The study of genomes, the entire set of genes in an organism.

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How can I download a gene sequence from GenBank (NCBI)? [closed]

Could you tell me the steps to find and download a gene sequence from GeneBank? I would appreciate your help.
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777 views

What's the longest transcript known?

What's the longest functional transcript known? I'm wondering about RNA length post splicing, so not including introns.
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38 views

Genome-wide methylation analysis: sources of technical error?

We are doing a genome-wide analysis of methylation via bisulfite sequencing for an insect species. Previous experimental techniques have suggested the presence of methylation in this organism, ...
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38 views

Assembly reconciliation

We have some bacterial genomes that were assembled using Spades, they were sequenced with and IonTorrent PGM. There are many assemblers and they give different results. I was interested in a tool ...
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2k views

Why extract DNA from certain white blood cells instead of whole blood?

In my lab, human DNA is extracted from whole-blood samples. I don't actually do the extractions and I am not familiar with the specific protocol but I understand that platelets and red blood cells ...
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200 views

What if a Point Mutation is seen in only half the coverage for its location?

I've been looking at some sequenced exomes and found an interesting point mutation that causes a Proline-to-Leucine amino acid change in the protein. This seems like it could have a big impact on the ...
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301 views

How many different protein coding genes are in the Human Biome?

There are approximately 20k protein-coding genes found in the human genome. This number is presumably very small when considering all the genomes found in the diverse microbes associated with the ...
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883 views

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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50 views

What is the close and related genome used for in Gene models?

all I am a little bit confused about using the related genome or reference genome. When we have a reference genome, we can do alignment. Also we can do the assembly. Can you give some more reason ...
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In genome research, what is the problem in Mapping that may be caused by reads being too short?

In the following scenario: You were given short sequence reads of plant RNA obtained from a next-generation sequencing machine (fragments of 20–30 nucleotides in length). You attempt to map them back ...
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56 views

“Gold standard” for CNV detection methods?

Is there a generally accepted "gold standard" for testing the performance of CNV detection methods? I'm interested both in learning about existing datasets that may serve as gold standards for CNV ...
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100 views

Sequence alignment scoring

The following table is from Deonier's text Computational Gene Analysis at p. 152. This is an exercise in global sequence alignment and scoring of alternative sequences. The text proposed a solution ...
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468 views

How were the first primers made

I keep reading about how primers are useful in pcr -- they allow you to select a specific dna region. Similarly, in NGS or Sanger sequencing they give you a starting point. The primers I see are about ...
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70 views

Omics integration questions [closed]

Let's say that I have a population of Mus musculus in the lab. I divide it in a control group and a test group. The test group is constantly subjected to a stress (example: elevated UV radiation). ...
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109 views

Publicly available genotype data?

I am a statistician and I'd like to test my new method on biological data. For this I am looking for genotype data for a number of individuals. That is, I am looking for something like this: ...
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105 views

Databases for metabolic pathways of human disease

Which databases contain the metabolic pathway of human diseases? I have searched Metacyc and KEGG but didn't find the appropriate metabolic pathway.
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97 views

Systems Biology of triacylglycerol (TAG) synthesis in Jatropha

I need the genetic regulatory network of TAG synthesis (Kennedy pathway) of Jatropha plant?? Or is there any way to convert metabolic pathway into genetic regulatory network?
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178 views

How does the telomere repeat sequence vary in Eukaryotes?

Question: How does the telomeric repeating sequence vary in non-vertebrate Eukaryotes? If you know the repeating sequence of a given species I would appreciate hearing it. Background: Telomerase is ...
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71 views

Are recessive, deleterious alleles less common on the X chromosome than the autosomes in humans?

As there is a potential for them to be more readily purged in hemizygous males (and in cell lineages in females with the deleterious-allele-bearing chromosome activated), I would expect the frequency ...
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What is the genetic distance where linkage can be ignored?

I heard several times that two SNPs, that have at least 1'000 nucleotides between them, can be seen as 'unlinked' due to frequent recombination events. I also once saw a paper showing a graph "degree ...
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1k views

What is splice junction pairs?

Splicing is a modification of pre mRNA when all introns are removed and exons are joined. What is a splice junction pair? It is two exons which connected together?
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Need help distinguishing between a primary and secondary source

I am trying to figure out if the following article is a primary or secondary source. I'm leaning towards secondary but here are my cases for both. Primary: Published in a peer-reviewed ...
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124 views

Reference sequence for defining single nucleotide polymorphisms

Single nucleotide polymorphism (SNP) or genetic variation in general, by definition are relative to a reference sequence. When we talk about databases of SNP as in ("dbSNP—Database for Single ...
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103 views

Predicting host-pathogen gene interaction networks

Background What we have are: ~20 genome sequences for a host species that come with gene annotations Several sequenced genomes for parasite/pathogens of these hosts Question What are the ...
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Paired-end mapping exercise

Pair-end mapping (PEM) is a technique that allows to detect structural variants in DNA by obtaining paired-end reads and the comparison of their positions in a reference genome. Then among libraries ...
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what does sequences overlap indicate

what does it mean if different protein sequences overlap upon multiple alignment, are they the same, do they have a common ancestor, are they recombinants of each other and how does one go on to ...
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68 views

bioinformatics /genomics [closed]

i am looking for likely truncation sites to prove recombination in sequences. i have 4 sequences. i believe one to be the "real sequence" and the other 3 to be recombinants caused by cleavage possibly ...
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What about 23andMe's SNP test gives it such bad efficacy as a diagnostic tool?

The recent news about the FDA stopping the google backed 23andMe service selling any more kits got me thinking. I understand the company may have been selling it as a medical tool prematurely, but ...
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Regulation of the replication of mtDNA at embryonic level

While reading an article on mitochondrial inheritance I came across this link. The results state that mitochondrial DNA replication is regulated in different cells of an embryo at different levels. ...
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DNA and gene activation

As far as the genetic content of each cell is concerned I have read to my satisfaction that all cells of a person's body except the red blood cells (with no nucleus and so no genetic message) and the ...
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7k views

Difference between CDS and cDNA

What is the difference between Coding Sequences (CDS) and cDNA? Are Coding sequences the sequences that is transcribed to mRNA and cDNA in contrast DNA obtained by reverse polymerization of matured ...
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180 views

Why only heterogeneous SNVs for validation using genotyping arrays?

I am trying to validate the variants I found using whole genome sequencing . The standard practice, I have seen in the two publications below were to check for the number of heterozygous SNPs called ...
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178 views

What is the potential function of ultra-conserved elements in the genome?

If selection pressure results in conservation of DNA sequences, what is the most plausible explanation for the existence of ultra-conserved elements (refs here and here) given that there hasn't been ...
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607 views

Number of introns in a genome

Humans have approximately 21000 genes but they probably make more proteins than that. This has been explained by many mechanisms like alternative RNA splicing. My question is - If what we call as ...
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366 views

Variations in Genome Sizes

Why is there wide variation in genome size amongst groups of protists, insects, amphibians and plants, but less variation within groups of mammals and reptiles?
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204 views

Accuracy of a particular genetics test

I am a newbie in biology and I am simply trying to discover the field of genomics. Consider the question - Are genetic tests accurate? I don't believe they are as the genes may not provide the ...
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616 views

Amount of Heterozygosity

How many loci in the human genome are heterozygous? How about other species? EDIT: I was wondering, considering for example the whole world population, how many of the human genes actually have two ...
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Inheritance of Huntington's disease

People with Huntington's disease have HTT genes with more than 37 copies of CAG repeat. The risk of extra copies being generated is higher during sperm formation than during ovum formation. Why is it ...
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179 views

Results of a complete DNA sequencing - are they 100% reusable?

Is that correct that a complete DNA sequencing (the whole genome) need only to be done once (per person)? After that is done, it the complete genome can be stored and once the new genes (and their ...
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1answer
2k views

What does conditional analysis of a SNP in a GWA study entail?

I am familiar with the use of tag-SNPs in genome-wide association studies to identify gene loci involved in complex traits, but I keep seeing the term "conditional analysis" used without any ...
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347 views

How might gene clusters like the lac operon evolve?

The obvious answer for a gene cluster is gene duplication and mutation of one or both genes. But the genes in the lac operon seem not be so functionally/structurally similar (as compared to the Hox ...
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How are geneticists able to isolate gene functions?

As an example, this Scientific American article describes a known area in the dog genome that metabolizes carbohydrates. How is it that researchers are able to determine specific functions such as ...
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Combining gene expression data from two species

I currently have two sets of gene expression data. The first is a dataframe of genes identified by Annotation id CG numbers (for example "CG10005") in one column and a numerical variable of interest ...
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281 views

Can forensic DNA analysis be used to generate a visual approximation of a suspect?

In light of the current US supreme court case, I'm curious if enough information can be teased out of a DNA sample to get a "reasonable" approximation of the suspect (never mind the legality). I ...
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11k views

What is the difference between SOLiD, 454, and Illumina next-gen sequencing?

I've started teaching myself about next-generation sequencing in preparation for a new job, and I'm wondering what the main differences are between the 454, SOLiD, and Illumina/Solexa machines, in ...
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1answer
61 views

Is copy number variation dynamic?

Is there any evidence showing that copy number variation changes over time? I'm wanting to model interactions in expression level as a dynamic bayesian network, but an assumption my approach will need ...
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1k views

How to map the Gene name to its Gene Symbol?

I am learning in Gene data lately so I apologize for the silly questions in advance. I read a paper for a cancer on human which found some important genes. For example, the paper listed one of genes ...
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132 views

Comparative cost of RNA-seq vs sequencing full length cDNAs

I am in the process of assembling and annotating the genome of a non-model organism, using almost exclusively short read (paired-end Illumina) data. Throughput is one obvious benefit of these data ...
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92 views

Do antisense transcripts have different names than their sense strand transcripts?

I want to find which genes in the human genome can potentially be complementary to a transcript that could act as antisense transcript inhibtion? Are cis-NATs (naturally occuring anti-sense ...