54 votes

How does a gene "know" what to change to?

Using your example, the gene doesn't know anything. Mutations cause some of the offspring of the red frog to turn green, some to turn blue, some to turn fluorescent yellow, and some stay red. Birds ...
iayork's user avatar
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36 votes
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Specific mechanism behind lethality of yellow coat color in mice

Really interesting question: The lethal yellow mutation (also abbreviated Ay) affects the agouti signalling protein which plays a major role in pigmentation. Heterozygous expression of it leads to the ...
Chris's user avatar
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14 votes

Can a blood type O be born from AB and A parents?

The ABO blood type is controlled by a single gene (the ABO gene) with three types of alleles inferred from classical genetics: i, IA, and IB. The IA allele gives type A, IB gives type B, and i gives ...
KaPy3141's user avatar
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11 votes

Can I use multiple bicistronic RBS sequences in a synthetic biological circuit?

That’s a great question and has lot of opportunities to explore. I am not sure anyone has followed up on this original BCD work systematically. We did try cloning these elements on a medium copy ...
Vivek K Mutalik's user avatar
9 votes
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Do any RNAs directly inhibit transcription

Yes there are reports of RNA directly inhibiting transcription. RNA induced transcriptional silencing (RITS) is a well known pathway in Schizosaccharomyces pombe (fission yeast). Initial ...
WYSIWYG's user avatar
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6 votes
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Left-handedness and Right-handedness - Are they genetic?

Handedness has, like many traits, a non zero heritability. You now should read the post Why is a heritability coefficient not an index of how “genetic” something is? to understanding what heritability ...
Remi.b's user avatar
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6 votes

Relative abundance of transcription factors and protein kinases

Summary The abundance of protein kinases and transcription factors vary among and between these broad classes of protein. General Considerations Let us first think what might be expected for the ...
David's user avatar
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5 votes

Is the increased/decreased enzyme activity (tyrosinase) caused by an environmental factor (UV radiation) considered to be gene expression?

Unless there's a feedback mechanism shutting off gene expression (which controls the proteins made by a cell), activation or deactivation of an enzyme is not in itself a matter of gene expression, it'...
anongoodnurse's user avatar
5 votes
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How much time do the different mechanisms of gene regulation need to take effect?

People often imprecisely say that type of regulation takes place on the order of many minutes to hours, and that may be as precise as you can get given the variable kinetics of any given pathway. ...
Jory's user avatar
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5 votes
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Why are most mutations recessive?

It is a bit ironic that you phrase your question with 'in the first place'. There is a parsimonious explanation for the effect: Dominant deleterious variants are quickly removed by purifying selection ...
AlexDeLarge's user avatar
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4 votes

Redundancy of the genetic code

You are correct in saying that Crick, in his Wobble Hypothesis, proposed that “the base on the third position of the codon and that on the anticodon need not be complementary”, but the “need not be” ...
David's user avatar
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Is the increased/decreased enzyme activity (tyrosinase) caused by an environmental factor (UV radiation) considered to be gene expression?

Since @anongoodnurse already nicely covery the effects of UV radiation on the cellular level, I will only have a look on the molecular level. UV radiation of the skin causes increased DNA damage and ...
Chris's user avatar
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4 votes

Can Blood Types Change?

Blood group antigens are either sugars or proteins found attached to the red blood cell membrane. ABO blood group antigens are the most clinically important antigens because they are the most ...
Sarannya E's user avatar
4 votes

How does a gene "know" what to change to?

Each offspring's color is a bit different from its parents. Some colors help the frog survive, other colors tend to get it killed before it reproduces. Over time, the species tends toward a color ...
Jon D. Moulton's user avatar
4 votes

How does a gene "know" what to change to?

Of course, as you know, a gene does not have any conscious, a gene does not know anything. It is all just a bunch of chemical reactions. Central dilemma First, you have to understand that a gene is a ...
Remi.b's user avatar
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4 votes

How does a gene "know" what to change to?

Another fun example is a certain type of moth that used to live in Western Germany ("Ruhrpott") and other areas during the Industrialisation. Its main habitat are birch trees, i.e. mainly white tree ...
AnoE's user avatar
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4 votes
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Is it possible to artificially select for flight in pigs?

Intro course to evolutionary biology I doubt you can get much from the below answer. At the end of the day, the only thing that would really allow you to increase your knowledge is probably an intro ...
Remi.b's user avatar
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4 votes

X linked traits expression in females

Because in different cells different copies of the X chromosome might be inactivated. So, in (approximately) 50% of the cells you will have the X carrying the normal gene activated, and in the ...
Fabio Marroni's user avatar
4 votes
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DNA methylation and the validity of the definition of epigenetics

A methylated nucleotide is the same nucleotide, for the purposes of base-pairing events. The methylated base will be paired with its Watson-Crick opposite after replication, for instance (and ...
Alex Reynolds's user avatar
4 votes
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Quantifying Gene Expression

What is Protein Expression Level? This was the original title of the post, which I edited myself because I regard the answer as trivial, but the question as more substantial. To deal with the trivial ...
David's user avatar
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4 votes
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Why do genes, encoding the same proteins and in the same conditions, have different expression?

If I understand your question and graph correctly, your Y-axis is log(x/REF), where REF is some external standard. Your "Ref" on the x-axis you expect to be the same as REF, so that log(Ref/...
Bryan Krause's user avatar
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4 votes
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Forward or Reverse Strand: Is there a difference when encoding genetic devices?

First, I think you have misunderstood the concept of sense/antisense. These are defined individually for each gene, with the sense strand always referring to the coding (non-template) strand of a gene,...
gaspanic's user avatar
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4 votes

Function of SMAR in plasmids?

S/MAR (nuclear scaffold/matrix attachment region) Is a DNA sequence pattern that recruits the nuclear protein hnRNP-U/SAF-A a multifunctional scaffold/matrix specific factor. Jenke et al. 2002 ...
markur's user avatar
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4 votes
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What is the minimum Ct value that you would consider indicates no gene expression?

Can't you just do a negative control and use that to calibrate? Alternately, run the DNA from your PCR on a gel with a positive control indicating expression. Literally zero expression should mean ...
Maximilian Press's user avatar
3 votes

What is a cognate enhancer sequence?

Cognate means of common origin. In molecular biology, cognate is used to refer to known interacting pairs of functional entities. For example, cognate receptor of a ligand means the primary (default) ...
WYSIWYG's user avatar
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3 votes

How to put a gene under the control of a regulable promoter?

If you're expressing the gene in E. coli, then you're almost certain to be using a plasmid or other ectopic gene vector. There are a wide variety of plasmids available, with many different promoters. ...
Forest's user avatar
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3 votes

Genetic expression in interspecific hybrids

Davis et al. 2015 studied hybrid sterility in cats by identifying SNPs and transcriptome changes that are associated with hybrid male sterility. They identified eight autosomal regions "involved ...
markur's user avatar
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3 votes
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How do biologists quantify "gene expression" in experiments?

The primary product of protein coding genes are mRNAs. When we talk about measuring gene expression we want to assay the steady-state levels of a specific mRNA within a cell. This is usually ...
mdperry's user avatar
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3 votes

What is the role of TATA box in transcriptional regulation?

TATA box serves as a binding site for the TATA-binding protein (TBP; and its associated factors, together comprising the TFIID). TATA-box is one of the basic promoters present in many genes and ...
WYSIWYG's user avatar
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3 votes

Does a zygote express all genes?

The short answer is that no, a zygote doesn't express all genes simultaneously. A zygote is like any other cell, in that it represents a distinct phenotype. And like any other cell, this phenotype ...
Forest's user avatar
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