...
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41 views

Was the frequency of mutations more during primitive earth due to radioactivity?

Primitive earth was more radioactive (or was it really?) according to radiometric analysis of C14 which suddenly appeared at 4250 million years in the Hadeon eon. Is it possible that ancient high ...
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1answer
47 views

What does “~mitochondrial DNA ~bp linear DNA” means?

I'm surfing NCBI website -Nucleotide- to find some examples of real DNA sequences to use in my small homework project. My question is related to the title of a DNA sequence below: Sus scrofa ...
3
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2answers
574 views

What are the major causes of mutations in DNA?

I know that point mutations can change the base sequence of a gene by altering a specific codon that codes for a particular amino acid. Are these mutations purely random events that occur when DNA is ...
5
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1answer
157 views

Is DNA replaced after organ donation?

If an organ from person A is transplanted to a new human body B, is it possible that we can detect A's DNA in B? How long until the organ's DNA is replaced by B's DNA so that we are no longer able to ...
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1answer
43 views

Why do Major and Minor grooves exist in dna strands? [closed]

I've been trying to find what causes the periodic appearance of major and minor grooves in DNA but have not yet been successful. Geometrical explanations would also be appreciated as I cannot ...
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1answer
50 views

How does the splicing enzyme recognize where to splice the introns?

When the DNA from the nucleus is transcribed to an mRNA, the mRNA is spliced by an enzyme before it goes outside through the nuclear pore. What is the name of this enzyme and how does it recognize ...
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2answers
47 views

“Prime” structure of DNA Double Helix: Confusion

In this video on DNA replication, the diagram shows the unwound DNA as still being anti-parallel, but the first diagram in this post on Biology SE shows that the individual strands are 5'____5' and ...
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1answer
89 views

The Semi-Conservative Model of DNA Replication: Question

My Campbell's Biology textbook contains the following diagram related to the semi-conservative model of DNA replication proposed by Watson and Crick. I have highlighted where my confusion arises in ...
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30 views

Is DNA transcription inactive during mitosis ie no proteins are made? How does the cell survive?

I've read that during mitosis, DNA exists as heterochromatin, a form that is unable to be accessed for transcription. Does this mean no new proteins are made during what can be 20% of a cell's life? ...
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1answer
29 views

Constant or variable number of chiasmata during recombination?

During recombination, is the number of chiasmata consistent for each gamete and are the chiasmata regions consistent within a single organism?
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1answer
804 views

How are 23 chromosomes in human sperm chosen?

I'm not biologist and I have just a basic knowledge. I've been thinking for a long time about the following question: How does the body choose which 23 chromosomes should be active in human sperm and ...
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1answer
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How old is the oldest intact DNA?

DNA fragments are known from bone fragments from the Mesozoic, but these don't count. I'm guessing the oldest DNA is recovered from permafrost, but how old exactly?
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1answer
54 views

Are nucleotides at the ends of DNA stripped on aging?

I had the following understanding (now after reading a popular science article seeming wrong understanding): DNA in (regular) cells (in human and some other organisms) are protected by telomers. ...
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0answers
11 views

Where can one find completed and processed Hi-C datasets?

I and a statistics graduate student at UCR, and I am working on Optimal Binning schemes and peak detection in Hi-C data analysis (a dataset that conveys information about proximity of a DNA strand ...
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1answer
24 views

DNA extraction for LAMP assay

I am trying to set up a LAMP assay (Loop-mediated isothermal amplification) for the detection of E.coli. I was told that EDTA can chelate the Mg in my reaction and thus prevent the assay from working ...
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1answer
105 views

why is cellulase not found in animals? [closed]

As it is really beneficial for all organisms, why are animals, especially mammals (I don't know about other vertebrates) unable to synthesize cellulase enzyme in their body? Is it linked to some DNA ...
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1answer
221 views

Why are the genomes of Humans 99.5% the same?

Human's DNA sequence is said to be roughly 99.5% equal. As far as I understand, this means that if I walked up to you and compared our DNA, the sequence of base pairs would be 99.5% the same. My ...
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0answers
20 views

Why only human have noticeable difference in face? [duplicate]

Our facial appearance is pretty much different from each other unless we are talking about twin. Credit goes to crossing over of chromosome. But why can't we distinguish between other animals of same ...
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0answers
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final control prior to transfecting an expression vector into a mammalian cell?

I have been asked a general question: Once I have cloned a full-length cDNA into an expression vector, what final important control must I do before I transfect this into an embryonic stem cell line? ...
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Which DNA fragments do not have expected sizes on this gel electrophoresis?

The problem is such: After performing a PCR, the vector carrying the PCR fragment with two restriction enzymes (Nhe1 and Asc1). The DNA samples were then separated using agrose gel electrophoresis ...
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1answer
72 views

Write the haplotypes of the family

I'm doing old exam assignments to prepare for my finals on Monday and I've stumbled on one assignment that I'm not sure how to tackle. A family with 2 children is examined for cataracts using PCR ...
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1answer
48 views

what are examples of experimental designs on exposing materal for degradation

if one wanted to compare how sources of DNA would degradate in various conditions(environmental) how would they do this in an experimental fashion but also be best comparable to real world examples of ...
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2answers
198 views

What errors can occur during DNA replication?

When there is an error in copying DNA (a mutation), what exactly goes wrong? If G goes with C and A goes with T, I don't see how that part can mess up. Is the idea that when the double helix is ...
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0answers
42 views

What are the effects of non-ultraviolet light radiation on DNA?

I am trying better understand the effects of varying the frequency of light on DNA, however, most of what comes up is "UV light" and how it is damaging to DNA (presumably by ionization). Have there ...
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Known ways to modify the genetic structure of the 13 loci used in CODIS

After reading the answer to Does our DNA change during our lives?, I was wondering if and how it would be possible to change the structure of the 13 loci that are used in the CODIS database, in such a ...
0
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1answer
38 views

Can you force human body to mass produce specific proteins? [closed]

I've had difficulty finding an answer to this question on Google. From what I've been taught, DNA is used as a "naive blueprint" to synthesize proteins. If we can manipulate DNA (Which I hear we ...
3
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1answer
125 views

In CRISPR bacteria, how does viral genomes get integrated into the spacers of CRISPR? Also, in its use, where does Cas9 cut the DNA?

I've been out of Biology for about a year polishing my programming skills. I know CRISPR/Cas9 allows targeted 'cutting' of DNA via RNA-guidance. Few questions regarding this. Regarding to its ...
3
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0answers
22 views

What are flagged primers? [closed]

I'm interested in amplifying a sequence for further use with Gibson Assembly. I want to create overhang regions in my DNA fragment so there would be complementarity to the plasmid I'm trying to insert ...
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2answers
2k views

The Uniqueness of DNA Paradox

How can everyone have unique iris and fingerprints? After a certain amount of human beings have lived on earth, wouldn't it be possible to exhaust all possible combinations? The same principle ...