The scientific study of the structure and function of genes at the molecular level, particularly chromosomes and DNA.

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Cloning a gene of an organism with an nonsequenced genome

What would be the best protocol to clone a gene about 5kb in size? The genome is not sequenced, but the gene itself very similar to orthologous genes of organisms with known sequences.
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Understanding DNA supercoiling

While trying to understand DNA supercoiling, I came across these lines in the book Genetics by Ursula Goodenough : All natural DNA is superhelical. The axis of the duplex itself follows a ...
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33 views

Transport of mammalian insulin in vivo

What is the mechanism for transport of insulin in mammalian cells?
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Paracentric Inversion and Mutations Question Help Needed

Would someone please be able to help with questons 3 or 4. (one of the at least please) please don't report his as off-topic. first, this is NOT a homeowork question. It's a practice question I am ...
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125 views

Sexual Differentiation in Monoecious plants with unisexual flowers

In monoecious plants having unisexual flowers (eg Zea Mays, Ricinus Communis etc), there must be some mechanism as to produce two sexually distinct flowers from the same genotype. Since both the type ...
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Southern/Western blot analysis and pedigree diagram? Help needed. [duplicate]

Hello everyone. I urgently need help with this question please. I have filled in the blanks using the results in the figure provided in the sheet. However, for number (b) is a little hard to ...
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39 views

Gene Complementation Question

Hi everyone! Here is a diagram of a genetics complementation problem. My main concern is regarding number 3d. I'm assuming that in this case, it would be complementary interaction and thus ...
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143 views

What are some examples of genes that code for multiple proteins?

The title pretty much says it all. It is widely taught that a gene in a eukaryotic system could produce more than one protein due to post-transcriptional modification, but I do not believe I have come ...
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497 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 ...
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85 views

Pedigree Diagram help

I am asked to fill the genotypes in the spaces provided but looks like I am aving a little bit of trouble. can anyone help? thanks in advance!
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PedigreeAnalysis Genetics [duplicate]

Hello! I need help with this exercise question. I am not really sure which pedigree diagram is autosomal and which is not. But, is question b 1/2. Can someone give an explanation? Thanks very much ...
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48 views

What is “transcribed strand”

This is an excerpt from a paper: T>C mutations at NpTpN trinucleotides, also found in hepatocellular carcinomas, shows strong transcriptional strand bias with more T>C mutations on the transcribed ...
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45 views

Process of Transcription

During the process of Conversion to Ribonucleoside Monophosphates the various ribonucleoside triphosphates break off their high energy bonds after linkage to the DNA.But the first ribonucleotide ...
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399 views

Regulation of chromatin structure

Recently, I reviewed the different levels of chromatin structure. The primary level is nucleosomes, where DNA is bound to histones, and has structural similarity to "beads on a string." The secondary ...
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What is the functional and structural distinction between core (H2A, H2B, H3,H4) and linker(H1/H5) histones?

Many explanations of histone biochemistry isn't quite elucidating for the undergraduate student. How does histone structure (dimers, octomers) relate to their specific functions as core or linker ...
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126 views

Histone marks mechanism

I am slightly confused about the mechanisms that makes histone modifications associate with gene expression. That is, H3K36me3 is believed to be present in actively transcribed genes, H3K27me3 in ...
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Embryo activity during seed dormancy?

What metabolic processes does a dormant embryo in a seed carry out? The newly produced seed will not germinate, either because of a lack of favourable conditions, seed hibernation, or because of a ...
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76 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 ...
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36 views

Regulation of the replication of mtDNA at embryonic level

While reading an article on mitochondrial inheritance I came across this link. The results state that mitochondrial DNA replication is regulated in different cells of an embryo at different levels. ...
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93 views

Ethidium bromide and mutagenesis on cloning

When performing a DNA cloning, sometimes PCR amplicon is run in agarose and it is detected by ethidium bromide marking under UV light. After that, gel is sliced, DNA extracted from gel....... until ...
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93 views

Which restriction enzyme would i use?

Plasmid pBr322 includes two genes that confer antibiotic resistance: a gene for ampicillin and a gene for tetracycline. The cutting site for the restriction enzyme BamH1 is in the middle pf the ...
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What is the reason behind choosing the reporter gene when experimenting on your gene of interest?

I noticed within example experiments in class that different reporter genes are chosen to be inserted near your gene of interest to prove whether or not the gene is being expressed. For example, you ...
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How does promoter sequence affect initiation?

I don't know if this might have been highlighted in recent research, but a textbook I have states that "the exact way in which promoter sequence affects [transcription] initiation is unclear" I'm ...
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170 views

paralogue genes in genome-wide association studies?

Has anybody tested if paralogous genes are over-represented among the genes identified by genome-wide association studies (GWAS)? For example, if a GWAS study finds 200 genes associated to the ...
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102 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 ...
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DNA and gene activation

As far as the genetic content of each cell is concerned I have read to my satisfaction that all cells of a person's body except the red blood cells (with no nucleus and so no genetic message) and the ...
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Transduction with P1 lysate prepared from strain that is proC::Tn10

If I do a transduction with a P1 lysate prepared from a strain that is pro*C*::Tn10 and the recipient is wild type, will all my recombinants be ProC- and Tet resistant since the Tn10 is in the proC ...
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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 ...
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Difference between mutation and DNA damage

What is the strict difference between mutation and DNA damage? As far as I understand it, a mutation is an alteration in the genetic sequence, having "tricked" the repairing machinery and thus ...
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Criteria for the numbering of human chromosomes

What were the criteria devised for the numbering convention employed in human chromosomes? When was it fixed? Correct me if I am wrong; it appears that chromosome pairs 1 to 22 were originally ...
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128 views

Can you detect if a mutation is spontaneous or induced?

Is it possible to determine if a certain specific mutation had a spontaneous origin (for example from a mistake of the DNA polymerase) as opposed to an induced origin (for example, from some genotoxic ...
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550 views

Methods of nuclear transfection - nuclear transport

I am reading through the ENCODE papers, which is taking me well out of my comfort zone in terms of modern laboratory techniques. At the risk of asking a question which may well be thoroughly answered ...
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what is knob heterochromatin?

I am reading a paper which discusses Maize Genome Structure. Descriptions of the structure is given in the papers introduction. I know about heterochromatin "heterochromatin stains intensely, ...
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391 views

What exactly happens if during translation, an amino acid is not present?

Lets say that the cell wants to make a particular protein. Transcription of the appropriate gene is done and the mRNA is made. mRNA attaches to the ribosome and the translation is initiated in a ...
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42 views

Is there are practical lower limit to gene length in E. coli?

Question is rather self-explanatory. Putting aside other post-transcriptional factors like rate of degradation of transcript, what is the smallest gene ever reported to have successfully been ...
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Which part of the genome are the developmental sequences of embryogenesis located?

Which part or parts of the the genome are the sequences located. Are they spread across the chromosomes? If so how are they accessed sequentially with precision during embrygenesis?
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What tests can be performed to test the purity and quality of the raw peptide HCG (Human Chorionic Gonadotropin)

What tests could be run to test the purity and type of HCG? We are looking to purchase HCG from China but the purity and quality varies between labs, we are able to receive samples of the raw peptide ...
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When DNA is at its uncondensed form, what can it do?

I think it can do two things: The cell may be duplicating the genome during S phase. The cell may be transcribing the DNA into mRNA. Question: Can the two activities occur at the same time or one ...
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503 views

Smallest unit on which selection can act

Traditionally, the individual was considered to be the smallest unit on which Natural Selection (NS) acts. Today, we usually consider the gene as being the unit of NS. Of course, we should also ...
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Is there variation of AT/CG ratio along species?

Chargaff's rules say that the number of Adenine of the number of Thymine in a genome are equal (nA=nT) and similarly nC=nG. This makes obvious sense knowing that C binds to G and A to T. But what ...
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Collective term for both exons and introns

Is there a term I can use to refer collectively to both exons and introns? By collectively, I don't mean ligated as with an unprocessed transcription product. I'm just writing about exons and introns ...
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Prenatal Marketing

This is for a short story idea. Is it possible to modify the DNA of a child to make their metabolism more susceptible (physical response, addiction, etc) to a certain type of chemical i.e. a chemical ...
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Can Pfx polymerase add only one 3' A overhang?

I am trying to clone a PCR product that was amplified using Pfx polymerase into pGemT vector. I had to A-tail the PCR product using Taq polymerase since Pfx only generates blunt end products. My ...
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How does the DNA know which chain has error in repairing?

As we know, the DNA has more stability than RNA, if one chain has broken or accidentally distorted, it can be repaired by the other one. Suppose there is a segment AGTC, its peer is GACT. Now its ...
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372 views

How is the exogenous DNA protected from degradation during bacterial transformation?

During transformation, a bacterium can take up DNA from its environment. A small fraction of bacterial species are known to be naturally competent, meaning that they can engage in this sort of ...
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163 views

Is there a practical upper limit to amount of nucleotides or genes in a transformed plasmid?

I'm currently working on a synthetic biology project which involves working with lots of different parts. I would ultimately like to integrate these genes by transforming a single plasmid. I've heard ...
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928 views

Knockdown of long noncoding RNA (lncRNA) - how is it done?

I don't work at the wet lab and don't know all the details about the knockdown techniques. My question is: How lncRNA knockdown is done? For example - you have lncRNA that is functional in the ...
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9k views

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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353 views

What is solid-phase bridge amplification?

During Illumina sequencing there is a step called bridge amplification by which DNA is amplified by isothermal enzymes. What is this stage, and how does it work?
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How do amino acids become attached to tRNA?

Is there a protein that catalyzes this or does it happen spontaneously? In which part of the cell does this happen?