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13

From a certain point of view you could argue that our bodies have an inherently limited lifespan; Telomeres are extensions to the end of chromosomes that prevent damage or loss of genetic information during cell division. Telomeres are not replaced (in normal cells), which gives rise to a replicative lifespan; the number of times a cell can divide before ...


11

tl;dr: In the Human Genome Project, they used the DNA of four people (though one male provided >70% of DNA. The Celera genome was compiled from five people. In the [...] Human Genome Project (HGP), [...] scientists used white blood cells from the blood of two male and two female donors (randomly selected from 20 of each) -- each donor yielding a ...


10

Inbreeding depression, "the reduced survival and fertility of offspring of related individuals" (quoting the linked article), is a well-known and well-understood biological effect. It does, indeed, affect humans. The problem is that recessive mutations become more likely to affect the survival of the offspring of relatives. Imagine that you have a mutation ...


9

In 2004 Bejerano et al. identified "481 segments longer than 200 base pairs (bp) that are absolutely conserved (100% identity with no insertions or deletions) between orthologous regions of the human, rat, and mouse genomes". These were found to be mostly in/around genes related to RNA processing, which is perhaps unsurprising given that it is such a ...


9

Alu elements are a type of transposable element. They possess the means for their own duplication and movement. Alu is a SINE-like element that is transcribed by RNA Pol III, and so a single DNA copy can make multiple RNA copies, each capable of inserting into DNA, so it's no wonder they have a very high copy number. Here is a picture of one means of ...


8

A human genome sequence can uncover large deletions and insertions in the genome and would give the genotypes of both common and private (rare to very rare) small polymorphisms (e.g. SNPs) and SSRs (simple sequence repeats). From this information, one can learn about some curiosity traits (say, sensing asparagus metabolites in the urine, slow or fast twitch ...


8

Because of the retrotransposon ability of Alu and other interspersed elements, insertion into parts of the genome can contribute to genetic diversity among the population. This can be analogous to random point mutations accumulated throughout a lifetime. Some of these mutations can be beneficial and increase the overall fitness of the organism. However, ...


8

Concerning the first question, it is very well possible to alter human genetics by injecting a highly radio-active substance that will eventually cause mutations almost all cells. The lifespan will be dramatically reduced, however and the condition is known as "radiation sickness"(link to Wikipedia). But the person probably means so-called "directed ...


8

The human genome contains less than 416 base pairs, so, even after including a factor of 2 for the two strands and another to allow for some genetic variation, there must certainly exist some 17-base string not found in either strand of the genome. Now, 417 bits is two gigabytes, which fits easily within the memory of a typical desktop computer these days, ...


7

First of all it is important to note that, within certain limits, human DNA is not much different than, say, a mouse DNA: it has the same structure, it is constituted by the same bases etc etc. Therefore it is teorethically possible (leaving aside ethical issues, of course) to selectively modify it as you would do for a mouse. There are, however, some ...


7

No, your approach will not work, you are taking a very simplistic view of an extremely complex system. Some of the problems you are ignoring are: Genes (eukaryotic genes anyway) are spliced to produce mRNA, a process that removes introns and leaves only the exons. If you just translate the entire chromosome file you will get noise. Splicing also changes ...


6

The processes that control the germline of metazoans (multicellular animals) are highly regulated compared to single cell bacteria and eukaryotes as well as plants. At this point there are no clear stories of gene transfer into a complex animal, though there are some for plants: "animals and fungi seem to be largely unaffected, with a few exceptions, ...


6

A major limiting factor in such an exercise is the complexity of the biological process under question (eye colour etc.,) and thus, our nascent understanding of these. What I mean is that there is not a single gene that determines a given characteristic, rather it is the complex interaction of a set of genes in different conditions responding to ...


6

You bring up a good point. "Coding" is a term that obviously carries some historical baggage that is gradually becoming less and less relevant. "Coding DNA" has typically been used to refer to DNA that encodes one or more functional protein products, which are constructed from an mRNA intermediate. As we've been learning over the last several years (and as ...


5

These are sequencing gels (in the cases here even radioactive ones) - they are run a lot longer than ordinary agarose gels and they are made from polyacrylamide. Im my experience, the most likely cause for skewing of lanes (not only bands) are samples, which still contain too much salts from the PCR reactions. This can also happen to only a few bands as seen ...


4

How is the genome sequence useful right now? There are several tests out there that rely on identifying single mutations that will lead to diseases, or that are associated with bad response to medication. Having the entire genome sequenced allows identifying all of them at once, and is cheaper than doing these diagnostic tests one by one. Thus, sequencing ...


4

A single run of sequencing won't cover the entire genome, in most cases. That's why they do multiple rounds in order to increase horizontal (covering more regions of genome) and vertical (a.k.a depth; more reads per locus so that you can be more confident) coverage. Edit by dd3: In the cases where "a new gene is discovered", i.e. genome reannotation, it is ...


4

The long and short of it is that genetic variation is actually not very predictive in comparison to "environmental" effects such as lifestyle. Only a quarter of the variation in lifespan between twins is attributable to inherited factors (including genetics and epigenetics) [1] - the rest is environmental, from lifestyle to air quality. Most genetic ...


4

This actually wouldn't be too difficult to find. A common algorithm in genome assembly first takes stretches of DNA and finds all the substrings of length k that are present. (These are known as k-mers and the algorithm then builds the assembly based on how k-mers overlap.) So, given a genome(s) it's not that difficult to find all the k-mers of a certain ...


3

You are correct in thinking that any sequence of bases corresponds, via the genetic code, to a sequence of amino acids. However not all stretches of DNA are actually transcribed into mRNA for translation into proteins. For this to happen the stretch of DNA requires (DNA-encoded) elements to promote and regulate the transcription and translation processes, ...


2

Human endogenous retroviruses (HERVs) have been an interesting (and expanding) topic of research in evolutionary biology and medicine. A retrovirus has an RNA genome in the virus particle, and integrates with the host cell's DNA upon infection to hijack the transcription/translation machinery and produce copies of itself. For this reason, it is not possible ...


2

SRY translocation to the X chromosome clinically exists and characterizes the De La Chapelle Syndrome. The phenotype associated to this syndrome demonstrates the necessity of other components on the Y chromosome to develop full masculine characteristics.


2

The devil is in the details, and therefore we cannot just state that we have understood X% of the DNA. We know e.g. that 2% of the human DNA encode proteins. And for a good number of proteins we know what they do. So you might know that a particular codon AGT encodes a serine residue in a protein, which could have a catalytic activity. Or it has a structural ...


2

You may consider consulting the H2DB database. The database is quite new, so the number of heritability estimates is not very high at the moment (currently 225 estimates for human, 838 estimates in total), but it's a start. The database is described in a paper by Kaminuma et al.(2)


2

I would recommend using Biomart from Ensembl. This is basically a Swiss Army Knife for converting gene names into various IDs, getting corresponding locations on the chromosomes and so on. You can upload a list of gene names and convert them into the corresponding gene IDs of other species and the convert these IDs back to gene names. If you haven't used ...


2

The GOLD database (Genomes Online DB) contains data on the sequencing status, and also some stats (number of chromosomes, genome size) -- but this extra data is not available for all species.


2

If you want an actual number, well, it depends (of course). First off, what is your definition of loci? That term is broad, and can be construed to mean everything from large, megabase-length genes to every individual base. That being said, it turns out there are some serious runs of homozygosity (ROH, meaning long regions of the genome that are ...


2

There are several lists on Wikipedia, for example for plants, bacteria and eucaryotes.


2

For the classic Sanger sequencing you need quite large amounts of DNA to be able to run the sequence reaction. This is a problem when you want to sequence whole genome since the DNA needs to be amplified then, which for some sequences can cause problems, introduce errors or cause bias. Single molecule sequencing is a huge step forward here, since only one ...


2

If you are looking for variations in a gene, there are a few databases you an consult. You can of course use the usual genome browsers, search for your gene and then select the variations listed. For ADRB2 this looks like this on Ensembl. If you plan to retrieve and compare data from different genomes/genes, I really recommend learning how to use Biomart, ...



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