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Oranges and other fruits are generally not actively made seedless. Rather, seeds may fail to develop due to either lack of fertilization (pollination) or a natural tendency. The natural production of unfertilized and thus seedless fruit is called Parthenocarpy. To quote the Scientific American article (3) mentioned by Oreotrephes: Fruit development ...


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There is a section in the Human Molecular Genetics textbook about how such repeats do occur. Like the commentor said, it is likely a result of recombination. If there are repeats flanking a gene or an exon there can be paring between sister chromatids / chromosomes, which can result in the duplication. See Figure 9.7 here ...


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I'm going to speculate that exons that are not cleanly duplicated activate the cell death machinery. We see the clean exon duplications because they are able to survive.


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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)


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You are right that a person with an abnormal number of chromosomes will be unlikely to find an "equal" partner to mate with. This does not prevent a chromosome aberration from spreading though, and it is not necessary that the mutation is initially beneficial for it to spread. While it is true that many chromosomal aberrations may be detrimental and cause ...


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Unfortunately, that isn't a very well-written problem, but I think I can help. If we assume simple Mendelian genetics, this would be a monohybrid cross, as you're only examining one trait (flower color). You have a pure-breeding white flower and a pure-breeding red flower. These make up the P (parental) generation. Their offspring will be the F1 (first ...


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Assuming that red is homozygous dominant and white is homozygous recessive, this may help you: http://faculty.ucc.edu/biology-rohrer/Bio112_Files/mendel-punnett.pdf


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What do you call an acquired trait? A trait acquired during the lifetime of the individual through its relationship with the environment (especially culture and traditions in humans)? If you take any population of living organisms, the variance of quantitative trait in this population, also called phenotypic variance and denoted $V_P$ is the result of the ...


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@Remi.b's list is excellent, but it should also include Gillespie's Population Genetics: A Concise Guide.


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The way that your teacher describes is a way used by most of the introductory biology student. If you understand why that way is correct, it will seem more "concrete" to you. It is because there is less probability of having recombinants.


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I think the key work here is 'evolve'. Overall GC/AT ratios change by mutations, whose rate is constant. The probability that given a mutation event that one base will be substituted by another one has been modeled in several ways where the probabilities of different mutations may or may not be the same. Overall the GC content will tend to close to 50%. ...


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I haven't found a manual for this machine, but my guess is that you exceed the maximum current which the power supply can provide. This is something I have experienced myself for electrophoresis. Usually power supplies then switch into the constant current mode at the maximum current they can deliver, which I think is what happens here. If the voltage you ...


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To derive it, first use that $E[x(1-x)]= E[x-x^2]=E[x]-E[x^2]$ and that $E[x^2]=\text{Var}[x]+E[x]^2$ to rewrite the left-hand side: $$E\left[x_{t+1}(1-x_{t+1})\right] = E\left[x_{t+1}\right](1-E\left[x_{t+1}\right])-\text{Var}\left[x_{t+1}\right].$$ The equation for $p_{ij}$ is just saying that $2Nx_{t+1}$ is binomially distributed with $2N$ trials with ...


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The notation at this site resembles that in your question but preserves the $\frac{x_t}{2N}$ notation for probability of selecting an allele. $$E[\frac{x_{t+1}}{2N})(1 - \frac{x_{t+1}}{2N} )|x_t] = (\frac{x_{t}}{2N})(1 - \frac{x_{t}}{2N}) (1 - \frac{1}{2N}) $$ The expression $(\frac{x_{t}}{2N})(1 - \frac{x_{t}}{2N}) $ is the probability of heterozygosity ...


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A Biologist's guide to mathematical modeling in evolution and ecology (Otto) is a very good book that is presented for people that have highschool level in mathematics (It makes a good review in linear algebra for example). It is highly accessible and in the meantime it goes pretty far as it ends up talking about the application of diffusion equation in ...


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I got .59. In response to WYSIWYG: (Note: I'm using A and a for the two alleles. My copy of Bulmer uses B for the second, which makes a little more sense if the alleles are codominant.) a.) The AA x aa cross should be twice as common as the AA x AA and aa x aa crosses, just as HT is more common than HH or TT when we toss a pair of identical coins. In ...


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From the source that Amory cites : You know that the number of offspring is shown by Pascal's triangle, right? For two alleles you have 1 : 2 : 1 For three alleles 1 : 3 : 3 : 1 For four 1 : 4 : 6 : 4 : 1 etc. So, if 4 in 1000 are 12 and 36 cm tall, that means that every in 250 plants is tall like that. And on which level of ...


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The hairs you mention are also called "androgenic hairs", meaning their growth and pigmentation is influenced by androgens. These include pubic hair, the hairs on the breast and shoulders (almost exclusively for men) and the beard. It seems, that these hair bulbs have different sensibilities (number and expression of androgen receptors) so they react ...


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One of the alleles for each gene must come from the parent on the right hand side. That parent only has a and b alleles (is homozygous) - meiotic crossing over will not change this. So the offspring must inherit at least one a and one b. That should point you to the answer.


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I've heard it mentioned that gene dosage is implicated in this. Gene dosage is the number of the alleles present in the cell.


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With some exceptions (one being red blood cells), all cells in the body contain the complete genome of the individual. The expression of the genes however is, as mentioned in the comments, heavily regulated and different in various tissues. Early efforts at gene therapy have had mixed results, including some fatalities, and the field is still highly ...


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A Google search for "Huntingtons disease gene discovery" yielded this page at the Nature Education Scitable website. The following citations are provided regarding the molecular basis of HD: Huntingtin (HTT) was the first disease-associated gene to be molecularly mapped to a human chromosome (Gusella et al., 1983)2. Ten years later, scientists ...


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It was fascinating because Huntington himself described what we now call genetics before the field existed. Then to locate the gene scientists used essentially trial and error. They took enzymes that cut different parts of the DNA and looked at which of these were inherited. If it were inherited then there would be cuts made, otherwise not. Then they matched ...


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Yes a range of pain exists. This can be seen probably in your friends who all probably have a completely different threshold for pain. When doctors ask patients to rate their pain it's usually to establish a baseline so after treatment we can see if there's a decrease. The different thresholds have so many factors from general health to receptors to brain ...


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Question is: If an Ashkenazi(1/30) and(multiply) French-Canadian(1/30) .... Where 1/300 came from ? I duno, I may missing something - but may it be like that Parrent1(=1/30 * 1/2)*Parrent2(=1/30 * 1/2) = P(child with both mutations)


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BioGRID is an interaction database, and they catalogue interactions by (among other things) the class of experiment that discovered them. See http://wiki.thebiogrid.org/doku.php/experimental_systems#genetic_interactions Other than that, you should look at recent reviews and publications, but you will easily get lost unless you figure out some important ...


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The YAC contains a segment of chromosomal DNA. By using it as a probe they could screen the cDNA library to find cDNAs derived from that genomic region. This would be done by plaque or colony hybridisation. The cDNA clones thus identified represent the "candidate genes" . The last step is a little unclear. Clearly they are identifying cosmid clones that ...


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Hopefully this syllogism will answer your question. Given the following premises: In the absence of selection, fitness of individuals are at a theoretical maximum. If a theoretical maximum fitness is achieved then effective population size is maximum. If there is an allele that confers both increased and decreased fitness you have a genetic conflict (e.g. ...


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Min means minutes. Minutes are counted for interruption points since onset of DNA transfer in F-pili-mediated conjugation. The point "0" is not associated with ori, but is close to thr. The total chromosome size is 100 min (time taken for conjugation). See: Linkage Map of Escherichia coli K-12, Edition 10: The Traditional Map Recalibrated linkage map of ...


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Some bacteriophages adsorb on the pili. So the individuals carrying the F-element will be susceptible to these. F-plasmid encoded membrane protein PifA is responsible for the T7 resistance [See here]. The exact mechanism is not known If you see the list of references in the textbook chapter you will be able to trace the reference for a certain quoted fact ...


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Yellow would need the expression of red and green so that would mean the excision of the blue fluorophore. It would be one line with egfp and the other line with mKO2--- the order doesn't matter-- these represent chromosomes.


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The short answer is: Because of genetic drift. If a mutation does not influence the fitness in heterozygote individuals, then its frequency varies only through genetic drift while it reaches some high enough frequency. If by chance, the frequency of this new allele achieve a high enough level so that the homozygous for this allele given by $x^2$ where $x$ is ...


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In terms of inflammation, the purpose of pain is to force the organism to rest the area that is inflamed. Thus promoting healing. In terms of chronic pain, this is the same thing. However I think that if the pain will not cease regardless of protection of the affected area, and say if the underlying cause of the pain is ultimately fatal, then the pain is ...


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Opinion: the Jackson laboratory http://jaxmice.jax.org/ Is the industry leader in transgenic mouse production. Their list of mouse strains is almost a db in itself but currently no db exists that I'm aware of. I take it your looking for something similar to what's available for c elegans: http://www.celeganskoconsortium.omrf.org/


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It means that the direction in which the normal double-strand is wound up (which is also helical) and the direction on which the double helix itself is twited to reach the supercoils are opposite to each other. Have a look at this image from the Wikipedia, I think it makes this clearer: The first show a DNA ring with the normal helix-coiling. The second ...


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Question a The only possible genotype that brings a phenotype of 12 inches is: $AABBCC$. Similarly the only possible genotype that bring a phenotype of 6 inches is: $aabbcc$. In consequence the offsprings can only be: $AaBbCc$ which measure $2+1+2+1+2+1 = 9$ inches. Question b Now the question is: if we breed two $AaBbCc$ how many offsprings measure 11 ...


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This phenomena is known as achiasmy, where recombination is absent in one sex in a species. The Haldane Huxley rule states that in achiasmic species, the sex without recombination will always be the heterogametic sex (XY or ZW). This is basically the only consistent rule relating to recombination. There seem to be exceptions to every other theory and pattern ...



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