36

Going through the possible answers (A) Rates tend to be very high in most populations. This is a very unclear statement. What does "high" mean? In humans, the average mutation rate per reproduction per nucleotide is of the order of $10^{-8}$ (Rahbari et al., 2016) (hence of the order of 10 - 100 mutations for the whole genome). Whether someone wants to ...


31

It is highly unlikely that there exist any protein that is made from completely identical nucleotide sequences across the entire human population. There will certainly be regions within a gene that are highly conserved, but there is little evolutionary pressure to conserve an entire gene's nucleotide sequence across the population. This is in part due to ...


19

Humans have many variants There is variation. The project I use to help understand this natural variation is gnomAD. Using VarMap and a slightly out of date gnomAD file, I counted 16007805 protein-coding variants across the human genome. This number will only go up over time. Indeed, the 1000 Genome project found that on average each person has between ...


9

What's the benefit of the average human body temperature? It's a balance between preventing infection and not requiring excessive food intake. It is has also been claimed that this is the temperature at which the most essential enzymes are most reactive, without becoming damaged by excess temperature. References: "Mammalian Endothermy Optimally Restricts ...


8

Are all genetic disorders inherited? Not all individuals with a genetic disorder inherited that disorder. Some genetic disorders are caused by spontaneous mutations. Is cancer a genetic disorder? Yes. The seminal paper by Hanahan and Weinberg, the Hallmarks of Cancer, is a good place to go to get a sense of what we understand cancer to be. This paper is ...


8

While @CalendarJ comments "Yep!" above, a quick search suggests that experimental hyperoxia typically only increases insect body sizes slightly. Everything below is from VandenBrooks et al. 2012 (of course there could be other sources that contradict this!) A few beetles have been reported to reach larger sizes when reared in hyperoxia, but most of the ...


7

Pseudoautosomal region in mammals On sexual chromosomes, we have a so-called PseudoAutosomal Region (PAR). The PAR is the region which still recombine with the Y chromosome (in males only) and is though to be important to allow separation of chromosomes during meiosis. Pseudoautosomal region and dosage compensation Because the PAR is diploid in males too, ...


7

Yes. Mutations can affect STOP codons and they do relatively commonly. These are important because they can lead to significant changes in the resulting peptide and are likely to affect protein functions or phenotype. For a point mutation (a single base substitution), there are several possible effects: silent mutation is a synonymous base substitution ...


7

Yes, it's still used. If you search Pubmed for "polycistronic", it offers you a chart showing the counts of the term by year (top right). Downloading the CSV and making a chart shows that it's never been a very common term, but it's still used. I suspect, but don't have time to check, that if you were to divide the use of the term by the number of ...


6

Genes are the "plans" for proteins in an organism; in turn, those proteins do all sorts of things, catalyzing chemical reactions and making up much of the structure of an organism. A hippo is much bigger than a mouse, but it isn't that much more complex: both are going to have the same sorts of organs like a heart, lungs, kidneys, liver, brain. If you look ...


6

Short answer Some genes on the X chromosome escape X-inactivation. Two copies of these genes are needed for normal development. These genes are also present on the Y chromosome. Hence, healthy males and females both have two copies of these genes. In Turner's, the SHOX gene seems to be one of the culprits, which is needed for normal skeletal development. ...


6

I think this analogy is not actually that bad, but you are making some incorrect conclusions from it especially regarding 'junk' DNA and which parts of a repository DNA holds (which shows the limits of analogy!). Think instead of the DNA of an organism as a single local copy of a particular commit. There is no remote to compare to and no list of historical ...


6

The thing that I think biologically interesting about this question has perhaps not been emphasized sufficiently in the answers so far which document that the term is still in use. This is why the term is still in use. As the poster states: I’ve seen “polycistronic” being applied to prokaryotic mRNA in old textbooks, but I’ve rarely stumbled upon this in ...


6

At the whole-gene level, there is likely no absolute conservation of any human protein-coding gene at the population level, though there might be complete conservation between individuals. Keep in mind that most human genes are on the order of tens of thousands of base pairs long, and only a portion of that length encodes functional motifs. There are, ...


5

The yellow/green color of seeds is on chromosome 1, but the color for for the pods is on chromosome 5. The smooth/wrinkly seed shape is on chromosome 7; however for the pods a similar contrast is governed by chromosome 4. The pea has 14 chromosomes (diploid). What you mentioned however are not all of the pea genes Mendel studies. He actually studied 7 ...


5

Mutations are one of multiple reasons for genetic variation, hence phenotypic variation. By definition, mutations are alterations of genetic code and unpredictable changes in nucleotide sequences {in nucleic acids(level)}. So yes, mutations are responsible for variation, but not all the time, and not all mutations actually result in variation. Silent ...


5

The science behind "being X % from a certain place" based on genetic analyses is... approximative at best. It relies on the assumption that some genetic traits are only found in certain (narrow) regions of the planet - which for most of them, is not really true. Additionally, did your test provide any confidence metric for this result? If not, it may mean ...


5

I will assume that by "identical twin", you refer to "clones". Individuals who share the same genetics but of course do not necessarily share the same womb. I won't pay much attention in detail epigenetic modification nor in the length of telomeres. While it has never been done for ethical reasons, we would probably be quite able to make a clone of a human ...


5

No single gene determines the height (a polygenic trait) of an individual. In fact, height is coded for by over 700 genes. Also, I'm caught quite off guard by your suggestion that height isn't linked to sex, which is obviously not true. One gene that is associated with a shorter height (to put it simply), ITM2A, is expressed more strongly in women and so ...


4

No (or a bit more scientifically: very very unlikely) There a couple of reasons why your idea would not work: Viruses are not alive, so you can't really kill them. The only ways to get rid of all airborne viruses at once would be to either: A) UV-sterilize the whole atmosphere (bad idea, good xkcd what-if question though) or B) fill the whole atmosphere ...


4

@AliceD's answer is excellent, but I thought it would be helpful to include an additional perspective. The issue here isn't that monosomy X shouldn't be a problem because the majority of one X chromosome is inactivated. It is that monosomy X isn't as big a problem as any other monosomy because the majority of one X chromosome is inactivated. Monosomies ...


4

The sense strand has the same sequence as the transcribed RNA. The antisense strand is read in the other direction. For a particular gene, the sense strand is the genetic code, the other strand is the complementary template used to transcribe the RNA from it. The resultant pre-mRNA molecule (before introns are spliced our) will be single-stranded in the 5’ ...


4

The main differences between RNA (ribonucleic acid) and DNA (deoxyribonucleic acid) is that DNA contains a hydrogen atom where RNA has a hyroxyl (-OH) group and RNA's uracil is substituted for DNA's thymine. The below image shows several deoxyribose molecules bound together, and off to the side, a ribose molecule. It is the OH group on the bottom right of ...


4

Edit: I would define genetic complexity as either genome size or number of genes. Either answer or information would work. Largest genome: Paris japonica, a rare plant. Its genome is 149,000,000,000 base pairs large. Approximately 50 times larger than the human genome, by base pair count. Higher number of genes in an organism: Daphnia pulex, a very common ...


4

Because in different cells different copies of the X chromosome might be inactivated. So, in (approximately) 50% of the cells you will have the X carrying the normal gene activated, and in the remaining 50% you will have the other. You might start reading something here, and then go in further detail to understand. A nice article is here


4

I can think of several possible terms for what you could mean (with my interpretation of what people in those fields do): Computational biology (the study of biological topics using computation) Bioinformatics (the study of biological topics using computation) Mathematical biology (the study of biological topics using mathematics) Sequence analysis (the ...


4

Of course. Just like any other type of mutation. If a mutation (incl. a chromosomal microdeletion) happens in the germ line, then the mutation can be passed on.


4

@iayork's answer provides a great approach to examining this question. I just want to corroborate it by using a slightly different approach. A Google Scholar search for "polycistronic" limited to results since 2015 provides >200 hits. Some examples include: Gordon, S.P., Tseng, E., Salamov, A., Zhang, J., Meng, X., Zhao, Z., Kang, D., Underwood, J., ...


4

No, it is not. As you said only 1-4% of non-subsaharan africans' genome is from Neanderthal and it is more or less the same sequences. The entire Neanderthal genome is not present in modern day humans, it is only a small set of sequences.


4

NMR spectroscopy is a technology that is used to identify molecules. So-called "NMR spectra catalogs" document the spectra of various known compounds. Acquiring these spectra requires purified samples, expensive equipment, and time. In addition to making next-generations of this technology into something that would be practical for realtime "smelling", you'd ...


Only top voted, non community-wiki answers of a minimum length are eligible