The process by which information encoded in a gene is converted into a functional protein or RNA, resulting in or contributing to a phenotype.

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How many copies of a gene?

I am studying mathematical models of transcription and translation and I am wondering: In a particular genome, how many copies of a gene coding for one particular protein should one expect? Are they ...
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1k views

How can CI repressor both activate and repress $P_{RM}$ promoter found in $\lambda$ phage?

I'm reading a paper where the authors constructed a toggle switch that uses bidirectional $P_R/P_{RM}$ promoter found in the $\lambda$ phage. There are 3 binding sites - $O_{R1}$, $O_{R2}$, $O_{R3}$ - ...
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566 views

Negative value on linear gene expression in microarrays

I am starting to use microarrays and maybe this is a dumb question: Using Illumina microarrays, linear gene expression can be negative? Or maybe some artefacts have been introduced? And, in this ...
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62 views

What is meant by “alien” probe in a microarray?

In my lab we did a microarray to analyze differential gene expression in S. cerevisiae treated with UV irradiation. We are now analyzing the results and one of the up-regulated genes is labeled "...
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236 views

Why do some protocols require prewarming a liquid medium before inoculating?

For example, in this protocol for E. coli competent cell preparation, it says: Plate 10 uL E. coli BL21(DE3) cells on a LB-agar plate; incubate overnight (12 hours). Prepare 500 mL SOB medium ...
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162 views

Redundancy of the genetic code

One particular codon codes only for one amino acid, but an amino acid can be coded for by several different codons. Now according to the genetic code, the codon UUU ...
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854 views

which exact mechanism triggers the first cell differentiation after n divisions?

I would like to understand which mechanism triggers the first cell differentiation after n divisions. I read previous articles on SE and Wikipedia articles on cellular differentiation and ...
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232 views

Can intron become exon in alternative splicing?

From this image We can see several exons that are actually introns in other genes. It's not a really a different gene, it's an alternative splicing of a gene. My background is not biology so is it ...
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227 views

Epistasis Across Chromosomes and Individuals 'Homozygous for Interactions'

Apologies for any failures in nomenclature. I'm a mathematician who is making a foray into genetics for a masters thesis. Specifically, I'm generating artificial diploid genetic sequence data and ...
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66 views

Is it possible to elicit transient gene silencing by using virus induced gene silencing (VIGS) in plants?

I am looking for a molecular tech' which could result in transient gene silencing in plants. The objective is to not make transgenic plant, but to use these tech' to silence a gene of interest for a ...
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106 views

Combining gene expression data from two species

I currently have two sets of gene expression data. The first is a dataframe of genes identified by Annotation id CG numbers (for example "CG10005") in one column and a numerical variable of interest ...
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66 views

Where can I find histograms and tables of prevalence of mutations in cancer?

At some point in the past I found a cancer portal site which had aggregated data for the relationships between various mutations and their prevalence in cancer types and tumor data. The data was ...
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52 views

Is it possible to express the cistrons from a polycistronic insertion fragment in a single plasmid?

I have a insertion fragment that I wish to express from pUC19 in Escherichia coli. The insertion fragment is a sub-section from a larger operon sequence and contains just the last two cistrons from ...
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115 views

Genetic Imprinting and Cell differentiation

It does not seem possible that these two processes can coexist: 1) Genetic imprinting is the phenomenon where genes are expressed differently depending on the parent of origin: 1a. Methylated ...
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42 views

What are the effect of microtubule or microfilament inhibition on yeast expression profile?

I was wondering whether anyone has looked at what are the expression changes in yeast when the microtubule or the microfilament polymerization is inhibited? Have there been whole-genome studies?
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644 views

T7 promoter leakiness

Can a gene be expressed under the T7 promoter in an E. coli strain (e.g. DH5 alpha), which does not have the T7 polymerase gene encoded in its genome? In other words, is T7 promoter leaky? To be ...
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51 views

Mechanisms of genotype*sex interactions [closed]

I'm looking for suggestions of the mechanistic level at which genotype*sex interactions can occur. These give different phenotypes from the same genotype dependent on the sex they are expressed in. ...
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1answer
709 views

meaning of the “reads” keyword in terms of RNA-seq or next generation sequencing

I'm an undergraduate student at computer science and currently, I'm interested in bioinformatics. Today, I've started to read a paper about clustering and classification of non-coding RNAs can be ...
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60 views

What is the most appropriate way to normalize gene expression data?

This question comes because reading a paper about normalization of gene-expression data, is not clear if the method for normalize the data is just for RNA-Seq data or could be applied also for ...
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1answer
138 views

Could fingerprints potentially be changed using a gene gun?

Not to confuse with your "DNA fingerprint" I've read surgery is readily used to not just remove but even to change people's prints through employing very small grafts between opposing hands. About 5 ...
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201 views

How to determine the direction of regulation of a gene by comparing gene expressions?

I am just learning about the gene expressions and regulation. Several researches focus on finding the genes of altered gene expressions on a microarray to claim that they have a correlation to a ...
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60 views

Mutating a protein without mutating the gene?

Is it possible to mutate a region of a protein (says about 300 amino acids long) without actually mutating the gene? One possible way that I can think of is to use RNAi and specifically block that ...
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1answer
62 views

What is meant by “the degree to which a gene is expressed” in an individual?

Here is an excerpt from a text that I was reading, Here is an example of microarray data. The idea is to take a group of different individuals and for each of them, you measure how much they ...
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119 views

Sex biased gene expression in the X chromosome

It has been shown that the X chromosome is frequently enriched for female biased genes, and has a deficit of male biased genes. For example in this paper, and this one. However, I'm struggling to ...
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1k views

Optogenetics - How do microbial opsins work?

I'm just introduced to the optogenetics method and am having some trouble grasping the genetics (of the optogenteics) part of things. So we have Retinal and Opsin that form Rhodopsin molecule that ...
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45 views

Why introduction of an extra copy of a gene related to pigmentation causes RNA interference in Petunia?

RNAi became famous after Fire and Mello experiment in C.elegans; however, it had been observed before. In the 80's, Jorgensen was trying to increase pigmentation of Petunia flowers by introducing ...
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109 views

IPTG and lac operator with e coli for foreign gene question

We did an experiment were we have e coli with a plasmid with a gene from another bacteria in it, and we put in IPTG in for induction. Will after looking up more about IPTG online I see it's related to ...
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85 views

What does it mean for the signals for transcription and translation to be “conserved”?

I was reading this article: "Overview of vector design for mammalian gene expression." for an explanation of why mammalian cell lines are used for expressing cloned genes, and one of the reasons ...
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2k views

Where to put the gene after eukaryotic promoter for best expression levels?

As far as I know there is an optimum distance between a promoter and the gene for the best expression levels. What is that distance for common promoters like CMV, SV40? If you have a first hand ...
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36 views

Are all genes transcribed in differentiated cells?

My textbook tells me that it’s specific transcription factors that allow for a different set of genes to be expressed in different cells (differential gene expression). My book gives the example of ...
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93 views

Data analysis of transcriptome sequencing data [closed]

I want to learn more about the data analysis and statistics on transcriptome sequencing data. I would like to read some important papers of the field and books and maybe some MOOCS, if they are ...
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124 views

Could miniaturization be used to protect endangered large species?

In some animals (like dogs) size seems like it's controlled mostly by just a few genes (IGF1, and the genes that repress it). I'm curious: (1) Does other miniaturization takes a similar route (for ...
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299 views

In which phenomena does one gene pair hide the effect of other unit?

This question was asken in an exam, The answer they are saying is "Epistasis". But I think "Dominance" fits better, because it is not mentioned whether genes of same allele are to be considered or ...
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36 views

What network motifs or other mechanisms can make the expression of a gene invariable to the environment?

Next to double positive feedback loops and chromatin modification, which other mechanisms can make a gene susceptible to a certain environment in one cell-type but not in another?
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1k views

Why does the pET- expression vector contain a LacI gene additionally to the one in the genome?

The pET plasmid is used for protein expression with T7 promotor in expression strains, such as E.coli BL21(DE3) It contains a lacI gene which codes for the lac repressor protein, a protein of ...
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139 views

Expression of bidirectional promoters

How are bidirectional promoters expressed ? (Won't RNA Pol have to go in 3'-5' direction?) Why are they more commonly found in eukaryotes than prokaryotes?
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49 views

What is the role of TATA box in transcriptional regulation? [closed]

I know what is the TATA box, but I wish to know whether it has specific roles in transcriptional regulation.
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1answer
66 views

Are dogs affected by dwarfism?

My husband and I noticed a dog today that looked like a smaller version of a purebred Border Collie, although it didn't appear to be a puppy. It made us wonder if other animal species experience ...
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110 views

Correct/complete representation of RTPCR statistics

In papers reporting a relative quantification of gene expression by RTPCR, I often see a bar chart with mean ± standard error or deviation, with the deviation belonging to biological replicates. This ...
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1answer
127 views

How does alternative splicing work?

I am trying to find out what controls what exons are spliced out, and I keep coming across the term cis regulator, but I cannot seem to find a clear explanation of what happens... Thank you in ...
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1answer
830 views

What are microRNA, siRNA and antisense RNA?

From what I understand, microRNA binds to proteins which can cut certain mRNA strands do that this protein is not synthesised. This seems like gene silencing to me, however I have also come across the ...
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516 views

Why do our epiphyseal plates close up in our late teens or early twenties?

What causes our epiphyseal plates close up in our late teens or early twenties? I realize that one's genetics plays the main role in this. I assume there is a gene that controls the epiphyseal plates ...
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545 views

Using RNA-seq to compare gene expression across patients instead of between Control and Experimental conditions

I am working with RNA-seq data from the Cancer Genome Atlas TCGA and I have been reading about how people have compared gene expression levels measured by RNA-seq. Many of the papers I have read talk ...
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826 views

Promoter in the lac operon

Here is the question: Suppose an experimenter becomes proficient with a technique that allows her to move DNA sequences within a prokaryotic genome. If she moves the promoter for the lac operon to ...
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50 views

What is mRNA expression level?

I cannot find clear explanation of what is mRNA expression level, and how to measure it. I would appreciate if someone explained it or gave a reference. Thanks!
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4k views

Why is the function of lacA (encoding thiogalactoside transacetylase) not clearly understood?

It's almost half a century since the lac operon was discovered but isn't it weird that the precise role of transacetylase isn't clearly understood ? Here a wikipedia article with a link to a journal ...
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1answer
522 views

How can a continuous RNA be transcribed in the lac operon?

The lac operon has 3 genes: lacZ , lacY and lacA. I have seen that the m-RNA transcript of these genes has stop codons in between. So, how can the RNA be made continuously? Won't the RNA Pol detach if ...
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1answer
94 views

Confusion related to a term probe-by-background interaction

I was reading a paper related to bioinformatics where it uses the drug response on the cancer cells and the gene expression of the individual cells are studied to find any useful insights. Specially, ...
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293 views

One flybase gene number (FBgn), many Affymetrix Id's

I am trying to convert a set of Affymetrix ID's, like this one 143053_at_3745, to Flybase Gene Numbers (FBgn) like this one FBgn0000015. I have downloaded the Flybase file required to do so (as ...
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70 views

variation in expression accounted for a SNP — what's a usual percent?

I am reading a GWAS paper that found a SNP associated to predisposition to colon cancer and was assessed for gene expression of the nearby gene. They found that the genotype accounted for 55% of the ...