Questions tagged [recombination]

The process of breaking and recombining strands of DNA.

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1answer
16 views

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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101 views

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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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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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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100 views

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 ...
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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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Recombination between organelles?

In plants, organelles DNA inside chloroplasts and mitochondrias can undergo recombination, intra- or inter-molecular. In a single cell, there are numerous chloroplasts/mitochondria. Can we imagine ...
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2answers
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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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64 views

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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1answer
25 views

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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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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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 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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1answer
241 views

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 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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Why doesn't recombination occur in male Drosophila?

"Males do not show meiotic recombination, facilitating genetic studies." For a while I have known that this phenomenon occurs, this quote comes from the Wikipedia page on Drosophila melanogaster, and ...
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1answer
183 views

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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What's a non-allelic gene?

Non-allelic or non-alletic I stumbled across the term in my Human Genetics textbook. It didn't explain it there, and a quick google search only showed scientific papers that refer to 'recombinations ...
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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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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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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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2answers
231 views

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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1answer
156 views

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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4answers
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Mitochondrial DNA and recombination

Firstly I could do with a brief description of mitochondrial DNA. How does the structure of DNA in mitochondria compare to animal DNA (for the sake of simplicity let's say human - some animals might ...
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1answer
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recombination frequency problem

Three loci C, D and E are located on the same chromosome in this order. We found that the frequency of recombinants between C and D is 10% and that between D and E it is 20%. Assuming that ...
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Possible Genotypes — Linked Genes

Please consider the following question: Genes A and B are located on the same chromosome. If two individuals with the genotype shown below are crossed, which genotype could be formed? Let / ...
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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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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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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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Calculating the recombination factor of four point genetic cross?

So, I'm trying to work out the recombination factor (RF) from this set of data: Which shows the 16 phenotypes of progeny of a cross of Saccharomyces cerevisiae yeast. I know how to go about a three ...
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1answer
334 views

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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1answer
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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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Mitotic crossover happens in G1?

I was reading this article in wikipedia and came across this : It has been suggested that recombination takes place during G1, when the DNA is in its 2-strand phase, and replicated during DNA ...
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1answer
374 views

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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1answer
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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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Why does the stability of YAC increase with size?

From Lehninger Principles of Biochemistry : The stability of YAC increases with size (up to a limit). Those with inserts of less than 100000 are gradually lost during mitosis. Why does this ...
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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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Hill-Roberston effects and effective population size

From this article, first page, middle of the second column: Even if harmful alleles do not become fixed, they can still reduce the efficacy of selection on neighbouring loci through a process ...
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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 ...