Human Y Chromosome Finally Sequenced! Turns Out to Be Really Weird

spoiler a word turns out the Y chromosome is just as weird as we always thought it was because after decades and Decades of Human Genome Project genetic mapping revealed that the sequence here is just not really what anyone expected the complete sequence of human Y chromosome revealed that it's just weird no better word to describe it but not like alien weird or like oh my God biology is wrong weird more like it just doesn't really make sense in order with different ways and an award of different structures but anyway a wonderful person this is Anton and today we're going to be discussing some of the new discoveries about the Y chromosome and also discuss another study in regards to animals that have lost our Y chromosome and in some sense are still surviving just fine and so we're also going to try to answer the question of are humans losing Y chromosome and what's going to happen to humans when there is no why left around and so let's discuss this in a little bit more detail but I guess let's start with the obvious Human Genome Project even though it's technically finished is not finished despite a lot of different mapping that's already taken place and despite solid understanding of what's happening in our genes there are still a lot of Secrets left here and still a lot of unanswered questions including questions about junk DNA now that's something we'll talk about in some of the other videos but there are still some things here that we still do not understand completely and one chromosome that was particularly challenging to map turned out to be the Y chromosome the smallest of them all and so even though a few years ago in the video in the description I've discussed some of the recent details and some of the recent discoveries about the Human Genome Project it took a few more years and additional techniques to finally finish everything including the Y chromosome the chromosome that unlike other chromosomes doesn't actually contain that many genes its main purpose is to determine birth sex in humans and other similar mammals and so if the embryo acquires X and Y chromosomes it take technically becomes male because it contains a trigger known as sry Gene sex determining region y protein that sort of looks like this that's responsible for switching on so-called male genes on other chromosomes one of the most important one is known as sox-9 Gene the gene responsible for the development of testes but this can be activated by other genes in other animals and so technically this particular protein is not really required but it seems to be pretty efficient and that's why Y chromosome begins sort of the feature a lot of different mammals acquired although none of this seem to have existed approximately 150 million years ago back then X and Y were just ordinary chromosomes the way they are today in for example birds birds don't have the same sex chromosomes as us and there used to be two copies of the Y chromosome that contains approximately 1 000 genes as well but it's believed that around this time this is when SRI being evolved and that's when this protein became extremely efficient at activating sex genes and at this point the Y chromosome started to change quite dramatically various types of limitations led to a dramatic change of Y chromosomes making them degenerate really fast losing approximately 10 percent of all active genes per million years basically reducing a number from approximately 1000 active genes to just 27. here's roughly what it looks like now compared to the X chromosome and because of this dramatic loss of genes it was always assumed that eventually we might actually lose Y chromosome completely I mean obviously it has the genes required to make sperm and even some genes critical for life if you look at the bigger picture copies of similar genes exist on the X chromosome as well it is for the moment y seems to do a pretty good job but one of the main reasons it was so difficult to actually try to read this chromosome or to try to map it is the fact that it's basic quickly full of junk DNA nevertheless the new study managed to sequence most of it uncovering that it tends to contain multiple copies of similar white genes including genes responsible for sperm generation and genes responsible for testes but for some reason some of these genes occur in very strange Loops where the sequence seems to be inverted or strange Loops where genetic accidents can sometimes duplicate or even erase genes in other words its structure kind of makes very little sense it's as if it's meant to be somewhat fragile and somewhat easy to mutate and potentially make mistakes it also contains enormous amount of structures that contribute to pretty much nothing once again junk DNA where there are quite a lot of Highly repetitive sequences that actually seem to be even coming from different viruses or genes that haven't been used for millions of years now that's common in the X chromosome 2 but particularly common in the Y chromosome remember this has at least a thousand active genes this one here only has 27 and then strangely enough it also seems to have a really large chunk of glow in the dark jeans different types of structures that tend to bind fluorescent dyes why this is so is currently unknown but then it also contains a somewhat pseudo-autosomal region that's sort of like a Remnant from when it used to be similar to The X chromosome and in some cases it's identical to some parts of the ax so when it comes to genetics it's almost like the Frankenstein's monster of chromosomes It's a combination of everything all together but also the one that seems to make the least sense but one question that a lot of scientists are trying to answer right now is so what's the future of the Y chromosome where is it actually headed now different independent studies on genetics usually using Multicultural samples have already detected that as you get older Y chromosomes tend to generally disappear and more importantly there is generally a sign of radiation in older bodies and because of this there have been actually several speculations that maybe at some point in the next 10 million years the Y chromosome might be gone completely now this is a somewhat controversial statement and it's not really scientifically proven just yet but it's still something worth assessing because there are definitely signs of the Y chromosome decreasing in overall size and also decreasing with age and so the question is can it completely disappear and what would happen to the species then turns out it's happened before to several rodents in the last few million years and though technically losing Y chromosome May mean the loss of sexual reproduction it doesn't seem to be the case at least for a well-known case of a mummy spiny rats they seem to have found a way to regress back to what it used to be like approximately 150 million years ago evolving X chromosomes into new male sex chromosomes these rats though kind of rare are quite common at least on some islands in Japan and they all seem to possess Just One X chromosome inside their body both males and females but it wasn't always like this genetical studies determined that they used to have Y chromosome but just like in mammals and just like in humans it's basically disappeared over time and specifically approximately 2 million years ago certain types of duplication inside X chromosome were suddenly able to perform the same role as the Y chromosome in their ability to turn on sox9 factor which meant that they no longer required sry Gene that's present on the Y chromosome as a matter of fact it's believed that both were used by certain species but over time it is possibly became redundant and so it's possible that as the Y chromosome started to shrink there was maybe a mixed population of males with and without y they were done compete for resources but around the same time there was also a relatively major climate change which dramatically raised the sea levels reduce using the size of the islands and thus resources available and then for some reason the Y chromosome rats died out the X chromosome remained it could have been just luck or it could have been something specific about the X chromosome that allowed them to thrive better and they seem to be doing just fine basically inside their X chromosomes the male sex will usually have a lot more duplicated regions that tend to boost the activity of these sox9 Gene which leads to the male development whereas the female mice will often not have any duplication of certain regions and thus remain as female so basically it's a really simple adaptation that most likely exists in humans as well although maybe it's just not expressed as well yet because our genes are just more complex nevertheless if the Y chromosome one day disappears this is maybe one way that all this could progress as well but when it comes to the bigger question of is this also our future the answer is not really as clear first of all it still looks like the Y chromosome is doing fine for now as a matter of fact most mammals seem to have the Y chromosome and it's not really disappearing yet but since the Y chromosome is shrinking with time it's really just a matter of chance before something might evolve on the ax that can basically perform the same rules as the Y chromosome is performing right now and once that does happen well yeah at that point there's no point to have wire so it's probably going to disappear pretty quickly now if that actually happens or not that's not a question we can answer in those rats that I mentioned it was basically a result of some kind of a pressure from the outside and that's not really something we have right now as humans as a matter of fact most mammals with the Y chromosome may not have similar pressures for quite a long time either and since Sr YG is so efficient at activating the sex genes it might still stick around for some time so in the end the answer is I don't know nobody knows it's possible it might disappear or it might stick around for some time what is pretty clear though based on the recent analysis and the recent mapping of the Y chromosome is that it's just really weird so much more unusual than anyone thought and has so many different unusual features and unusual qualities including unusual sequences that currently do not make sense which means that we're probably going to be coming back and talking more about all of this once there are additional studies and more discoveries for now the mystery of the Y chromosome remains kind of unansweried it's tiny it definitely shrunk over time but it might stick around for some time anyway at least for now that's pretty much all I wanted to mention all of the studies are in the description below check out the previous video on the Human Genome Project and its successes thank you for watching subscribe share this with someone who loves learned about space and Sciences come back tomorrow to learn something else super Legends or by buying the wonderful person t-shirt you can find in the description stay wonderful I'll see you tomorrow and as always bye [Music] thank you foreign

Channel: Anton Petrov

Views: 829,884

Keywords: anton petrov, science, physics, astrophysics, astronomy, universe, whatdamath, what da math, technology, steven universe, space engine, universe sandbox 2, t2t, telomere, telomere to telomere, telomere 2 telomere, human genome, human genome project, sequenced human genome, entire human genome, human biology, hgp, genomics, genes, human genes, chromosome, human chromsomes, centromere, molar pregnancy, hydatidiform mole, hydatid mole, mola hydatidosa, y chromosome

Id: iUjUeQjMkpo

Length: 12min 39sec (759 seconds)

Published: Sun Sep 03 2023