We have discussed the fact that unlike prokaryotic RNA, eukaryotic DNA must be spliced or processed before it achieves the status of mature mRNA.
The splicing event is peroformed by the spliceosome. A recent study highlights the importance of spliceosome components by showing that a rare genetic disease is caused by a mutation in a  |
| snRNPs the "smurfs" of cell biology |
So what is the purpose of introns? What overall function do they provide for eukaryotes? Why use such a complex splicing operation for a function which appears to do nothing more than rejoin exon regions? How do evolutionary biologists propose that snRNPs and spliceosomes evolved? Is this good design or is this entire process wasteful because large pieces of genetic material is discarded? Is this wasteful process, therefore, not supportive of the idea that splicing is a designed feature of cell life?
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| inTrons freed from the cell? what do they do now? |
due April 20
Introns serve an important purpose as part of the process of developing RNA and also to help make more proteins. The introns must be spliced in the RNA splicing process in order for the exons to come together and code for DNA sequences. They play a major role in cells because by splicing the DNA it allows for the genetic message to be received by exons so those cells would be able to read it before that certain protein is made. This makes it easier on the cell to prepare for the protein to be made.
ReplyDeleteThe overall function goes along with what I mentioned above. In addition to that concept they are relied on to sequence themselves in a certain order, so that they can make rRNA and be spliced to join the exons together, which contributes to transcription of DNA.
It may appear that introns do not do much, but they are contributing in ways that make it possible for DNA transcription to happen. God would not create anything to have no purpose, which means that introns do more than we would even know. With that said, I do not believe this to be a wasteful process because our Creator is right in all things and would not make a mistake in creating such an intricate process of life.
Evolutionary biologists say that snRNPs evolved from a common ancient ancestor (called the introns-early hypothesis) or they appeared in genes rather recently in the evolutionary process (called the introns-late hypothesis). Another theory is that the spliceosome and the intron-exon structure of genes is a relic of the RNA world (the introns-first hypothesis). There is still debate about which of these hypotheses is most correct.
Purpose and importance to eukaryotes: Introns are highly important to eukaryotic cells, because they allow for cell differentiation. They are what you have to start with, and depending on what you remove, the exons are what you are left with, and the exons are ultimately what determine the difference between your nose and your big toe, because they control which genes are expressed. The best way I can think of explaining this is like an old fashioned erector set or like a box of legos. The introns are all the legos together in the box. And out of that box of legos, you can choose certain legos and build a house or a helicopter or a space rover, etc. These legos in the final products would be the exons. Another example would be all the ingredients in a kitchen cabinet. Most kitchens have similar staples, like flour and sugar and baking powder and vanilla and butter and eggs, etc. But from those few ingredients, there is a near infinite possibilities of culinary creations you can make—like cookies or cakes or breads or soufflés. In this case, all of the ingredients would be the introns, but the only the ones used for that particular recipe, the ones that are expressed into, say, a cake, are the exons. But even though the exons are the ones that are actually expressed, you could not build anything if you didn’t have legos (or or make anything if you didn’t have flour and sugar and eggs, etc) to start with. They let us eventually have eyes and noses and big toes. Therefore, introns are VERY important.
ReplyDeleteWhy is this process so complex? Well, some people might look at a gigantic stained glass window in a church and say that it was a waste of time or money or space, but then they would miss the whole point. There might very likely be a scientific explanation for the complexity of this process, but the answer might simply be that God did it because He CAN. Because He can show off. Because, like the stained glass window, there is a sort of artistic mastery and beauty stamped into the complexity of the workings of SnRNPs upon introns. Because maybe it’s just one more of His ways of showing how laughable evolution really is.
As for how they supposedly evolved: I found a site online talking about the pros and cons of several theories. It described the intron-early and intron-late theories, and quite honestly, neither made a large deal of rational sense. I think even the scientists themselves realized this, because they smashed the good parts of both of these theories to form the intron-compromise theory. It also mentioned something about exon shuffling having to do with the evolution of introns. Yet, this made even less sense, since, don’t you have to have introns to get exons? So, how on earth could exons influence how introns came to be? Hmmmmm…..
Is this process wasteful? Not at all. The introns that are not used are then broken down and recycled and then used to start the process all over again. This is not inefficient, but highly efficient after all, and because it IS efficient, it points, once again, to intelligent design ☺
The exact purpose that introns serve isn’t completely understood. We know though that God has created everything with an exact reason. The human genome contains around 20,000 genes and someone those 20,000 genes account for the making of around 140, 000 proteins. If a certain gene has the DNA that codes for a certain protein how can 140,000 proteins be derived from only 20,000 genes if not less? This is where I believe that introns play a significant role in making protein. Alternative splicing is a process in which a single gene can code for more than one protein. Depending on what exact introns are spliced, it can result in a specific code for a specific protein. Using the same gene, a different section of introns could be spliced resulting in a code for a different protein. From what we understand now that may be the extent of the purpose that introns play in protein coding but there is always more information being discovered about genes. Evolutionists use the intron early and intron late theories to account for how snRNPs evolved but neither have sufficient evidence to be considered true. This process isn’t wasteful because introns aren’t wasted. They’re recycled and restructured into more gene sequences.
ReplyDeleteThe function of introns is currently not fully understood, but one proposed use of introns is that they enable alternative splicing, in which the same gene is expressed, but the protein resulting from the gene is different because of the introns remaining in the pre-mRNA, which change the product. Alternative splicing allows more varieties in the number of proteins made, so it probably gives eukaryotes more adaptability.
ReplyDeleteTheories presented for the explanation of the evolution of snRNP include the introns-early hypothesis, the introns-late hypothesis, and the introns-first hypothesis. The introns-early hypothesis assumes that the existence of introns began in an early, perhaps primeval, period, and that they evolved to what they are now. The introns-late hypothesis proposes that the appearance of introns is relatively new, as a result of evolution. The introns-first hypothesis guesses that introns and spliceosomes were developed by the RNA world, a world which was filled with ribonucleic acid that formed introns by chance.
The removal of introns may seem like a waste since it removes pieces of nucleic acids, however, even though there is “waste” made, it shows design from being able to choose which parts must be removed, and which parts of the mRNA must be kept. On the other hand, if introns had no function whatsoever, their existence is unnecessary and can be unanimously agreed to be a waste of materials.
Introns have a wide range of functions. Firstly, scientists theorize that introns were very important in early development of cells. Specifically in prokaryotes. Some would say they were around before exons, but then the prokaryote progressed and became more advanced. Meaning there was a need for diversification with the use of exons. Now an introns' modern job is to aid in proper mRNA transcript maturation.Studies provide evidence that mRNA with introns and exons produce more proteins than intron-less mRNA.It is unclear why exactly this is. If introns were originally the only genes to be expressed, then it is safe to assume that spliceosomes were "created" when exons were needed.
ReplyDeleteI think it is impossible to say whether or not this is good or wasteful design with the amount of knowledge we have. There is still a myriad of information yet to be understood. Not just about the intron/exon relationship, but the whole gene expression system. But perhaps the fact that it is so difficult to understand is what makes it an amazing design. If natural selection began with solely intron expression, then why waste time and energy evolving into intron/exon expression? Everything should be in the process to perfection, not degradation. With that said, this design does not take away from the functionality and necessity of the spliceosome.
Introns are not useless. Instead, there has been significant research that has shown that introns actually perform many different functions. Some introns end up coding for their own unique set of proteins, while others can be found as mobile genetic elements (aka. free flowing genetic material in the genome). They also are part of the RNA splicing that takes place when they are removed from the original RNA.
ReplyDeleteAlong with the aforementioned, these introns can be removed and also mixed and matched to provide a plethora of different options for producible proteins. This is known as alternative splicing.
This method helps provide the above unique abilities that an otherwise limited gene could not. The introns do provide a substantial amount of variation that can help improve life for the organism.
One theory I found on the evolution of snRNPs and spliceosomes deals with self-splicing introns. Evidence points towards this, it seems, as self-splicing introns in essence perform the same task the same way as snRNPs and spliceosomes. Thus, scientists like to point to this as evidence of evolution of snRNPs.
As to the wastefulness of the DNA splicing, even evolutionists tend to believe that there is nothing wasteful about the method as the benefits that come from introns outweigh the purported uselessness of introns.
When introns were first discovered, they were considered “junk DNA” since the introns were spliced out of the final mRNA that was used to make proteins. New discoveries show that this is not the case and new ideas on the purpose and function of these sections of DNA have been proposed. Introns produce greater variability in proteins by a process called alternative splicing. Alternative splicing is a process where one gene creates multiple proteins. This works by the interaction between snRNPs, spliceosomes, and introns. The splicing mechanisms are able to splice different exons together according to how they are separated by the introns. Sometimes, the snRNPs and spliceosomes choose to exclude exons. This causes a whole different protein to be produced by the same gene. This is one of the reasons why this complex splicing operation is more than just the rejoining of exons. It recognizes sites on the pre-mRNA strand to cut and places to rejoin to produce more proteins. Another purpose for introns is that they code for snoRNA. These are small nuclear RNAs found in the nucleolus where ribosome development occurs. They are believed to play a vital role in ribosome development. More research is needed in this area, but it can be seen by this new data and the diseases it causes that it is an important function of the cell. Some diseases that mutation in the complex causes are thrombotic thrombocytopenic purpura (causes microscopic clots to form in the small blood vessels throughout the body), Frasier syndrome, Atypical cystic fibrosis, and many more. This process is a good design because many genetic diseases would occur without it. It may seem wasteful, but one cannot confirm that all the introns discarded are not useful to the cell. There is still so much that is not known. One theory developed by Dr. Wilson is the idea that introns are an alternative DNA for a pre-fall world. This DNA would code for plant-eating diet that would have been seen before the fall in all animals and humans. This is just a theory, but it shows that there could be many purposes for introns that are not known yet. Evolutionists theorize that snRNPs and spliceosomes evolved from the integration of DNA from endosymbiosis and the transfer of genes between two organisms. Evidence has been found of self-splicing introns which evolutionists refer to as evidence for the evolution of spliceosomes in organisms. This entire DNA is not need, but has been collected over time and therefore needs to be cut out because there is no use for it as per natural selection. Some problems with this are that this process is so complex and decisive that just mere evolution from one to another would not account for the whole process. SnRNPs and spliceosomes need certain markers to splice. Genes have to have a marker and sites to show where the introns are to be taken out and exons put together. In the case of alternative splicing, how did the process of choosing which exons to use to create different proteins for one gene evolve? All these factors show the complexity of this process and show a designed feature for the splicing in cells.
ReplyDeleteIn eukaryotes, introns, even though they are discarded from RNA strands, are often used for other purposes. Many cells use introns to code for their own specific proteins. They can also be used to create noncoding RNA molecules after splicing has happened. This feature, known as alternative splicing, is used to generate several different proteins from one gene.
ReplyDeleteThis complex splicing operation does not just rejoin exons but rather it is able to go along the pre mRNA and figure out which ones to cut and which ones to keep, thus extending the number of proteins that can come from one gene. If this system was not in place, it would make the cell have to work so much harder to produce a protein that could seemingly be made by splicing one or two more exons. This is a much more efficient system system to develop proteins that otherwise would take much more time to build.
Evolutionists believe that snRNP's and spliceosomes developed from self splicing introns. While this theory sounds good, there is not much evidence that lends itself to supporting it. It is an extremely complex and unlikely scenario involving endosymbiosis and the fact that they think one intron caused an entire machine to be created is rather absurd.
I believe it to be good design. With the snRNP's and spliceosomes, we are able to distinguish between the exons and introns and thus create many different proteins from only one strand of pre-mRNA. These mechanisms create a more efficient way to make proteins. As far as it being wasteful, the fact that introns can be created into their own type of RNA, also means less waste and thus more efficiency.
Although introns were previously looked upon as having little function within the cell, they now have been found to have a role in most aspects of mRNA processing. One of the main roles of introns is to splice the same gene in ways so that a variety of proteins can be produced. This process is called alternative splicing. Introns also have sequences that are useful in efficient splicing. For these reasons, we see that introns are not complex merely to rejoin exons.
ReplyDeleteTwo theories involving the evolution of spliceosomes are the intron early hypothesis and the intron late hypothesis. The difference between these is ultimately whether the introns came about through common ancestry or whether they formed in genes later in the evolutionary process.
I would certainly not describe the function of introns and the process of splicing genes as wasteful. Instead the way introns splice genes is very elaborate and complex, and allows for variation in proteins.
Even though introns get cut out of the sequence, they can still serve a purpose. They are involved in the synthesis of new proteins or in the making of certain types of RNA.
ReplyDeleteTheir overall function is to be removed from the overall sequence by snRNP’s in order for RNA to be produced. They are heavily involved in the making of mRNA. Their removal leads to both the initiation and termination of the transcription process.
Although the function appears to do nothing more than rejoin exon regions, I believe that God designed this process to be complex to show His power and glory. Just because the function of introns is seemingly insignificant, I think that this shows God’s glory even more. God still has power over things which seem negligible, and which many times go unnoticed.
Evolutionary biologists propose that snRNPs evolved according to two hypotheses, the intron-early and intron-late hypotheses. The intron-early hypothesis claims that introns evolved from a common ancestor, while the intron-late hypothesis proposes that introns have only recently appeared.
This process is not wasteful because the genetic material is recycled over and over again, supporting the idea that splicing IS a designed feature of cell life.
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ReplyDeleteWhen I was researching the purpose of introns, the majority of the top results pointed to useless data that is thrown out through evolutionary processes. In this false theory, the species evolved overtime and didn’t need some of the sections of DNA, resulting in Introns. These were then offered as proof or “fossils” of the evolutionary process. These then needed to be removed in splicing by SnRnP to make usable mRNA. Yet in my research, one interesting result stood out. An article was writted by a creation scientist Dr. Jay Wile on the subject. In his article, he references this problem and explains a new discovery for Introns. According to Dr. Wile, the Introns serve as gene markers to code for individual protein. In his own words:
ReplyDeleteAt least one of the functions that introns serve is to separate the exons so that one gene can code for many different proteins… When the gene is originally copied, the introns and exons are both copied together, making the pre-mRNA. When the introns are removed from the pre-mRNA, the cell can use the exons as building blocks to make different proteins.
This theory is very viable. But another probable solution deals with cancers that we learned about in class. We learned that radiation from the sun can damage DNA. In Eukaryotes, for example, the amount of Introns is increased, reducing the likelihood of a used section of DNA becoming disrupted. In other words, these Introns work as defense mechanisms by reducing the probability of attack on critical regions. This explains the complex system for rejoining exons together after splicing.
In the evolutionary explanation of SnRnP and Spliceosomes, it is universally recognized that the genes to code for the process. This suggests that they were crucial from the beginning of their evolutionary processes. It is suggested that these two critical components originated as ribosomes and Group-II type Introns, according to Saba Valadkhan at the Center for RNA Molecular Biology.
This process is highly efficient when we process the facts. The Introns act as smart guides for the SnRnP to correctly splice, like small measuring sticks. This allows for a precise process that is energy efficient and specific to the requirement. Without markers, the system for splicing would be far more complex, having to contain its own measuring system. This system supports an amazing Creator who knew the special requirements within our nucleus better that we could ever grasp, and developed a specific system for that requirement. Our God is a gracious God beyond all comparison.
For years introns have been considered the "junk DNA" of a cell because they were chunks that were cut out. However scientists are now discovering that they do in fact serve a purpose in eukaryotic cells. When the introns are removed the exons are placed together in a new arrangement which mean they are capable of coding for more proteins. Basically a single gene can code for several proteins because they can be used like building blocks and placed together in different arrangements. The fact that introns are often referred to as junk DNA has been incredibly beneficial to revolutionary scientists. When introns were thought to have no purpose evolutionary biologists claimed that it was "fossil DNA" that no longer served a purpose. Unlike many cell organelles Scientists believe that snRNPs evolved from more sophisticated organisms. They're evidence for this is that snRNPs seem to be very well conserved.
ReplyDeleteUnlike many previous theories, it is now being determined that Introns are indeed an intensely vital part of cell transcription and translation. The process that determines the formation of necessary proteins is enhanced by the presence of the Intron. Basically, Introns provide the space between Exons that is necessary to allow genes to code for multiple proteins. Introns are essentially spacers in hnRNA. It is also being discovered that Introns may code for RNA called snoRNA. These RNAs are thought to be involved in ribosomal creation. This may be considered as another function of Introns in the eukaryotic cell.
ReplyDeleteAs for why such a complex unit is necessary to carry out such a basic function, think of it this way--a human arm moving appears to be a simple process, but think of all the molecule exchange and muscle contraction that goes into it. There are parts of physiology that simply seem more complex than necessary, but that must not be the case. God knows what He’s doing.
There are several different hypothesis floating around in cyberspace about the evolution of snRNPs and intron-splicing in general. One theory is that introns weren’t present in prokaryotic cells and just started showing up recently in eukaryotic cells. Another theory states that exons used to function as “minigenes” and eventually came together to form full, typical genes.
The whole process of RNA-splicing is not a waste, by any means. It has already been established that Introns do indeed carry out an important role in the cell. Large parts are discarded as waste in countless numbers of biological processes. I believe that cell splicing is, indeed, a designed feature of cell life. Of course it’s a designed feature--only THE designer has dominion over such processes.
It was initially believed that introns are leftovers holding no purpose at all. This belief is untrue however because without introns the sequencing for thousands of genes would be limited. When DNA is duplicated and mRNA is created it consists of these introns and extrons. The introns purpose is to act as a divider between the extrons which allows a single gene to code for different types of proteins. The introns thus allow the extrons to be spliced in different ways. Evolutionary biologists are divided over the subject of how snRNP’s and spliceosomes evolved. There are two main theories those being, the intron early hypothesis and intron late hypothesis. What differentiates these theories is whether introns were created from a common ancestor or whether they started to appear in genes only more recently due to evolution. The design of introns is effective and not wasteful because once introns have done their job they are recycled for further usage. The design of introns is essential because without them there could not be as diverse an amount of proteins.
ReplyDeleteSo what is the purpose of introns?
ReplyDeleteIntrons are able to allow the splicing for a particular gene in different ways so that a gene can produce proteins in cells in many different circumstances.
What overall function do they provide for eukaryotes?
For eukaryotes, they are used for several purposes. They are sometimes used to make noncoding RNA after splicing. They are also used to code for proteins.
Why use such a complex splicing operation for a function which appears to do nothing more than rejoin exon regions?
God created this process for a reason and we may not know exactly why it is so complicated until we ask him face to face. Because the process is so complex, we can admire it more and really appreciate it. This is pretty much what previous students have said and I completely agree.
How do evolutionary biologists propose that snRNPs and spliceosomes evolved?
Many believe that snRNPs and spliceosomes were made from the introns that are able to splice themselves. It is very unclear as to where they really came from and it will be very interesting to find out the truth.
Is this good design or is this entire process wasteful because large pieces of genetic material is discarded?
It is a very good design and not wasteful because introns can be created into their own type of RNA. We are able to identify between the exons and introns and make different proteins from one stand of pre-mRNA.
Is this wasteful process, therefore, not supportive of the idea that splicing is a designed feature of cell life?
Splicing is a designed feature of cell life because it is a very beautiful complex process necessary for cell life.
Introns enable our 20-25,000 genes to code for the 120-140,000 proteins present in our cells. The splicing enables the DNA to be rearranged into sequences that make different proteins. Introns also code for snRNA, making them a vital component of ribosomes in the nucleolus. The overall function of introns is to separate coded DNA from this mostly “junk” DNA to give rise to various sequences of DNA. This complex splicing operation is evidence of highly sophisticated design, and I believe that this only shows God’s handiwork even more. He could have created a much simpler system for separating introns from exons, but He chose to display his glory with this in depth process. Evolutionary biologists have discovered RNA that codes for snRNA and splicesosomes in insects. The U6 snRNA protein is the most common in these insects, and there are only 13 variable sites in the 33 genes, making it conserved and dependable. They believe that transcription and translation of the U6 snRNA eventually gave rise to the mutation of the other snRNAs. I don’t believe that this process is particularly wasteful, since the introns do function to enable different sequencing of RNA and subsequently proteins. Since they also function to code for some rRNA, they are obviously not a complete waste. But I believe that this is even more cause for a Creator. If introns are seen as “junk” DNA, it would take a long time for eukaryotic beings to sort through this DNA and learn to take it out of RNA. The complex process that God designed gives even more credibility, because a system of snRNA molecules would take a significant amount of time to evolve among eukaryotic beings.
ReplyDeleteThe purpose of introns is still vague, but it has been found that they are not just “Junk DNA” they actually serve a purpose. Introns help with the splicing in genes, which allow certain proteins to be made. In essence the introns are like a barrier between, different exons that code for certain proteins. In the eukaryotic cell, they are used, as stated before, as a separation between exons and they get spliced out when a certain protein is required. They are also involved in the synthesis of certain RNA. Secular scientists believe that snRNP’s developed from self splicing introns, however there is still much more investigation about these introns that it can not be one hundred percent accurate. It may seem that introns serve no purpose, but God did not create things with no purpose. There must be something to these units that we have not discovered, but God knows why he designed this mechanism the way He did.
ReplyDeletePoor introns! Always cut from the mature RNA product, introns are removed via RNA splicing and never take part in the translation process. These strands of “garbage” genetic sequences are even defined by the Merriam-Webster Dictionary as “a polynucleotide sequence in a nucleic acid that does not code information for protein synthesis and is removed before translation of messenger RNA.” However, introns cannot be disregarded as a bothersome fluke in the genetic process. Indeed, these genes benefit the cell in a number of ways.
ReplyDeleteForemost, the introns allow for more diversity in allele frequency. Mathematically speaking, a larger primary transcript with both introns and exons will provide a wider variety of possible mRNA combinations. Thus, introns could help eukaryotes respond more successfully to their rapidly shifting environment. Although this process might appear wasteful, the extensive amount of introns is necessary for the thousands of responses a cell might need to make. The fact that God provides cells with the material for all the reactions they need underlines His incredible care and faithfulness.
The Lord even provides an intricate and effective method of governing gene expression. Known as splicing, this method of cutting out unwanted introns involves spliceosomes and snRNPs. Evolutionary biologists are at odds as to how these systems were first formed. Some suggest that modern cells inherited snRNPs and spliceosomes from some obscure common prehistoric ancestor while others believe that these mechanisms appeared more recently. It is much easier to assume that God designed these cellular devices specifically to manage gene expression.
An intron is a nucleotide sequence within a gene that is removed by RNA splicing while the final mature RNA product of the gene is being removed. Introns provide an opportunity for a particular gene to be spliced in several different ways. One is so that a gene can produce different proteins in different cells or under developmental circumstances. Another way, is that they act as a substrate for evolution, which means that they allow gene segments to be re-used so that new protein functions can evolve.
ReplyDeleteDNA is subjected to many kinds of mutations caused by chemical compounds or a physical cause. There is a high probability that the one which is subjected to the mutation is actually an intron. This allows a possibility for the eukaryote cell to survive from a genetic mutation.
The complex splicing operation examines the pre-mRNA to figure out which introns to cute and which to keep. This extends the number of proteins that can come from one gene. If this operation was not in place, it would make the process of producing a protein much harder than necessary. The complex splicing system is really much more efficient than what would have to take place if it was missing.
Evolutionists believe that snRPs and spliceosomes developed from self-splicing introns. There is now much evidence to support this idea, especially because the system is so complex. It would be highly unlikely that one intron created an entire machine.
This is a good design because it allows us to distinguish from exons and introns within the gene. With this feature, we are able to create many different proteins from one strand of pre-mRNA. With this system, there is more efficient way to create proteins.
Intron function has not yet been fully discovered but there are some purposes that are understood. They allow for the splicing of genes through alternative splicing. SnRNP’s are developed form introns or at least this is the theory that the evolutionist take. This theory is unlikely because there is not much evidence and such a process would be way to complex. As for if this complex is wasteful it is not introns that are used for the process are recycled and used again making it a highly efficient system but we should not be surprised since the creator is the one that made it.
ReplyDeleteThe purpose of introns are to provide alternative pathways for DNA expression as these portions of the code in one pathway functions as exons and in another pathway as introns allowing for greater protein variation. This is one of the functions of introns but besides the function of alternate splicing the introns are also believed to operate in frame shifting and possibly in base pairing as well. These complex splicing operations exist because the well being of the introns and the exons as a whole are dependent upon this mechanism so that if you messed up cutting one then you would impact the other so that there would be serious results if this mechanism wasn’t so fine tuned. This operation is complex because it is crafted by an all knowing God who is complex beyond words so it makes sense that someone who is complex would beget something that is complex.
ReplyDeleteEvolutionary biologist believe that snRNPs and spliceosomes evolved according to the introns early hypothesis, the introns late hypothesis or the introns first hypothesis. It is believed that these things functioned selfishly so they were conserved in the organism even though they may not directly benefit the host. I think this is a good design because it allows for a variety of proteins to be produced which is essential to the function of the cell so it serves to benefit the cell as a whole as the cell interacts with diverse environments so that the discarded genetic material is worth the cost of the function it performs. This idea is supportive of the idea that splicing is a designed feature of cell life because it is an effective way for the expression of RNA to adequately address the needs of the cell and the “extra material” is not wasted but it reused so that this process shows design in that it shows the intricate thought and attention to details that can only be seen in something created by a creator.
Intron is derived from a meaning of “a region inside a gene”. Intron is any nucleotide sequence and a non coded region in a gene. It usually locates in between exon; a coded region. During splicing process, spliceosome (made out of snRNPs) cut out intron and reconnect exons together to make mature RNA. And almost most of the time, intron would have a sequence of GU on the 5’ slice junction (Donor site) and AG on the 3’ splice junction (Acceptor site); intron link can vary tremendously. There are 4 identified introns: intron removed by splicoesome, intron removed by protein, self-splicing group I intron removed by RNA catalysis, self-splicing group II introns removed by RNA catalysis.
ReplyDeleteSo what is the function of the intron? As we can see, each exons on the DNA string are not all the same. They have different lengths such as 18s, 5.8s, 28s, and so on. This can give us an insight to its function. The exons are separated by the introns (so the introns serve as separation tools) and give exons with distinct identities (exon 1, exon 2, and so on). Therefore, with different exons, the RNA has the ability to make different kinds of mRNAs; this process also known as alternative splicing.
This process is complex and involved with large genetic materials are wasted away. However, I would say that it is not wasteful and the design is a good design. If the design is very simple then it might give a high chance for the virus/bacteria (or other substance that harms the cell) to be able to imitate the process and infect the cell. At the same time, if the splicing machine is very small, it will not have enough strength to protect itself from anything that might infect them.
Introns: they are the original components, the name of the changes when they are left behind as “exons”. They both are needed for cell differentiation by aiding the proper mRNA transcription, because what you remove is just as important as what is left behind. They both control what genes will be expressed and which one won’t which gives us individuality of the parts of the body. The complex splicing has a process called alternative splicing where a single gene is capable of producing multiple proteins and place them in a different arrangement to display different outcomes. This outcome is able to happen because of snRNPs and spliceosomes removing the introns and leave behind the exons allowing a different protein to be created by the same gene. Introns have always been thought by evolutionist theorists to be considered significant in the development of a cell. That when the prokaryote were advancing from one organism to another the snRNPs and spliceosomes were needed for them to evolve. Natural selection plays into this so that the DNA of the snRNPs and spliceosomes allowed the “best” exons left behind would create a more enduring organism. In this whole process they would have needed to be created before the exons. We can’t claim that this whole process is wasteful, because we don’t fully understand the complete discarding of the introns. In class as Dr. Wilson brought up and Danielle mentioned that they might be completely a God gift so that when the fall happened, the DNA for the diet of pre-carnivore animals were able to change over to become carnivores.
ReplyDeleteThe purpose of introns is that introns provide a chance for a specific gene to be spliced (alternative splicing) in several different ways. Therefore, gene can code for more than one version of a protein; it can produce different proteins in different cells or under different developmental circumstances. Also, introns allow gene segments (that code for particular protein domains) to be reused so that new protein functions can enhance.
ReplyDeleteOverall function that introns provide for eukaryotes is to splice at different junctions to result in a variety of mature mRNAs and proteins. This alternative splicing allows for proteome diversity that much exceeds the number of genes in the genome. In addition, introns not only passively allow for alternative splicing because of their mere existence, but also actively regulate splicing by hosting splicing regulatory elements. Consequently, the existence of multiple mRNA transcripts within single genes may account for the complexity of some organisms, such as humans, that have relatively few genes.
Such a complex splicing operation for a function which appears to do nothing more than rejoin exon regions is used because complex assembly is guided by consensus sequences at the ends of the introns. This leads to the importance of accurate splicing that is illustrated by the fact that at least 15%, and perhaps as many as 50%, of human genetic diseases arise from mutations either in consensus splice site sequences or in the more variable auxiliary elements known as exon and intron splicing enhancers (ESEs and ISEs, respectively) and silencers (ESSs and ISSs, respectively). Thus, this is the way of preventing such a mutation and God’s purpose which He brings a life to us in order to glorify only Him forever.
Evolutionary biologists propose that snRNPs and spliceosomes evolved by accessing these two theories; “intron-early” theory and “intron-late” theory. Nearly all eukaryotes have introns and share mechanisms of RNA splicing, splicing itself must be quite ancient. Proponents of the "intron-early" theory suggest that all organisms (including prokaryotes) at one time had introns in their genome but subsequently lost these elements, while "intron-late" theory explains that the restriction of introns to eukaryotes suggests a more recent introduction. Therefore, evolutionary biologists believe that the theories which describe introns and splicing have clearly played a significant role in evolution approach to the evolution of snRNPs and spliceosomes.
This entire process is good design and not wasteful. It can continue along with the main transcription of the protein-coding portions of the gene. It automatically releases each helper chain at just the right time and place which is to be useful. This is very important process of creating new own protein and supporting the cell. So, God already planned this process and this is one of His great works.
This is not wasteful process and splicing is a designed feature of cell life. Introns themselves encode specific proteins or can be further processed after splicing to generate noncoding RNA molecules. It is essential to contribute efficiency for continuing a recycle of genetic material, giving such a complex structure, and producing diverse proteins eventually. Thus, this is God’s amazing design with revealing His great power through this process and splicing.
Although introns might be known to be “vague” they actually play a very important role. Without their purpose being played out certain proteins would not be made after the splicing of genes takes place. Different proteins are coded through the different exons that must be formed by these introns. Besides this process they are also involved in the process of RNA. SnRNP’s are seen by different scientists to have evolved from pre introns that by nature formed into snRNP’s. Although it may seem like introns may just be existing but have no purpose, I believe that God must have allowed their existence to show how this process of gene splitting takes place. God ultimately makes all things in this world to display his honor and glory and these introns are not left out at all. It is God’s simple way of saying that all though most things he made might be complicated, there still are some things that don’t take much time to figure out, therefore allowing us to discover how all though God might be complex at times he might give us simple answers to many questions.
ReplyDeleteWhen first researching the importance of introns, I had believed they were in fact useless, discarded material that really just added another step in the process of creating a protein. However, that idea really bothered me, because all throughout God’s creation, it seems that everything serves a specific purpose. Our bodies have processes to regulate certain pathways in order prevent the wasting of energy; efficiency is seen throughout all of creation. My research did in fact confirm that introns are not coded for proteins; rather they just stay within the cell. Which is nice, because it totally would have rocked my little world. The research did however; shed some light as to what they really are used for. Exons have a direct impact on the expression of a gene. Introns code for specific proteins and can generate noncoding RNA molecules, such as rRNA and tRNA. Now this is huge because as we know, the inner portions of a ribosome are lined with rRNA. In listening to a lecture on DNA by Dr. Najeeb, a world renown physician and professor at Western University of Health and Sciences, he illustrates the idea that DNA determines RNA, RNA determines the type of proteins, the types of proteins within a cell determine the type of cell, types of cells determine what type of organ will be made. Assembly of those organs will determine what type of systems will be made and how the systems structurally and functionally work, will determine what organism you are. So although it all comes down to DNA, the type of tRNA carrying an amino acid that attaches to the ribosome and will determine the type of protein made, is all dependent on the presence of these noncoding RNA’s or ncRNA’s. Which are generated from the introns left behind after splicing. This process is not wasteful whatsoever; rather it is truly amazing that God created such an efficient and effective process. As to why it is so complex, it really comes down to God wanting it to be that way, because if He wanted it to be very simple and straightforward, He could have made it that way. It may just be another reminder of God’s glory and our lack thereof. Because we have yet to fully understand these complex processes that are going on every second in our bodies and really in all living things.
ReplyDeleteFrom what I was able to find on the internet, there are two main theories regarding the evolution of snRNP’s spliceosomes. Intron early and introns late, as can be seen by their names, one theory proposes the idea that they evolved from a common ancestor, while the latter, believes they have just recently come to be. Neither of the two theories has much evidence supporting their validity. The efficiency of these processes is incredible and cannot be attributed to anything but an intelligent designer, God.
Studies recognize introns as a genetic material that is vital for the cell. Some findings point introns alteration directly related to development of cancer. Also, introns are pointed to carry functional information. In the same way our appendix were pointed to be useless and today is known to have a certain function in our body, the introns are there for a certain purpose. All the process of separating the introns wouldn’t be there if it wasn’t important for something.
ReplyDeleteSome researches point that introns make alternative splicing possible, enabling a single gene to produce different proteins in different conditions. Also, the smaller RNA often delivered from spliced introns are pointed to be involved in regulating gene expression.
Eukaryotic cells have transcription and translation separately, enabling intron splicing to occur, but prokaryotes can’t have introns, since their transcription is coupled to translation process. Also, eukaryotes have mitochondria organelles which can provide enough energy for this process that requires a lot of energy input, but prokaryotes don’t have mitochondria.
For the evolution of spliceosomes and snRNPs, I didn’t really find anything that biologists point as fact, but only theories that I honestly didn’t understand them.
All the process involves complexity and any mistake can cause problems and harmful mutations in the cells. God creation is complex in minimum details, showing His perfection and glory. Because sciences are proving that introns are fundamental for some cell activities, it does support the idea that it’s perfectly designed for cell life.