Tag Info

New answers tagged

0

While physiological experiments could be conducted without organic solvents, chemical syntheses of DNA or analogs, chemical modification of DNA, and purification after chemical reaction could be performed in the presence of organic solvents. Such experiments are not directly relevant to physiology, but we use chemically synthesized DNA and DNA analogs. In ...


3

DNA in pure water. The only time that nucleic acids would encounter pure water would be in a laboratory setting--for example after an oligonucleotide is synthesized in vitro, the protecting groups are removed from the reactive atoms in the finished sequence and the final product is cleaved from the supporting matrix. At that point you can lyophilize ...


1

First of all, if this is a homework question, add that tag to it. And show what work you have done so far. Secondly, primers for amplifications should lie on opposite strands. Primers are typed in 5'-to-3' direction (aka left-to-right on leading strand). Appropriate primers will be: primer 4=GTG... and primer 5=GAA.... Note how those primers are always in ...


1

The article probably had a scrap of truth to it. Ageing is not plastic and longevity can be altered in a variety of ways. Although caloric restriction seems to affect longevity the most, there are also longevity genes from a range of cellular processes that have been identified in yeast and mice, indicating that ageing is a whole system process. But none of ...


0

I think you read about the telomerase: https://en.wikipedia.org/wiki/Telomerase The chromosomes while duplicating, they loose some of the DNA segments from their ends, from the telomer. This is believed to have a direct effect on senescence. The telomerase reproduces the end DNA strip of the chromosomes. This enzyme is found in active form in stem cells ...


1

In tissue culture and cell engineering fields, the word "immortal" is often used to express something else instead of human or animal life spun. When you take cells from human tissues and grow them in test tubes--although flasks or dishes are used in reality--, cells stop growing after long term culture. They say it is cellular senescence. Several genes ...


2

Practically, there is an obvious barrier to changes in chromosome number: haploid cells produced by diploids must contain exactly one copy of each chromosome (or chromosome section, or locus). Otherwise over- or under- expression of genes can lead to dosage problems. Across all of diploids some large groups show strong conservation of number of chromosomes ...


3

So, the very first map of the human genome was of a few pooled samples with a single nucleotide called at each position. This is basically okay, though, because humans are 99.9 (with possibly a few more 9s) % similar to one another. So you can get a lot of broadly-applicable information out of a single individual's DNA. Further genome-mapping efforts ...


7

It is already mentioned by canadianer that genome size differs between organisms. But what about complexity? First we should define what complexity is: complexity can be defined as number of different cell types that a multicellular organism can produce, with the same genome. Yes complexity does not correlate with genome size. However, it seems to correlate ...


25

Chart of C-values (the mass of DNA in a single haploid cell); there is no logical order to the groups: [source] Base pairs in haploid genome (some examples): Escherichia coli (bacteria): ~4.5 million Caenorhabditis elegans (nematode worm): ~100 million Humans (we all know what these are): ~3 billion Pinus taeda (coniferous tree): ~22 billion ...


2

I can show the facts here. Human: total length: about 3,000,000,000 coding genes: about 50,000 (included predicted ones) 3,000,000,000/50,000=60,000 Chromosome number: 23 Zebrafish: total length: about 1,400,000,000 coding genes: about 36,000 (included predicted ones) 1,400,000,000/36,000=38,889 Chromosome number: 25 Fruitfly: total length: ...


2

Most restriction enzymes have a 6bp restriction site (some have 8bp site also). So two restriction sites generally have to span 12bp. However some restriction sites can overlap. For example BamHI and SmaI: BamHI |______| GGATCCCGGG |______| SmaI In this case the total length has reduced to 10bp. However such combinations are not that common and ...


4

With a few exceptions among some bacteria, all species on the planet make protein from the same 21 amino acids, and the relative abundances of amino acids is very similar in proteins from plants, animals, fungi and even prokaryotes. See for example this article (available as PDF here). So protein from pretty much any food provides the same amino acids. The ...


1

Remember: A and B are genetic markers that might be linked to the disease gene. Neither A nor B are actually the hemophilia disease mutation (or gene), A or B are proxies, or substitutes for the mutation in the disease gene. Since it is an X-linked recessive, it is only the Mother's two X chromosomes that are candidates. You can completely ignore the ...


2

At the moment, the youngest diagnosed Huntington's case was 2 years of age. This paper appears to discuss not only this boy's onset, but also the diagnosis of symptoms in the early-onset disease. Here they research a link between age-of-onset and the length at which the repeats are. The thing is that these repeats won't just constantly get longer. There ...


1

From the comment section: We don't have to see the actual changes. It's like chemists who will mix compounds together and obtain a new molecule. They dont see the chemical reaction per se but can test the new molecule to make sure what they predicted would happen had happened. Finally we often use fluorescent proteins to track some of the modification ...


0

Your illustration is wrong. During second meiosis the sister chromosomes go to each their cell, not the same cell. This would correspond to switching the colors up in your illustration like this:


0

A genetic marker is, by empirical definition, something that you can unequivocally place on a genetic map. A genetic marker may be an allele of a known gene that confers either a dominant, or a recessive phenotype. Alternatively, a genetic marker could be either a restriction fragment length polymorphism--whose segregation can be detected by either a ...


1

Chromosomal aberrations have defined notations you can find here. The notation rule for multiple genetic abnormalities is to concatenate them. In the presence of an unbalanced translocation two abnormalities will be indicated as you have both a translocation and another event (e.g. deletion, duplication, ...). In your example, as no other ...


1

Genetic markers don't cut the DNA. They're simply regions of DNA sequence that happen to be variable between individuals (see my answer to your previous question). They might be measured using restriction enzymes (i.e. RFLP) to identify the exact difference, but it's not the marker that's cutting DNA. Furthermore, they don't necessarily cause disease. ...


1

This translocation is balanced: if it was not there was a specific sign for specific unbalanced event, for example "del" for deletion or "+" and "-" signs etc.


2

Let's consider all the options. X-linked recessive: I:2 is a carrier and II:5 is also a carrier, and I:1 is affected. Everyone who marries into this family(except for II:2, lucky guy. He better not have any sons though.) is a carrier for the same genetic disorder. While it does work, it's vastly less likely than the other options. Observe: II:4 is affected, ...


4

It's actually very simple. You misunderstood the term polymorph in this situation. A microsatellite is a sequence composed of a short repeated DNA motif. A polymorph satellite is then simply a microsatellite varying in length between individuals, i.e. composed of more or less repeats of the motif. The flanks of the microsatellite are the DNA sequences ...


3

I think you pretty much nailed the problem. If I understand correctly, you are just confused about the approximation that your textbook does, an approximation that is correct but not needed. Let me restate the solution to the problem first. Resolution of the problem As you said the frequency of sick people $\frac{1}{300} = 2pq + q^2$ in this case, where $q ...


2

As hello_there_andy (and also the Wikipedia page) has indicated, genetic markers are DNA sequences that can be used to distinguish individuals (can also be tissues, cells, etc.). Linkage of a phenotype with genetic markers is used to identify regions of the genome that are likely causative for that phenotype, as hello_there_andy says, but there is nothing ...


4

From a computer science perspective, there's nothing at all special about DNA. It's stored as a simple ASCII text file consisting of repetitions of 4-15 different letters. DNA, the molecule, is a long chain of nearly identical smaller molecules (nucleotides) joined together. The nucleotides differ only in which of four possible bases (A,C,T/U or G) they ...


-1

Genetic markers are sequences of DNA that tend to co-occur with some biological property, in a population. Examples E.g. Imagine you have 200 individuals in a population. 100 individuals have some sequence GGGCCCGGGCCC at some locus (position on the genome), and those 100 individuals have blue eyes. The remaining 100 individuals have AAATTTAAATTT, at the ...


1

According to Live Science, the temperatures are in the 120 to 300 degree-Fahrenheit range (48-148 degree-Celcius) when crude oil is forming. DNA in "dry" conditions completely degrades at temperatures above 190 degree-Celcius. Which means that there could be DNA in the oil itself if there are some surviving cells, however, outside the cells there are DNases ...



Top 50 recent answers are included