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5

Besides viral infections there are different pathways for cells to take up dsRNA. Inside the cells these dsRNA are processed by Dicer which processes these RNAs into small interfering RNA, which play an important role in the regulation of gene activity. These pathways have mostly been researched in Drosophila and C. elegans, I am indicating where evidence ...


5

CFTR is the gene which encodes the "Cystic fibrosis transmembrane conductance regulator", which is a membrane protein. Its function is to transport chloride and other negatively charged ion like thiocyanate ions from the inside of the cell to the outside (into the extra cellular space). This happens along a gradient, meaning the ions flow from the place of ...


4

First of all: We are not very different on the genetic level - the identity is somewhere around 99.6 to 99.9%. See here for details. If this wouldn't be like this, things like blood transfusions or organ transplants wouldn't work. To identify genes there are different routes. "In the old days" (meaning before the possibility of massive high throughput ...


4

In principle, Meiosis is only the process in which the haploid egg or sperm are generated. Have a look at this figure, which shows Meiosis I and II (from the Wikipedia): During Meiosis I homologous recombination between homologous chromosomes can happen, the chromosomes are then distributed normally among the daughter cells. In Meiosis II the cells split ...


4

Since only the male tail is equipped with various specialized sensory and copulatory structures that enable him to locate the vulva and successfully inseminate the hermaphrodite. Hermaphrodites can self-fertilize, but only males can cross-fertilize a hermaphrodite. sources: Wormbook: Male development C. elegans II (2nd edition): Sexual Dimorphism


4

Huntington's disease may become symptomatic starting from as low as 2 years old [1] and rarely after 55 years old [2] (yet there is evidence of onset at 65 years old [3] and even more according to newer studies). Figure: Copyright © 2004, The American Society for Experimental NeuroTherapeutics, Inc. Richard H. Myers. Huntington’s Disease Genetics. ...


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The CFTR gene is coding a protein called CFTR (Cystic fibrosis transmembrane conductance regulator). This protein is an ion channel, which allows passive transport of the Cl- ions through the cell membrane in both directions. This allows the cells to transport water due to the active transport of Na+ ions. The Cl- ions follow the Na+ ions with passive ...


3

During Endochondral ossification chondrocytes in the plate are rapidly dividing, newer daughter cells stack facing the epiphysis while the older cells are pushed towards the diaphysis. As the older chondrocytes degenerate, osteoblasts ossify the remains to form new bone. In puberty increasing levels of estrogen, in both females and males, leads to ...


3

In most tissues, close to 100% of DNA methylation occurs at CpG sites. This provides a straightforward mechanism for epigenetic inheritance. Since C and G are complementary, both strands have the CpG site at the same locus and methylation is either present on both strands or on neither. During replication, each daughter DNA molecule inherits a parent strand ...


3

Non-homologous end joining indeed induces errors in the affected sequence. But you have to keep in mind, that NHEJ is an emergency repair mechanism which involves a "repair or die" chance. If the chromosomal break is not repaired it is not unlikely that the cell will get into apoptosis, or, even worse, develops into a cancer cell. Introducing small errors is ...


2

NHEJ is indeed error prone. It is called "non-homologous" because it does not use a "homologous" template from another sequence-matching piece of DNA to guide the repair. Homologous repairs avoid causing mutations because the similar string of DNA acts as a template so that the cell knows what letters to put into the gap. When there's no template, there's ...


2

People can grow taller than their parents. Anecdotally: I'm 185 cm, my parents are 155 cm and 178 cm. Joakim Noah, an NBA basketball player is 211 cm, his dad was 193 cm and mother was 175 cm... how? Genetics and environment play a role in determining height. First of all, a more nutritious environment during development can lead to increased height, this ...


2

Yes it is quite possible, recall nature vs nurture. I myself am slightly taller than both of my parents by about a head. As long as you have sufficient nutrition it should be quite possible. And what you said about gene activation skipping generations is quite true- it can indeed happen, and if the gene responsible for height is not expressed in the parents ...


2

Eye color is sex-linked. So a green-eyed male has genotype G- (only one X chromosome) for eye color and BB for fur color. The female has genotype GgBb. For the offspring to be female, 1/2 probability, to have green eyes 1/1 probability (G is dominant and it will receive the G from the father), and for gray fur 1/2 (1/2 chance it will receive b from the ...


2

The male has a phenotype XGY BB, and the female, XGXg Bb. Thus the probability is 0.25.


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As someone who has dabbled in both biology and programming, I assume you are referring to the theoritical ability of functional programming to simulate organic behaviour from well defined input. From that point of view, our comprehension of the human cell behaviour is currently near stone age level. The astounding diversity of homeostatic and signaling ...


2

Wobble pairing is just a phenomenon and not a hard and fast rule. There are some justifications for why it should exist and that is why it is still called a hypothesis. And this statement is not true:"the base on the third position of the codon and that on the anticodon need not be complementary". The anticodon residue corresponding to the third residue of ...


1

Penetrance describes the frequency of a gene's expression: Penetrance refers to the proportion of people with a particular genetic change (such as a mutation in a specific gene) who exhibit signs and symptoms of a genetic disorder. (Genetics Home Reference nih.gov) More specifically: [P]enetrance is defined as the percentage of individuals with a ...


1

The Law of Independent Assortment: Alleles for different traits are distributed to sex cells (& offspring) independently of one another. This one is like written on the stone in my mind!


1

That's a valid explanation, but not definition. Mendel's law of independent assortments states that during the formation of gametes, the alleles for one trait segregate independently of the alleles of another trait.


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Most mutations to the DNA are heritable, but not all are inherited. Mutations occur in the DNA, DNA is then replicated and transmitted to offspring (cells or organisms). Generally all mutations are heritable because they can be inherited, but some aren't - either by random chance (drift) or deleterious fitness effects (selection). Any mutation which makes ...


1

I don't know what you really mean by "heritable changes to the genome". I think you will understand why this sentence makes no sense after reading what follows. I start with some background and then try to address directly what confuses you. Short introduction to the concept of heritability The concept of heritability may have two meanings. Heritability ...


1

First of all what do you have? This is a punnet square problem. It has 2 traits In this case, we have star eyes = st ---> lethal and x -linked dichaete = dia --> on a chromsome given on the information i gave you can probably draw some conclusions how to set it up assuming you did a punnet square.


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As Chris mentioned in his comment, 'printing' DNA from scratch (i.e. synthesizing a long strand de novo) is expensive and difficult. Unfortunately, the process of GMO creation is not as simple as assembling a beautiful DNA sequence on the computer, printing it, and then inserting it into a cell. Here's a related question about de novo sequencing. Plant ...


1

The chromosomes in your picture do have sister chromatids, they are just very close together. A chromosome needs to pass through replication before it can compact into the typical metaphase chromosome shape depicted above. When I prepare metaphase chromosomes, I usually see a mixture of chromosome sets where the chromatids are close together (like above) and ...


1

Grey hair is one of many age related traits. Other traits showing a positive correlation with age include Parkinson's, cancer, and Alzheimer's. There are two key theories as to why age-related disease & decline occurs. But the key message is just because something evolves, it doesn't mean it's advantageous. First of all is mutation accumulation (MA) ...



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