Tag Info

New answers tagged

3

Saliva buffer usualy provides stability at RT for month or even years. Genotyping companies like 23&me use collection kits like Norgen's (https://norgenbiotek.com/product/saliva-dna-collection-preservation-and-isolation-kit) which allows to store the sample up to 5 years. So my advice would be: get the spitting vial at your place, send it as regular ...


1

Human cells are irradiated with X rays (to fragment the DNA) and then fused with rodent cells. This is useful for mapping because closely linked markers are more likely to appear in the same hybrid: there is a lower probability of radiation induced breakage between the markers because they are close together.


2

This is a combination of multiple regulatory systems. Most genes are not regulated by a single factor, but by many. Moreover in eukaryotic organisms there is also epigenetic, which "inactivates" permanently certain areas of the genome by compacting these zones forming heterochromatin. Moreover, even when we are interested in a single function a TF might ...


0

So you have various cell lines with different mutation rates (at least in each gene). The best way to see if there is a high mutation frequency (HMF) is to set up a control that you know does not have a HMF. To have a statistical meaningful threshold I would have at least 3 or 4 control lines, at best 10. The amount of mutations that you find in each gene ...


0

The amount of recombination events does not have anything to do with homologous recombination repair and meiotic homologous recombination, protein-wise. Homologous recombination repair is a "very safe" repair system, especially compared to the alternative option, Non Homologous End Joining, which is really prone to indels. On the other hand, meiotic ...


4

Those are the break points of the inversion. So chromosome 4 was cut at p13 and q22 and the fragment was reinserted in the reverse direction, giving a pericentric inversion.


3

Remi.b talked at great length in his answer about copy-number variation and the generation of new genes. However, I don't think he quite answered what I think is a pretty basic question: How many copies of any particular gene are there in (a human) genome? The answer to that question is also simple: two - one on the chromosome from the mother, and one ...


1

Unfortunately, it does depend on sequencing techniques. For example, in Illumina sequencing, each sequence fragment is amplified (in order to get a stronger signal) and forms a cluster on the microarray. Each cluster is sequenced by cycles of: Adding fluorescent terminator nucleotides. These nucleotides are modified to contain an inhibiting/terminating ...


3

Cell cycle Talking about physical copies of gene, we would indeed have at least 1 copy during the haploid phase, 2 copies during the diploid phase and 4 copies during the mitosis (and during the first phase of the meiosis). Of course, species having mitosis during the haploid phase would have 2 copies of the gene during the mitosis. I am not talking about ...


1

Are there mutations that would make one longer than the other? If they're not exactly the same, what's the range in length variation? As pointed out in the other answers, there can be mutations that change the length of the DNA between individuals and even single cells of the same tissue. There are different processes that can change the genome length. The ...


10

Welcome to Biology.SE. if I take an X-chromosome from two random humans would I count exactly 155,270,560 base pairs in both cases No, you would probably not find the exact same number of base pairs because mutations do no only change one nucleotide to another (what we call a substitution) but sometimes add or delete few (or sometimes many) ...


6

Humans generally have similar nucleotide counts, but they are not often going to be exactly the same. What allows for this variation is multiply determined, but here are some ideas. The neutralist hypothesis states that most genetic change is not subject to selection [1], and this is especially evident in humans where there is a lot of junk DNA outside of ...



Top 50 recent answers are included