Deoxyribonucleic acid (DNA) is the carrier of genetic information, including for all known living organisms. The only known exceptions are RNA viruses.

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Why does all life use the same macromolecules in their genetic code?

There is no biochemical constraint of any sort, so why doesn't some other code work? Why is it specifically RNA/DNA?
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Complexity in creating transgenic animals (e.g., mice)

Many papers I have seen describing transgenic rodent models (and presumably applicable to other model organisms) involve the knock-in, or modification to, a single gene, possibly two genes. With ...
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1answer
374 views

Solubility of DNA in water

This would seem to be an easy to answer question, but I was unable to find an answer (in g/L) for generic double-stranded DNA or plasmid neither on Google nor on BioNumbers. I would expect the ...
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2answers
31 views

Are genes on the 5' to 3' strand only?

I confused myself during studying, and wanted to confirm something. Since transcription via RNA polymerases only takes place in the 5'to 3' direction, that would mean that that 5' to 3' strand is the ...
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0answers
17 views

Relations of Watson & Crick work and Meselson & Stahl [on hold]

It is said that Watson & Crick postulated the DNA model,does this make Meselson & Stahl (which found out that DNA is semi-conservative) contributed to enhance the postulate by Watson & ...
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41 views

Organ donation compatibility based on DNA

As far as I know, multiple tests are made before organ transplant to determine matching. Would it be possible to do the matching based on the DNA of the patients, rather than the actual serum ...
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21 views

There are 6 classifications of CFTR mutations. Is a causal relationship to the sweat test known?

Cystic fibrosis (CF) is caused by mutations in the gene for the protein cystic fibrosis transmembrane conductance regulator (CFTR). The CFTR mutations are classified in 6 classes. The sweat test is ...
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0answers
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Diffuse DAPI staining after time in tissue

My student is using ProLong Gold with DAPI (premixed) on sheep uterine tissue. We have used this reagent for some time with great results. Now, when she finishes her immunofluorescence protocol, ...
3
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1answer
32 views

Are genes uniformly dispersed throughout the genome?

I think that telomeres and centromeres are regions with a very low gene content (= regions that contain few genes). To the exception of telomeres and centromeres, are genes uniformly distributed ...
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1answer
36 views

Why would mutation rates increase in a tumour?

This article describes a tumour: Swanton found that even the primary tumour was surprisingly varied. He found 128 mutations among the various samples, but only a third of these were common to all ...
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3answers
2k views

Which organism has the smallest genome length?

Which animal/plant/anything has smallest length genome?
3
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1answer
77 views

Is nuclear DNA immuno-privileged?

It is well known that if DNA occurs in the cytoplasm of eukaryotic cells, an immune response may be triggered through a myriad of DNA receptors and pathways as part of the immuno response. Yet, ...
3
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1answer
62 views

Specific numbers of nucleotides in Okazaki fragments

Okazaki fragments are formed during replication of the lagging DNA strand. What determines the length of these fragments?
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1answer
117 views

Why are nitrogenous bases of DNA hydrophobic if they can hydrogen bond?

Why are nitrogenous bases of DNA hydrophobic if they can hydrogen bond? Is it that they are only relatively hydrophobic? This forum explains it but does not give an example of the structure.
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1answer
24 views

Why can't this be 1st meiotic division non-disjunction as well?

The child has gotten 2 "sick" chromosomes from his dad and 1 healthy from his mom, leaving it with trisomy 13. I can see how this can happen in the second meiotic division of the father but I can ...
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8answers
2k views

Is there a biological mechanism for evolution encoded into our DNA?

Throughout high school, I remember learning about Darwin's theory of evolution as if it were near-fact. But something always seemed wrong about the ideas presented. Survival of the fittest Random ...
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0answers
40 views

What happens when a genome is shorter than the other? [closed]

Say there were 2 creatures of the same species. Creature 1 has a longer genome than creature 2, it may be just a few base pairs, but what would happen when the genes were crossed to create creature 3 ...
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2answers
85 views

What is the DNA Sequence for an apple?

The title says it all. I'm just curious. I read that scientists mapped the genome for Malus Domestica, but I can't find a sequence anywhere.If this is a stupid question, I would appreciate if you tell ...
7
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1answer
43 views

Evolution of the Redundancy of the Genetic Code

In short Looking at the genetic code, it appears that most redundancy is on the third letter rather than on the first or the second letter of the codon. Why has it evolved this way? Longer version ...
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1answer
65 views

Is each generation getting older? [duplicate]

So we know that our sperm and egg cells get set aside relatively early so that they aren't going through unnecessary cell divisions and causing DNA damage or telomere shortening, but since each new ...
2
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1answer
55 views

How semi-synthetic cell with artificial DNA works

I know that by now this is old new but I heard that a cell that used a synthetic pair of nucleotides, called X and Y, have been made. My question was, how did the cell understand the X and Y ...
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5answers
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Life without DNA?

I'm by no means an expert in the field, merely a curious visitor, but I've been thinking about this and Google isn't of much help. Do we know of any lifeforms that don't have the conventional ...
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0answers
29 views

Does bromophenol blue cause a shadow on agarose gels stained with SYBR Gold?

Bromophenol blue in loading dye is known to cast shadows/absorb emitted light signal from DNA on Ethidium bromide gels during imaging. But if SYBR Gold is instead used as the nucleic acid stain, does ...
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2answers
291 views

What makes DNA helical?

Why isn't DNA like RNA; why isn't RNA like DNA, that is, helical? Why are RNA chains straight?
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1answer
27 views

C Form DNA Base Pairs Per Turn

How does C-DNA have 9.33 base pairs per turn? The number of base pairs should be quantised. How can it be a decimal?
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Linear and Circular DNA

So school has taught us that eukaryotes have DNA that is linear and inside of a membrane - called the nucleus. And that prokaryotes have circular DNA that is free floating inside of the cell. We ...
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2answers
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Why do many DNA solutions contain additional compounds?

DNA solubility data in only water is scarce. A previous question asked for a quantification of DNA solubility in water. It seemed like it would be easily answerable, however isn't quite that simple ...
7
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1answer
126 views

What determines the number of chromosomes an organism carries?

This is an extension of this question about What limits chromosomal length?. I am wondering what could be the specific reasons behind the number of chromosomes an organism carries. In other words, ...
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3answers
123 views

Immortality Gene? Really? [closed]

I read somewhere in the internet and wondered if human genes have deactivated immortality genes locked somewhere in the DNA strand. Is this statement true? What does it mean for human lifespan?
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1answer
24 views

Which pair of primers should be used to amplify the ORF in PCR? [closed]

So I want to choose the correct set of pair of primers to amplify the ORF of the gene that corresponds to amino acids in a protein. The start and stop codons are underlined. (I know that these need to ...
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4answers
882 views

“Same” DNA vs genes

It is often cited that humans share 99% (or 98%) of their DNA with chimpanzees. On the other hand it is stated that siblings share only half of their genes. What (if any) is the difference between ...
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1answer
385 views

What does it mean to “map the human genome”

I know some elementary chemistry and biology. I also think I know what a gene is (it's a sequence of DNA which encodes a particular protein). I also know that on a chromosome there are sections of DNA ...
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1answer
2k views

Are human chromosomes connected or separate molecules?

Do the 46 human chromosomes form a single unbroken DNA helix? Or is it rather that a human's genome consists of 46 disconnected helices? If it is the former, does the common numbering scheme for ...
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3answers
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Is the size of the genome across species roughly the same?

Chromosome number differs across species. Is the amount of DNA comparable between organisms, just being split into smaller chunks in those species with more chromosomes? Or do species have different ...
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0answers
24 views

Is it possible that the DNA of an individual changes significantly over a period? [duplicate]

Is it possible that the DNA of an individual changes significantly over a period ?
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1answer
113 views

Restriction sites

I would like to know: how many restriction sites does a restriction enzyme use on a DNA molecule? In other words: If a sequence on a plasmid contains the following bases: ATTGCAGTCTG and I want ...
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35 views

How stable is linear DNA transfected in eukaryotic cells?

I would like to know, with references from the literature, what is the half life of a linear dsDNA transfected in a mammalian cells. For example, if I transfect human cells with a PCR product ...
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39 views

What is the fate of micronucleus DNA?

Micronuclei are cellular structures that are formed as a by-product of, usually, defective mitosis. The piece of chromosome in a micronucleus may, or may not contain a centromere and the DNA is ...
2
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1answer
71 views

Consequence of Plants as Incomplete Protein Source

Some years ago, in a 1000~ level biology course we learned that the DNA essentially encodes formulas for creating proteins from amino acids. While the human body can synthesize many many amino acids, ...
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1answer
38 views

X-recessive disorder pedigree confusing me

This is a pedigree of a family in which bleeder disease, an x-recessive disease, is present. I am asked which marker, A or B, the disease is linked to. I've asked about this type of problem before: ...
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1answer
42 views

Dynamic mutation and huntington's

I read that Huntington's is a disorder caused by dynamic mutations in the DNA, which means that a triplet sequence of DNA changes from generation to generation. Say we have the sequence ATGATGATGATG. ...
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1answer
49 views

Where to find gene manipulation video (or photos)

I hope Im not asking a dumb question! Where can i find video of gene manipulation in action under microscope? Like extracting a gene from a cell, fixing gene mutations, putting the gene in a vector, ...
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0answers
81 views

Do DNA supply houses maintain a watch list for dangerous oligos (Anthrax, Smallpox, etc.)?

The recent work by DeLoache, et al. on a synthetic opiate-precursor production pathway in yeast has generated a lot of scare stories in the media about people homebrewing heroin as easily as they ...
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3answers
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What is a genetic marker?

In DNA sequencing and analysis, what is a genetic marker? I've heard that microsatellites are genetic markers? Those are repetitive strands of bases such as GCAGCAGCAGCA etc. Why are they markers and ...
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2answers
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Chromosomal translocation notation

A reciprocal translocation is denoted for example: t(4;12)(q32;q24) indicating that q32 on chromosome 4 being swapped with q24 on chromosome 12 if I understand this correctly. My question is: How do ...
0
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1answer
28 views

X-recessive disorders and genetic markers

Please observe the following pedigree of a family with a x-recessive disease (bleeder disease). The A's are genetic markers so close to the disease gene that recombination is negligible. I ...
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1answer
38 views

Pedigree problem and type of inheritance [closed]

Please observe the following pedigree and come up with a conclusion as to which type of inheritance is most likely Now it should be obvious that it's either autosomal dominant or autosomal ...
3
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1answer
40 views

Gene frequency problem

1/330 of white people in south Africa have a disease called Porphyri. What is the frequency of the gene if it is inherited autosomal recessive? This one I understand. The genotype frequency is $q^2 ...
3
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1answer
62 views

Walk me through microsatellite markers and PCR

Three polymorph microsatellite markers are used to try and narrow down the location of a disease locus, with the use of PCR with 2 flanks on each side of the actual polymorphic area. The PCR ...
4
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1answer
70 views

Bayes theorem for mutations

MEN 2A is a dominant inherited disease caused by a mutation in the RET proto-oncogene. The probability of being sick when you have the mutation of the RET proto-oncogene varies with age and is assumed ...