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10

This image from the Kahn Academy article 'Overview of transcription' might help: Essentially, the sense/coding strand of the DNA encodes the sequence that is transcribed. The RNA polymerase binds to the antisense/template strand, for which the code is indeed TAC, but when it then transcribes this strand it is again complemented, giving us the AUG that is ...


8

It depends on the regions of sequence homology between the two chromosomes. Crossing over occurs through pairing of homologous regions. If there's a substantial stretch of chromosome without a matching homologous region on its pair, that non-homologous region should loop out and not be involved in crossing over. Crossovers will occur only in paired ...


7

"Intergenic" is, well, an embarrassment, though it can be hard to avoid. Intergenic means, literally, between genes. Genes are, as you'd expect, genetically defined as regions of the chromosome with some genetic role. Between genes, we have, well, junk, spam, without meaning or significance, since otherwise, it would be a gene. In the 1990s ...


5

An intergenic region is just one of many types of non-coding sequence. Others include: promoters regulatory binding sites terminators introns aptamers ribosome entry sites There's a lot of stuff that's part of genes besides the protein coding sequence. A good way to get a picture of the sorts of things there are besides coding regions is to browse the ...


4

As a point of order, the existence of DNA was demonstrated first by Miescher long before these terms came up (around 1870). He called it "nuclein" but he pretty fully characterized it chemically. However, it was not until the 1944 Avery-Macleod-McCarty experiment published in 1944 that DNA was shown to be the hereditary material. Now a partial ...


4

Counting both strands is admirably correct, but most people will multiply the number of amino acids by three, not six. For example, nucleotide positions in a reference sequence will increase by 3 for each amino acid in the presumptive coding sequence. Besides, if you want to be that pedantic, you should say zero, since the DNA contains nucleotide residues, ...


4

A genomic library is generated for the purpose of encapsulating the full genetic component of an organism. You do this by fragmenting the genome with restriction enzyme that cuts at its recognition sequence. These fragments are then taken and cloned into a plasmid, so that they can then be sequenced inside the plasmid using common sequences that are found ...


3

It seems to me that "genic" is a perfectly good word. This paper uses "genic" directly as a contrast to "intergenic", so that seems like a reasonable precedent: ‘Noncoding DNA’ can be found both surrounding genes, and within genes (see schematic Figure 1). We will call the first type ‘intergenic’, and the second type ‘genic’, a ...


2

A significance test (i.e., p-value) allows us to reject the null hypothesis, but not to confirm it. In other words, when $p<0.05$ one can say that the conditions for HWE are not met, however $p>0.05$ does not mean that HWE holds - the conditions might still not be met, but we cannot prove it. Thus, by making statements such as All of the SNPs didn't ...


2

FASTA files are just text files, so you can open them up in your favorite text editor to see what they look like. The file you linked has a single entry. The first line begins with > and contains information about the sequence, delimited by | characters – the accession number, chain info, gene name, species, etc. Subsequent lines are just the protein ...


2

You have it mostly right, however, you are misunderstanding what has gone on here a little. The definition from Springer is correct - a targeted gene disruption is a direct replacement of the gene with a non-functional one. However, to do so you also need some method of detecting that your gene disruption worked and will persist. This is most commonly done ...


1

Here's a hint: you're right about 0.01 being the recombinant (crossed-over) double homozygous recessive offspring. I think you're forgetting that each offspring contains 2 gamete haplotypes, and so predicting the percent of offspring with a given genotype involves multiplying the frequencies of the individual gametes that produce that offspring. To calculate ...


1

Exactly . Paralogs and orthologs , both go under natural selection. But harmful mutations tend to have a less fatal effect if they happen to paralogs as there would be a backup for the malfunctioning protein. In paralogs, if a bad mutation happens to a protein, the paralogous protein will compensate and help the organism maintain its function but in ...


1

$\gamma$-irradiation produces single- and double-strand DNA breaks, depending on the dosage, and activates DNA damage repair pathways like p53. During this time, the cell cycle arrests and most if not all mRNA production ceases. For sub-lethal doses of $\gamma$ rays, I would expect to see newly-produced mRNA levels drop off fairly quickly with time following ...


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