Biology

Questions tagged [recombination]

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The process of breaking and recombining strands of DNA.

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How do we select the location for insertion of recombinant DNA?

Transgenic organisms are made by cutting the DNA with restriction enzymes, inserting a foreign piece of DNA and pasting it with DNA Ligase. But how do we tell the restriction enzymes where to cut? ...
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How many of the four meiotic daughter chromosomes of a homologous pair can be recombinant via crossover?

In graphics I've seen, crossing over occurs between the "inner" two chromatids in a side-by-side arrangement of two duplicated chromosomes: This suggests that only two of the four meiotic daughter ...
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Why is Homologous Recombination (HR) more frequent at long sequence repeats?

I'm studying plasmids in bacteria (E. coli), and trying to understand the well-cited phenomenon that recombination frequency increases with longer repetitive sequences. I think this also applies to ...
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How quickly does recombination shuffle chromosomes?

For each pair of homologous chromosomes, one was inherited from the father and one from the mother. If there were no recombination in meiosis, one could then say that one of the chromosomes was ...
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Meiotic recombination hotspots

Im trying to find a proper and general file with chromosomal coordinates for meiotic recombination hotspots. I know that ucsc hgtables, has a table with recombination regions and their recombination ...
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Are highly-polyploid organisms more resistant to ionising-radiation-induced DNA damage?

Homologous recombination, although most famous for its use to mix together maternal and paternal alleles during meiosis, is most commonly used as a DNA-repair mechanism, allowing cells to repair ...
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Help with gene linkage and mapping!

Here's an interesting question I've been trying to figure out: My annotations are in red. So far, I've figured out: We know 630 colonies survived when plated with ACD antibiotics...meaning they ...
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chromosome 19 and recombination

Im doing a project with structural variation created by recombination within the human genome during spermatogenesis, where im especially examining intrachromatid homolog recombination. I find that ...
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Insertional inactivation using pBR322

I have questions regarding "selection using insertional inactivation". In a typical DNA recombination experiment using plasmid pBR322 where a new gene in inserted in the place of tet gene, it is ...
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Why do genetic testing companies (FTDNA,AncestryDNA,23andme) express DNA shared in centimorgans (cM) instead of in number of base pairs or in percent?

Expressing DNA shared in number of base pairs or in percent of total genome would be so much simpler and easier to understand for the customers. .
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How did the molecular machinery for recombination originate?

I'm wondering about the origins of genetic recombination. During crossover new chromosomes are created. They have different allele combinations from the original two chromosomes. This process allows ...
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How is the right amount of nucleotides synthesised during homologous recombination?

I'm reading about homologous recombination in the context of double-strand break repair. It seems like the trick is that around the break, homologous recombination uses a template duplex to generate ...
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Cis and trans linkage

Question: Two dominant non-allelic genes are 50map units apart, the linkage is: (A) Cis type (B) Trans Type (C) Complete (D) Absent/Incomplete My take: After a lot of searching on the net I found ...
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Difference between crossover rate and recombination rate?

I am not a biology student and therefore, need clarification if crossover rate and recombination rate are the same thing. So if the text says 'recombination rate per base pair per generation' or '...
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How is a specific fragment isolated for PCR amplification?

For background I am interested in studying engineering applications of a specific protein, which is not commercially available. My end goal is to express the gene for the protein in bacterial cells, ...
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Join a linear plasmid just using a primer (without ligase enzyme)

Can I use just a primer and PCR to join the cutted plasmid like this ? without using any further enzyme like ligase. After the linear dsDNA plasmid annealed into 2 ssDNA, primer will bind to middle. ...
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Lambda red recombination without electroporation

All protocols that I found about Lambda red recombination are using Electroporation as a method to introduce (inject) the homologous DNA (usually a PCR products or a linear dsDNA) to the E.coli cell. ...
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Are there chromosomes that we inherit that are not recombinated? [closed]

We do have chromosomes that recombinated ,but aren't there pure chromosomes that are not recombinated that people would have?
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How would one go about isolating a specific mRNA out of a pool of others? [closed]

I'm writing an essay about DNA recombinant techniques where the question asks to outline all the steps to arrive at having a colony of bacteria expressing a gene of interest.The question makes you ...
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DNA strand displacement and Branch migration- the same or different or interrelated?

So, recently I have begun studying DNA strand displacement and then I come across the term 'branch migration' (p.s. I am not a biology major student). What I understand is that branch migration is ...
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How would homologous recombination and mutations affect speciation?

I'm wondering how homologous recombination and mutations can affect how speciation can occur from one species (so that 2 will be created). I'm doing research and I found that different mutations and ...
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How do biologists determine the parents of a child

I am not well-versed in biology so this question might be wrong. As far as I understand meiosis, two germ line cells with 23 chromosomes each (one cell from the father and another from the mother) ...
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Why does the insulin taken from pig when injected into humans causes allergy but not the insulin taken from bacteria?

At earlier times, insulin was injected to human patients that were taken from pigs and horses. But that caused allergy it seems. But why is the insulin produced by the recombinant bacteria not ...
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How exactly are genes swapped during the process of recombination?

I am studying recombination in Meiosis and the idea of crossing over doesn't make sense. My understanding is that 46 chromosomes in our germ-cell (23 from mom + 23 from dad) line up next to each other ...
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Question about genetic recombination

I am having some difficulty understanding a few things about genetic recombination, in part because of confusion from different diagrams in books. First of all, I wanted to verify whether I have ...
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Need clarification on Coalescent with Recombination

I've been reading about recombination with coalescent. The link to that file is as follows: http://www.stats.ox.ac.uk/__data/assets/pdf_file/0008/4688/Reading_for_Recombination.pdf I get the part ...
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Questions in Regards to Isolating Promotor Region for Recombinant DNA Techniques

For a while now I have been trying to isolate the promotor region of this Protein. Using sticky end PCR, I need to isolate this promotor region so it has paticular sticky ends for the purpose of ...
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How is randomness of the branch migration process ensured?

Branch migration (part of genetic recombination) is a random process. It looks like Ruv-ABC proteins are mainly responsible for this process, but how is randomness ensured? After all, it can only be a ...
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Restriction enzyme digestion

A circular plasmid of 10,000 base pairs (bp) is digested with two restriction enzymes, A and B. This produces a 3000 bp and a 2000 bp bands when visualized on an agarose gel. When digested with one ...
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Heteroduplex and Products of cleavage of Holliday Junction (Resolution) [duplicate]

In homologous recombination (Holliday model), the last process i.e resolution can occur in two ways (horizontl and vertical cuts) leading to formation of either "splice" or crossover products or "...
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Why does meiotic recombination disrupt the independent assortment of genes on the same chromosome?

There are many sources that say that genes that are "linked" by being on the same chromosome assort with each other -- that when an allele is passed on that the gamete containing said allele will also ...
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Data on Recombination rate and Gene Positions in Humans

I am looking for estimates of per base pair recombination rate in humans and indication on gene positions. The goal is to be a able to plot recombination rate in the y-axis and position (in bp) along ...
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What is the difference between conditional and inducible activation?

In the modern genetically modified animal models, there are not only constitutive mutations which start producing proteins already in the embryo, but also mutations which can be turned on later. I've ...
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meaning of “usually greater than 200 base pairs”

From "Risks from GMOs due to Horizontal Gene Transfer", by Paul Keese: Homologous recombination. All cellular organisms have molecular functions dedicated to recognizing and recombining DNA ...
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Recombination fraction( frequency) in Homozygotes

I have a question about the recombination frequency I hope you have time to answer. Background: If we look at homozygous individual A/A B/B which has been formed from the gametes AB and AB, this ...
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Genetic linkage greater than 50 centimorgans

Classically, the linkage between two loci can be measured in centimorgans (cM), which represents the percent chance that these two loci will recombine an odd number of times (generating a recombinant ...
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How do I find the sequence of the phage BxB1 gene?

Specifically, I'm trying to find the sequence of BxB1 and its att sites. I have success finding the att site sequences, but I'm having a bit more of an issue with finding the sequence of the actual ...
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1answer
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Which process is right to describe V(D)J recombination? RAG-1 and RSS recurring process

I'm studying V(D)J recombination. I think I have two incompatible books about explantaion of the process. Which is right? In Molecular Biology of the Cell 5th Ed., firstly RAG (-1?) combines to RSSs ...
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Understanding recombination scoring in family pedigrees

I am having some problems understanding recombination, and I am not sure what element I am missing here. This figure is an example from my text book. The pedigree belongs to a family with an autosomal ...
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How long the homologous arms of the “repair” sequence must be to do homologous recombination? [duplicate]

I am trying to figure out the details of the homolougous recombination in order to be able to insert a certain piece of DNA in the host genome after double strand break.. Does anybody know how long ...
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What mechanisms exist for the excision of specific sequences from DNA?

I already know about recombinases (specifically excisionases), but was wondering if there were other mechanisms present.
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Is recombination suppressed in the males of all Drosophila species? Any other species?

Following up from this question, I am wondering if the phenomenon of genome-wide suppressed male recombination is limited to Drosophila melanogaster or is common to all Drosophila? The answer to the ...
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Why asexual reproduction?

When I took a course on genetics and evolution, I learned that recombination and sexual reproduction is advantageous compared to asexual reproduction. Sexual reproduction allows more combinations of ...
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Effect of recombination on the rate of loss of genetic variation

Following up from this question: Does recombination increase the additive genetic variance for fitness? (I'm thinking about the evolution of additive genetic variance and differences between the sex ...
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Recombination frequency as a function of genomic location in E coli?

Are there any databases or papers that give recombination frequency as a function of position in the E coli genome?
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Why are recombination rates increasing in mammals?

I have recently become fascinated with an awesome topic in biology and evolution that I feel is rarely covered in biology courses. That is, rates of meiotic recombination, or the the amount that an ...
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A Genetic linkage problem [closed]

I have recently switched from electronics to computational biology. So having some hard time with my homeworks. Can someone guide me on this problem? Consider 6 genes A, B, C, D, E, F, G. Some ...
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How many recombination events are there per generation in humans?

I'm looking for a reference that tells me how many recombenation events occur in humans from one generation to the next. Assuming that the human genome is a 3.3 GigaBases long DNA sequence, how many ...
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Breaking a gene during recombination

I just started reading about recombination frequencies of genes and related stuff, and can't find an answer to this (possibly naive) question. Can recombination possibly "kill off" a gene ? To be ...

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