Stack Exchange Network

Stack Exchange network consists of 174 Q&A communities including Stack Overflow, the largest, most trusted online community for developers to learn, share their knowledge, and build their careers.

Visit Stack Exchange

Questions tagged [molecular-genetics]

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

0
votes
1answer
51 views

DNA base pair heading

Does it make ANY difference to which strand of DNA double helix base pair heads? I mean, could base pair AT and base pair TA makes any difference when interpreted by biochemical mechanisms which use ...
2
votes
1answer
1k views

How does aminoacyl-tRNA synthetase recognize different tRNAs?

There are about 20 aminoacyl-tRNA synthetases, one for each amino acid. Each aminoacyl-tRNA synthetase has a binding site that recognizes a specific amino acid, and other binding areas that recognize ...
1
vote
0answers
47 views

Why our arms stop growing if mitosis never stops? [closed]

I wonder if there's a balance between cell death a new mitosis .
0
votes
1answer
222 views

Function and Characterization of poly(T) and (AT)

I came across three terms; "poly(T)45", "poly(A)45" and "(AT)15". Can anyone explain what they are? I know the number refers to strand length, possibly poly-T is a strand of thymine monomers and that ...
0
votes
1answer
40 views

What is allele-specific gene expression?

I read somewhere that the two different alleles which we (and other species) inherit from our parents are not expressed equally in our cells. Which genes show allele-specific expression? How and why?
2
votes
2answers
205 views

Is it possible to obtain single strands of DNA in solution? [closed]

Being that it is relatively simple to extract DNA from a variety of sources, what further technique can be used to separate the two complementary strands in solution?
1
vote
0answers
31 views

Is human genome editing more complicated than mice genome editing?

A lot of genome editing trials are being done on mice and rats, but I often read that the step from mice- to human genome editing is complicated. What are precisely? I guess it has something to do ...
1
vote
1answer
246 views

What's the difference between Phage DNA and Recombinant DNA

Genetic engineering: In my textbook the following sentences describe the two, but to me they seem the same: The new combination of bases in the DNA (vector DNA + DNA fragment) is called recombinant ...
5
votes
1answer
470 views

what is the meaning of VIP-cre::LSL-TOM::SOMGFP(GIN) mice?

I am reading the following paper and the researchers use "VIP-cre::LSL-TOM::SOM-GFP(GIN)" mice (page 4) for multi cell patch clamp and "VIP-cre::LSL-TOM and SOM-cre::LSL-TOM" mice injected ...
8
votes
1answer
525 views

Why some cells don't produce purines?

It is said that erythrocytes, polymorphonuclear leukocytes and brain cannot produce purines. And the reason given as per this site is: Human brain tissue has a low level of PRPP glutamyl ...
3
votes
1answer
525 views

Why don't restriction endonucleases digest transformed plasmids?

In the textbook that I'm using, it explains that bacteria does not digest its own chromosomal DNA because the sites that would be cut by its own endonuclease are methylated. Is there a similar ...
1
vote
0answers
20 views

College Genetics: Xist vs. transposon

I'm taking introduction to genetics and I'm trying to understand the following question: Lets say there is a male cat with blue ears, a single gene mutation called BLU. We try to obtain pure bred ...
0
votes
1answer
60 views

How can DNA profiling be used to determine the number of organisms from a specific species that is within a certain area?

Here is the tedious exam question that asks this: question 8(b). https://drive.google.com/drive/folders/0B23NLD5L6099VWJya3dfLVJpbmc The question states: In 2007, the brown bear was a threatened ...
1
vote
0answers
41 views

Human Papillomavirus E7 (HR HPV16)

So there's a protein that binds to E7 viral protein, I want to remove a sub domain of the protein to see which exact domain the E7 binds to. What is the procedure for this? Edit: I believe the virus ...
1
vote
0answers
344 views

Understanding PAM and BLOSUM matrices

This question might be silly but I need some clarification. I'm slightly confused about if there are multiple PAM and BLOSUM matrices? Is there a different matrix for each sequence? My ...
1
vote
0answers
23 views

Are RNA transcripts always synthesised from the same DNA strand? [duplicate]

The DNA is read 3'->5' (and RNA synthesized 5'->3'). But due to the DNA strands having to be complementary, it seems to me that the origin can only appear on the correct side of the ORF on one of the ...
4
votes
1answer
283 views

Do telomeres appear at just one end of the chromosome?

I have just studied DNA Replication for my Biology Class and I have this question that leaves me stuck, though I have tried to figure it out myself. During telomere replication, I am aware Telomerase ...
3
votes
0answers
195 views

How would circular dominance of alleles be determined on the genetic level?

The distinction between dominant and recessive alleles seems to be due to loss or gain of function in the proteins they code for. Alleles have been observed exhibiting incomplete and hierarchical ...
3
votes
1answer
411 views

Meaning of ‘NC number’ associated with a gene?‘

Genes in listings etc. often have a number of the type NC_000012.12 associated with them. How should this be interpreted?
2
votes
0answers
31 views

Is there any technique can quickly expand one set of cell chromosomes?

Assume a cell type is very scarce while isolated out and hard to expand in vitro, and I wanna have more of its chromosomes, is there any technique , in vivo or in vitro or ex vitro, any would count, ...
3
votes
1answer
503 views

What are Expressed Sequence Tags (EST)?

I read in an article that ESTs are partial or sub-sequences of cDNA. What are ESTs exactly? Which part of cDNA is cut in order to make ESTs? Why are they so instrumental in genomic research?
3
votes
0answers
25 views

Does Pre replication complex sit on both strands?

In case of prokaryotes, the ori site have a definite nucleotide sequence. Each ori site have 5 9base-pair consensus sequences and 4 non-consensus sequences. DNAa binds to both types of sequences with ...
5
votes
1answer
165 views

CRISPR/Cas9: What are the main differences between sgRNA and the Cr:TracrRNA ?

So from what I understand, in gene editing, the CRISPR vector expresses a small RNA sequence comprised of a small guide-RNA that is complementary to your target sequence. The sgRNA comprises a 20 Bp ...
0
votes
0answers
38 views

Why do triploid foetuses fail to develop properly?

Polyploidy in plants works with no adverse effects - however when humans have an extra set of chromosomes a whole host of developmental problems appear. What's the cause for this discrepancy - surely ...
4
votes
1answer
3k views

Are SNPs and alleles the same thing?

It seems to be quite difficult to find an answer to this. Are SNPs the same thing as alleles?
3
votes
1answer
3k views

Is the promoter region of a gene transcribed?

If the RNA polymerase attaches to the promoter region of the gene, would it form the initial mRNA portion soon after attachment by reading the promoter region? Or should it slide across the DNA then ...
3
votes
1answer
485 views

Is gene only the portion of a single strand which codes for a particular protein?

I know that gene is a segment of DNA that codes for a specific protein. But is it a segment of a single DNA molecule or a DNA duplex? The given image shows a section of a dsDNA. Source of image:...
5
votes
1answer
385 views

Are there knots in DNA?

This question may sound silly. How does it come that the DNA molecules are not totally entangled with time in the cell ? If I take long strings in a box and shake it, that would create knots, and I ...
12
votes
1answer
5k views

Is female the default sex in humans?

I was taught in school that female is the default sex in humans based on the following logic: Development into a human male requires the activation of the SRY gene in the foetus. If that doesn't ...
7
votes
2answers
293 views

Which DNA elements belong to the definition of a gene?

I see a lot of different DNA elements mentioned as part of a gene (talking about eukaryotes): The length of DNA following the promoter is a gene and it contains the recipe for a protein. (video) ...
1
vote
1answer
92 views

Transcription Factor expression level

Could someone explain me in detail what is meant by "TF expression LEVEL", what does it represent and how is it measured? This is for example used in figure 3 of this paper: A census of human ...
6
votes
1answer
181 views

Can translation ever occur without transcription?

This question is aimed mainly towards viruses with ssRNA, is transcription required, for the +ve strand RNA? If so, why?
2
votes
1answer
114 views

What if our whole body is made up of cancer cells? [closed]

Today I learnt in my biology class that cancer cells are immortal. That left me wondering what if our whole body is made up of cancer cells? Will that make us immortal? Is it possible or why is it ...
3
votes
1answer
327 views

How does salt concentration affect chromatin compaction?

I've read that the primary obstacle to the compaction of chromatin is the negative charge on the DNA phosphate-sugar backbone. This negative charge is slightly stabilized by the positive charges on ...
1
vote
1answer
387 views

Is nucleosomal DNA ever degraded?

A hallmark of apoptotic DNA fragmentation is the digestion of DNA into individual nucleosomes. In addition, in the following experiment that tried to isolate the components of the nucleosome, the ...
3
votes
2answers
6k views

What are housekeeping and constitutive genes?

I have come across two set of definitions which are not contradictory but different. From wikipedia: A constitutive gene is a gene that is transcribed continually as opposed to a facultative gene, ...
0
votes
1answer
440 views

Calculating chromosome number in meiosis: Why is the crossbreed between a fox and a dog (dox) sterile?

Given the following example/question (originally found here): I worked out the haploid number of the dox to be 29 and the diploid number of the dox to be 58. 58 is an even number, so surely 29 ...
3
votes
0answers
43 views

psbA-trnH intergeneteic spacer inversion

What kind of software tool would you recommend as best suited to detect psbA-trnH inverisons? I have 1x coverage Sanger .fasta files and >2000 sequences, with 1 sequence per species. Most tools I have ...
1
vote
1answer
34 views

Changing genetic code of E. coli to accept synthetic amino acids?

I read in my Biology textbook that an experiment has been done in which one of E. coli's stop codon has been altered to accept a synthetic amino acid. I do not get how it can be done. Taking the ...
3
votes
1answer
255 views

What is the purpose of two cell divisions in meiosis?

At the moment, my thoughts are that the two cell divisions are necessary for recombination to occur, although I am not sure. I cannot really see why technically, the chromosome from each parent cannot ...
4
votes
1answer
3k views

Why are most mutations recessive? [duplicate]

Why are most of deleterious mutations recessive in nature? I understood that if it's recessive then one reason may be that the mutant gene doesn't code for a functional protein and so there is no ...
3
votes
0answers
143 views

Question about genetic recombination

I am having some difficulty understanding a few things about genetic recombination, in part because of confusion from different diagrams in books. First of all, I wanted to verify whether I have ...
1
vote
2answers
849 views

Why should you use an annealing temperature about 5°C below the Tm of your primers?

Why should you use an annealing temperature about 5°C below the Tm of your primers? According to my current research, I think it has something to do with the other reactents in the PCR, but I am not ...
-2
votes
1answer
42 views

Which analytical techniques could you use to research relationships between 2 proteins? [closed]

Two of the proteins I am researching are known to interact. However, I would like to know if they interact with other proteins as well, and possibly form a pathway. Which analytical technique(s) I ...
1
vote
1answer
157 views

What is the space between -10 promoter sites and start sites (+1) [closed]

Between the transcriptional start site of a gene and the -10 promoter region there is always a space of around 10 nucleotides, what is this space function and purpose? Do you see the space between ...
2
votes
0answers
32 views

Validity of comparing gene expression levels between alive and <24h postmortem cohort

There is a recent paper about assessment of a suicidal risk in psychotic patients https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4759104/ One of the important points is that the authors compare gene ...
1
vote
0answers
114 views

Why is the total length of Introns greater than the total length of exons?

I have just been reading that typically the total length of the Exons of a split gene is very much smaller than to total number of its Introns. Could anyone please explain why this is the case if its ...
4
votes
2answers
8k views

What is the role of tracrRNA in CRISPR-cas9?

From what I understand, in a CRISPR cas9 complex, gRNA is comprised of tracrRNA and crRNA. I've read that crRNA is the part which is matched to the DNA which is targeted, but what role does tracrRNA ...
0
votes
2answers
748 views

Do all polygenic traits involve epistasis?

Consider the following statement All polygenic traits involve epistasis. I think its true because polygenic traits involve several genes interacting together to result in a certain phenotype and ...