Questions tagged [molecular-genetics]

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

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Absent gene expression from one of two vectors co-transformed into the BL21(DE3) strain of E. coli

I've been trying to express two proteins in the BL21(DE3) strain of E. coli. One gene is in a pCR2.1 vector and the other in a pET-expression vector. When I induce with IPTG and run on an acrylamide ...
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How are Viruses Genetically Modified?

Okay everyone, so I get that you can perform lysis on a bacterium to extract the plasmid, then alter the plasmid using restriction enzymes and ligase, and re insert it back into the bacterium with ...
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Open Reading Frames vs Coding Sequences (CDS), are they different?

The two terms confuse me for a long time. What is the difference between ORF and CDS. Some people say ORF could contain intron and CDS does not. The wikipedia definition of ORF does not contains ...
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Expression of eukaryotic ribosomal DNA

The Wikipedia page for rDNA says "Ribosomal DNA (rDNA) is a DNA sequence that codes for ribosomal RNA" Also, the figure next to it says "The gene segment of eukaryotic rDNA contains 18S, 5.8S, and 28S ...
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Is one DNA molecule same as one chromosome [duplicate]

Is one DNA molecule = one chromosome or is one DNA molecule = all the chromosomes, ie, all the genetic material in our cells? I have googled it but I am not getting clear answers ?
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How to calculate the quantification of qPCR to the equivalent of the number of nuclei in fungi?

I have a question about the quantification through qPCR. The my question is: if I made the qPCR of a fungal functional gene, how is possible to obtain from the quantification number (in nanogram) the ...
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How does an antisense RNA molecule restore protein function in CF patients?

I am researching a treatment for cystic fibrosis (CF) called Eluforsen and I am trying to understand the mechanism by which an RNA molecule can restore proper protein function. In many research ...
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How do I identify and then isolate a Gene that codes for a particular observable phenotype

How do I identify and then isolate a Gene that codes for a particular observable phenotype. It is a novel bacteria and I do not know the gene sequence or the protein that it codes for.
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Is the total of all human DNA (23 pairs) the longest of all species?

The human DNA molecule is about 2 meters in length. See here. We have 46 of them, so in total 82 meters. In this article it is said that the genome of the Protopterus aethiopicus (a.k.a The marbled ...
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Are all carcinogens mutagens?

I assume that all carcinogens must be mutagens, but I've read that this is not the case. However, I can't find any good examples or an explanation of why it is not the case. How can a non-mutagenic ...
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Can bacteria pick up lethal plasmids?

I am sorry if this question is too general, and does not have any concrete answer. I was explaining to my non-biology-background friend about plasmids and how they are picked up by bacteria from the ...
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How does a lymphocyte produce an antibody from an antigen?

I am studying the immune system, and I have a question about the inner workings of antibody production in lymphocytes. As I understand it now, lymphocytes are able to create antibodies based on ...
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How do mutations of viruses lead to drug resistance?

For instance, after starting zidovudine monotherapy against HIV, resistance develops against the drug because of a point mutation in the RNA transcriptase enzyme to which the drug binds. So how does ...
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What prevents mRNAs that are localized to a specific part of the cell from being translated before they reach their destination?

One of the methods of mRNA localization, for example, is random diffusion of mRNAs where the mRNA binding proteins are localized to a certain part of the cell. However, I was taught that the ribosome ...
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Parthenogenesis vs. Fertilization. Is a polar body different from an egg?

In Parthenogenesis that happens by automixis "the replication of an egg by meiosis and the transformation of the haploid egg to a diploid cell occur by fusion with a polar body." =https://www....
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How do cis-regulatory elements and trans-regulatory elements behave differently?

Suppose you are working with an operon in a diploid organism. I'm looking for either a biochemical or genetic explanation. What I'm having trouble with mainly is understanding how something would ...
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How do homologous pairs find each other

If I'm not mistaken the only time homologous pairs of chromosomes need to find each other is during gamete formation in preparation for crossover recombination. How do they find each other?
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Prokaryotes Genome

What function of repetitive sequences of Prokaryote? I see a gap (intergenic region) between 2 coding strand. But just only a single origin region in Prokaryotes. How it can transcription coding ...
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How can we say that a gene is spacio-temporally regulated?

Gene expression is depending on the space and time of the cell. How can we distinguish the function of a gene without a chance of changing its expression? And also how is it possible to find the exact ...
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What controls specific gene silencing during cell differentiation?

I am intrigued by the fact that all cells of our body use the same DNA. How do the cells differentiate during the post fertilisation divisions? I read about gene silencing, which can be an answer to ...
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Study on Introns?

I am curious whether there has been a study done on the effects of removing introns. Specifically, what happens if you genetically edit a eukaryote genome to no longer contain introns? Or maybe just a ...
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Methods: Homologous recombination and retroviral infection

I'm looking for a textbook that explains these methodologies: Use of homologous recombination to insert a gen-cassette into another organism's gen. Use of retroviral transduction to deliver genes ...
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During DNA foot-printing, what is the purpose of radioactively labeling only one end of the DNA fragment?

I read that during DNA foot-printing analysis, DNA is radioactively labeled on one end before being cleaved by DNase 1. I understand that it is labeled so in order to locate the fragment on a gel, but ...
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what is minimal promoter and what is basal promoter?

what is minimal and basal promoter and what are their elements and what is the difference between the two?I'm confused. searched a lot, but didn't found any satisfactory answer. please help
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What causes the elongation of Genome down the evolutionary time line [closed]

Theory of natural evolution says that complex life forms arose from simpler ones e.g. starting from Eubacteria to modern day multicellular eukaryotes. {If we try to reduce these changes happening at ...
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How many recombinations occur in an average human chromosome?

And is it a different number depending on which chromosome we choose (disregarding the change of this probability due to the differential size of the chromosomes)?
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What Ultimately Controls DNA Transcription?

Transcription of DNA and further splicing of mRNA is regulated by various transcription factors, small nuclear RNAs and so on; similarly such related mechanisms as transposition of transposons. All ...
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Difference Junk DNA and Pseudogenes [duplicate]

1-Are Pseudogenes and Junk DNA both Non-Coding DNA or they are different entity? How much Pseudogenes & Junk DNA do we have respectively? 2-I read that Non-Coding DNA has functions, my question ...
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Question about alternative polyadenylation

I know that alternative polyadenylation creates different transcript isoforms. My question is whether alternative polyadenylation ever results in differences in the terminal/last exon? The only case I ...
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Is the genetic term “polycistronic” still used in modern biology?

Is the term "cistronic", meaning an ORF on a mRNA, still commonly used in modern genetics? I´ve seen "polycistronic" being applied to prokaryotic mRNA in old textbooks, but I´ve rarely stumbled upon ...
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Can different cell lines of same type symbolise samples from different patients in ChIP-seq?

Can I simulate different patients by using different cell lines of the same cell type and from the same tissue? Can I also study apoptosis in an immortalised cell line? I have a gene X (transcription ...
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Confusion about result of monohybrid cross in Mendelian genetics

I was studying monohybrid crosses in genetics where the character considered is stem height. Whenever I came across punnett squares, I used to calculate the probability of the genotype of the ...
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What advantages could there be for using the unseen variant chosen by He Jiankui instead of the naturally occurring CCR5-∆ 32 mutation?

Jennifer Doudna mentioned in https://youtu.be/9Yblg9wDHZA?t=2566 on 2019-02-21 that He Jiankui introduced an unseen variant of the CCR5 gene when gene editing the twin humans Lulu and Nana. What ...
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How evolutionarily conserved are UTRs?

Coding sequences of genes have a certain degree of evolutionary conservation, so that comparisons based on sequences (BLAST, HMMER etc) can be informative. Generally speaking, the more two species are ...
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Can Cas13 be used with multiple crRNAs in the same reaction?

CRISPR-Cas13 equipped with crRNA (complementary to transcripts of interest) can be designed to target ssRNA transcripts in cells. Upon successful crRNA and ssRNA binding, a fluorescent domain on ...
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How to determine if two mutations in a gene are on the same or different alleles?

I would like to know, except a familial study, is there another way to determine if a mutation/variation is cis or trans (i.e. on the same or different alleles)? For example by sequencing technique or ...
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Number of DNA strands per chromosome

As I was reading Griffith's Introduction to genetic analysis this evidence was provided for single DNA makes single chromosome. Eventually geneticists demonstrated directly that certain chromosomes ...
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What is the difference between DNA vs RNA Editing in the context of gene therapy?

As a someone with beginner knowledge on biology, I have come across the terms "RNA editing". Take this paper for example : RNA Editing with CRISPR-Cas13 From my understanding, DNA -> RNA -> Proteins ...
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Need help in identifying and understanding the origin of an expression variant

We usually denote the origin of a mutation as either somatic or germline. This information is usually available in certain databases such as CIVIC, ClinVar, COSMIC etc. But when we come to variants ...
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Are epigenetic modifications the most stable mechanisms for cell differentiation?

Wondering what the general take is on what are the molecular mechanisms that are mostly responsible for cell type differentiation stability; ie, for a cell's identity to actually become 'locked in' ...
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Are all fusion genes somatic in origin or can fusion genes be germline?

Fusion genes should have an origin.These are essentially hybrid genes that are translocated in its entirety. Eg. BCR-ABL, EML4-ALK are known to be implicated in cancer pathogenesis. Do these ...
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Can DNA be flattened?

DNA is always shaped like a double helix. But could you flatten the double helix (which is essentially just a twisted ladder) and would DNA still be able to duplicate and control cells?
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What is the difference among biochemistry, molecular biology, molecular genetics and structural biology?

I have never heard of straigthforward definitions of these fields in my college lectures, and the Internet searches were not very helpful. However, from what I have learned at different subjects, this ...
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How does the difference in the sequences of a dominant and a recessive allele of a gene help in the expression of the gene? [duplicate]

When an organism is heterozygous at a specific locus for a gene and carries one dominant and one recessive allele, the organism will express the dominant phenotype. These alleles vary in their ...
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Computational approaches for making hypotheses about the effects of genetic engineering? Experiment planning methods?

Let's assume that I am searching for gene editing candidates for curing human adiposis. Are there computational frameworks that can allow me to select the best candidate-genes for editing via some ...
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Is complete dominance actually a genotypic process?

An example often stated for codominance is blood groups, where both alleles version of the protein is expressed and can be found in the cell membrane. An example of incomplete dominance often given ...
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Are mitochondrial genes decoded in the same way as nuclear genes?

Mammalian mitochondrial genomes contain only 22 tRNA-coding genes, which is an insufficient number to decode mRNAs under the standard wobble rules. How is translation of mitochondrial mRNAs achieved ...
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Selective breeding fluorescent sheep - possible?

I got into a small argument :-) Friends of mine try to draw fat line between "natural" selective breeding and applying molecular biology (CRISPR/Cas9) to put new traits in existing species. The line ...
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Increase rate of change in coding regions?

If a sequence is under selection will it acquire more changes over time because of faster fixation than if changes were neutral? Is this true or am I missing something?
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Why are Barr Bodies usually seen along the edge of the nucleus under the light microscope?

We do a typical class exercise of aceto-orsein staining of buccal epithelial cells from female students to visualize Barr bodies under the light microscope. All the illustrations and pictures in the ...

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