Finally! An inversion video which clearly describes the ramifications in meiosis and crossing over. Just what I needed for my midterm. Thank you! Amazing video!
My daughter has this inversion. Chromosome #9 broke off and reattached itself at the bottom. Was told at 4 months preg. I should probably think about abortion. So happy I choose to let nature take care of itself.
*Thanks for very easily explaination sir 😊* *I'm from India and basically knowing* *Hindi language well but i understand from this video easily.* *Very very thanks for easily explaination 😊*
The Acentric chromosome fragment you drew that would not produce a gamete, contained genes D, G, and H of the green strand. Wouldn't this Acentric chromosome also contain E, F, G, and H of the red strand, forming HGDEFGH?
Krithika. I currently do not have a video on pericentric inversions. However, you would set it up the same way as a paracentric inversion (except of course with the centromere in the inversion loop) . Then just follow the chromosomes from one end through the crossover. As with paracentric inversions, there is only a problem if there is crossing over in the loop. If no crossing over then there is no issue. Unlike paracentric inversions with crossing over, pericentric inversions do not produce dicentric or acentric chromosomes they produce chromosomes with too much or too little chromosomal material. Good luck.
Steven Gorsich: I just finished my quiz and there was a paracentric inversions question just like this asking for all gametes and their viability. I wouldn’t have got it if it weren’t for me watching this great video the night before :)
Thank you Steven for your great video. But I have one question. How this inversion form in the first place? From your video about duplication and deletion, I can understand how they form during meiosis crossing over. But how about inversion? I guess the mechanism is much more complicated.
Not really more complicated. Inversions are causes by the chromosome getting cut twice and the middle portion flipping 180 degrees. This is often caused by various mutagens (like X-rays) that are known to cause double strand breaks. They are also incredibly important evolutionarily because they can cause gene mutations and can lead to new genes or altered gene expressions. Hope that helps.
Steven Gorsich thank you for your prompt reply. So after double strand break, i have a question about how it “stick back”? is it a simple 180 degree flip and join by ligase? It would require a +/- chain switch right? Or is it by homologous recombination?
Can you please explain about chromosome 9 pericentric inversion. My partner has it. What are our best bets for healthy kids? Should we do ivf with preimplantation genetic testing? (I had 2 miscarriages and no kids yet) Thank you for your work and effort!
This is actually a fairly common inversion in humans (up to 3% of the population). This can lead to infertility. However, after my name is a PhD and I should not give out medical advice. I do think it's important that you talk with a genetic counselor and your OB. They will be able to give you a more precise answer and should be able to tell you if there are any ways to overcome the infertility. Luckily (speaking from first hand experience) there are other great ways to be a parent. Hang in there and good luck to you and your partner. I hope to hear good news in your future.
Good question. I'm going to give you an answer off the top of my head, and lead you in a direction that might be helpful. In case this is an homework question, I don't want to give you the answer. Remember with paracentric inversions that there are usually no problems as long as there isn't a crossing over event in the loop. Now, if there is a crossing over in the inversion loop then it becomes more interesting. Remember, one of the gametes that forms is a dicentric (having two centromeres) chromosome. What becomes of this? Could this lead to a trisomy or monosomy? I could see an argument for an aneuploidy or no aneuploidy. One is more correct. What do you think?
Please stop saying synapse, it's not healthy for us to cringe this hard. Complementary base pairing is its own phenomenon. The word "Synapse" in biology is used explicitly and exclusively as an implication of a neuronal Axo- somatic/axonic/dendritic junction (i.e. a neuronal synaptic junction). It's not too big a deal I guess, as your context is very different and this doesn't hinder your capacity to convey your lecture (good video btw) But it's just incorrect terminology and it's best not to be passed on to students.
I now realize you might have been referring to Synapsis/ Syndesis. If this is the case you should use the terms correctly. Hope you don't mind the constructive criticism, even if you decide not to take my advice I still think your vids are very helpful and you have my gratitude regardless.
@@themadlad5577 Thanks Archie. Don't mind at all. I often say synapse as a verb describing synapsis. I don't know if using it as a verb is correct, but I think it's probably ok. When I remake this video I will keep that in mind. I do appreciate how if someone is coming from either the neurobiology field or the cell biology field that the noun synapse means something different. Have a good one.
