Between your visuals and the way you simplify your teachings, it makes it very simple and easy to understand concepts that I was previously struggling to understand, Thank you.
I just love these videos u make!!! Everything makes sense. It shows the reasons behind what cells do and why they do it. This has being so helpful in my courses! Thank you so much!
There's one thing I am confused about. So if the histones are wrapped around our genes, and say you become a smoker (but no one in your family tree extending hundreds of years smoked) and the chemical tag is added to the histones to make that gene become 'expressed', does that mean that the 'smoker gene' is predetermined? In other words, will I have a 'smoking gene' by default that is turned off, but will only be turned on if I smoke?
I have a question that I'm hoping someone can answer for me: If you have a gene for, say, Schizophrenia in your body but that gene is dormant (and it would have been dormant in your kid’s body), and you do a certain drug (like cocaine) that expresses that gene, does your child have a higher chance of expressing that gene because of the drugs you did? Basically, does doing drugs (which falls under the "nurture" part of epigenetics) change the genes that your children will EXPRESS, rather than simply have? Hope that made sense haha
How do cells make sure that only the right bits are switched on or off? - in both systems. Also, how do you inherit such switches from your parents? Last time I heard this, you could have a transfer of some such traits by your mother easily but father-side epigenetic traits don't transfer. Is this incorrect?
Cells know where they are in the embryo because of protein gradients. The fertilized egg has proteins that are highest in concentration at one end of the cell and lowest at the other end. When the cell divides, one of the daughters will have less of the protein (the one from the end of the egg at the low concentration side of the gradient) and the other will have more of the protein. These proteins are usually transcription factors, that will turn on new gradients.
I didn't get how can you pass epigenetic modification you chromosome to kids. Especially on the context of diabetes. Shouldn't spermato and oogenesis be separated from all the epigenetic modifications?
Can someone explain further how epigenetics are inherited? There seems to be no histone acetylation or methylation of the first cells of an embryo because they have no expression of any particular genes yet. How is something like diabetes passed on if gametes, sex cells, and stem cells are undifferentiated and basically a blank slate?
Research has shown that sometimes epigenomes are imprinted within the gametes, yes it is often for the epigenomes to be erased while the gamete is created, but there are some imprints that get passed on. Go search Ted ed
Hey Mr Anderson, Thanks a Lot for the Awesome videos... very simple and precise.. The videos are nicely illustrated and clear.. Great work..!!!! Time saving and easy to understand.. Keep up the good work..!!!! :)
I'm not in a class or anything. I'm just trying to learn more about Epigenetics because I think it's a fascinating subject. Your video is very helpful and easy to follow. Thanks.
I don't know why but I find it very pretentious/egocentric when someone introduces themselves as being "MR. etc" - That being said, it looks like you've fixed that in your new videos. Cheers!:)
Post Traumatic Slave Syndrome" (aka transmittance of trans-generational trauma) Dr. Joy Degruy But,...Uh-Oh, we don't want to open Pandora's box...do we??? smh
What about histone methylation? How does that affect DNA packaging and why does it sometimes lead to repressed transcription and sometimes to activated transcription?
I get it, I do, but how does the inheriting process work? If I'm really good at dancing and skateboarding and balancing and things like that, how would my sperm know that.
just another layer of complexity that i must believe on faith happened by random, chance, undirected mutations if people are to accept my opinions as creditable... God's best
Methyl groups are hydrophobic, so don't interact very well with water. As the environment of a cell is very aqueous (watery), addition of methyl groups to the DNA induces tighter wrapping of the DNA around the histone proteins. If you like, the methyl groups on the DNA "hide" from the external environment. tighter packaging of the DNA thus decreases the chances of successful transcription... :)
Thank you soooo much for all the video you posted. You have helped me and my classmates in ways you may not understand. Please continue to post these video....Can you do one on inheritance patterns,the Molecule of Heredity and the Gene Expression and Regulation?
These proteins don't last long though so the positional info they give is temporary. The proteins direct epigenetic mechanisms to turn genes off in a more permanent way. The proteins from the gradient bind specific DNA sequences (found in the promoters of genes that need to be turned off in that cell type) and also bind enzymes that methylate DNA or modify histones. (I think that's what the "zone of polaring activity" comment was getting at)
I'd tend to agree with you. If environment influences how genes are expressed, it's only because the genome encodes the proteins and DNA elements that mediate epigenetics. It's worth treating seperate until more is known about how it works and it can be more incorporated with genetics, we must be careful not to make it sound like woo. A lot of this is due to the history - a lot of the guys who first pushed epigenetics seem to have been opposed to 'the central dogma.'
I don't think we've got enough data to answer those question yet. "Molecular Signals of Epigenetic States" is a good paper on this. If a mark is there, we know how it is maintained. How it's established is less known. Double stranded RNA (often from repetitive sequences that fold back on themselves) directs proteins to silence sequences complimentary to the dsRNA by marking histones and methylating the DNA. Proteins or RNA inherited in the cytoplasm can also direct the initial silencing.
The histones are removed and replaced by protamines in sperm development, so it's unlikely modified histones would be inherited from the father. Genome-wide DNA demethylation occurs twice in early development so it would seem inheritance of these states isn't possible. However, some marks clearly survive demethylation and histone replacement; imprinted genes are expressed differently depending on weather they were inherited from mum or dad and such marks can be inherited from the father.
Epigenetic marks are erased in gamete development and shortly after fertilization, as DNA demethylases are expressed and histones replaced with new unmodified ones. Some marks mar remain but the data isn't solid on that. The Agouti mouse and other models show some cross-gen inheritance but their ecological validity are questionable as the promoters have been artificially inserted in all cases I know of. My gut says it does happen but (unlike mitotic epigenetics) the evidence isn't solid so far.
It's hard to simplify this issue the way you do to something as understandable as this video. The heritability (through meiosis) of epigenetic marks isn't well established. New methods will give us a lot more info on epigenetics soon enough. I like how so many disparate mechanisms work together to regulate so many different processes. Differences in epigenetics between species make it hard to teach. Maybe some general principles (like a histone code) will come out of further research?
I think unassumption explained it better than I could. Here is a page with a bunch of topics and they are pretty easy to read. If you're interested, its a great source. nature(.)com/scitable/topic/gene-expression-and-regulation-15
I know too little about this for that comment to be helpful but thanks. (I have no idea what the zone of polarizing activity is in this context.) If you have time, I'd love to hear a more detailed explanation.
If this is Correct how is it that a fear of falling in dreams is so prominent and irrational fear of spiders, I assume that these fears are connected to our ancestors but only when they die and do not pass on any genetic material ...?
so my question is... Why the heck can we not get this quality classes in our classrooms across the globe? Instead of having most of our half@ss "science" teachers that read from a 50 year textbook, that clearly very few people understand. & find people like you, for the respective fields of studies in school.
Thank you! Great help to explain it to others. My MS kicks in when I eat gluten etc. I need no gluten/dairy/soy/sugar/GMO/food with a label/heated oils...take vitamins/good oils/minerals..probiotic...LDN..detoxing to be alright.
i realize epigenetics deals mostly with proteins and RNAs, but i always thought it should be portrayed as more of an extension of genetics it just seems to be talked about as this separate thing from the genome, rather than just how the environment (and ultimately DNA based regulation) influence the genome
This is not very accurate. It is the field (epi) that determines gene expression (genetic) since the DNA is not agential. This follows somewhat Einstein's famous saying: _"The field is the sole governing agency of the particle."
Very good quick video, thank you! Just one queston, can anyone please explain the mechanism by which certain cells determine which portions of the DNA to methylate and which lysine amino acids are acetylated. I find it very interesting how different cell type can identify which portion of the DNA gets unreadable. For example, in a heart cell, how is it determined which portion of the DNA gets methylated and which portion of the histones get acetylated so that only heart cell DNA is expresed? Thank you!!!
Hi Mr. Anderson, Thank you so much for making these videos! They are very helpful. One question here: the addition of a methyl group to cytosine causes the DNA to lose its affinity to its DNA binding proteins such as transcription factors at that site. Since transcription initiation requires two types of transcription factors (one bind to the TATA box and the other bind to the various regulatory sites of particular genes) to bind to a gene, the transcription factors can no longer bind to the methylated region, which means no mRNA can be formed, hence no polypeptides will be translated? Thank you in advance!
I legit made a RU-vid account so i could comment on this. Im watching this video for my Biology 115 exam. You are saving my grade and I thank you very much!!!! Sooooooo helpful
I never understood this: If you block a gene from being expressed, what gene is expressed in it's place? Wouldn't it be a wrong one, for example heart cell instead of skin cell? Is there an alternative healthier gene? It can't be nothing. If i have, let's say, a mutated finger and i block that gene off, what would be in it's place? I think is absurd that there would be no finger.
It all made sense at about 8:30 for me. I got here by way of a study that showed that induced behavioural traits in mice can be passed on to next generation mice - even when artificial insemination is used along with strict isolational environmental controls - a bit like Pavlov's dogs having puppies which salivate when they hear a bell - despite the puppies having been produced by artificial insemination in a different country. Nearly as weird as cannibal worms who inherit memory from worms they have eaten. I only found out about epigenetics today. Weird Science!
Also the one very drastic probably with that definition is that the DNA is not changed... How then dose it ever change from different organisms through mutation alone? I don't believe so. Epigenetics means above genetics. Ultimately we control genes and not the other way round
That's really really helpful for me. The concept of epigenetics was very confusing for me before. Now you make it super clear. Thannnnks very very much!
methylation can activate and also deactivate genes depending on place of methylation and degree of methylation. H3 K4 methylation is activation mark . H3 K9 is deactivation mark of genes.
Thank you for taking something as complex as epigenetics and making it easy to digest, especially for those who do not have a strong grasp on biology or physiology...my undergrad psych students thank you as well :)
I got a graduate certificate in clinical pathology and am now working on an MS in pharmacogenomics and I swear this guy should walk up for my diploma with me, because when I don't understand something I start here.
oh goodness i hope someone replies before my test, but is methylation reversible or is it only irreversible? there's been videos about demethylation but none with a super clear explanation that i've understood. and i understand that methylation is what keeps one of the two x chromosomes silent in females and becoming fatal, so that makes me wonder if demthylation can ever occur to make that other x chromosome appear once again??
In epigenetics, Ipso Facto, you are more related to your grandparents than your parents. This is because while your grandparents carry an "on" gene (let's say), it will be turned "off" in the next generation, then back "on" when you are born. That's why if you want to know more about yourself, ask your grandparents what kind of lives they lived when they were younger.
Ok, so the answer to my question boils down to "it's an area of current research". that's both slightly frustrating and exciting. Thanks for the paper. I'll read that as soon as possible and see whether it's on my level and answers some of my questions. Epigenetics is such an interesting topic.
I thought Dna Methylation would lead to increased transcription as it forms areas of " Z DNA". With Z-DNA being more loosely packed wouldn't transcription increase i.e.: euchromatinized genes? any explanation would be helpful
I see. So basically, the chance is slimmer but it's there. I really hope to hear more about Epigenetics on a level that can be taken by non-experts. - All I found on it were either fairly basic explanations around the level of this video or super technical papers way beyond my scope.
Great video ... now here's a man who understands epi enough to explain the genetics ... any "gut" thoughts on how to reverse epigenetic damage? Are there any suspected or known mediators? Thanks for the intelligence.
I am so glad I found you! The way you describe each lesson is so easily understood. I wish you were my teacher instead of the condescending one I have now.
Interesting... I haven't really any 'inherited sins' from my parents, i'm just not tolerable with acohol, eating too much white refined sugar etc. Thanks
