Two eukaryotic proteins have one domain in common but are otherwise very different. Which of the following processes is most likely to have contributed to this similarity? a. gene duplication b. alternative splicing c. exon shuffling d. random point mutations

Video transcript

hi everyone. Our next question says and you carry outs. Exon shuffling is a molecular mechanism responsible for and we have choices of a similarities in the domain of two different proteins. Be differences in the domain of two different proteins. C random point mutations or d frame shift mutations. Well excellent shuffling does cause a mutation in a gene changes to a gene. Um But we're first actually going to look at our last two choices and show why they are not correct. Go ahead and eliminate them. So random point mutations as you can recall from another video or when we have a D. N. A sequence in which we have a single nucleotide that is mutated or changed. So let's say this a here changes to a. T. So a point mutation there. Now eventually when we go through the process of transcription and translation uh let's say these three base pairs end up um The M. R. N. A. That is transcribed from them codes for a code on. And perhaps this change to A. T. Here now causes that code on to result in a different amino acid in the protein. So you'll end up with a change a mutation in your protein. Um It might not because this might not change the code on but that is a random point mutation which is not exon shuffling. So we can eliminate choice see and frame shift mutations are and will recall when we have our D. N. A. Sequence and we have either the addition or the deletion of a nucleotide. So we'll say that we have the addition of a G. In here. And as a result, now, if we look back at our three base pairs that are going down the line, B N. M R A R. N. A. Code on now instead of C. A. A. We have C. G. A. But it also affects the following code ons because originally this one began with A. T. And then had to following nucleotides but it now begins A. T. And then has nucleotides. So this shifts the sequence of code owns down the line and has the potential to impact all the amino acids. After this frame shift. It's a large mutation but it's still not exon shuffling so we can eliminate choice D. So now we're just going to decide whether we have a similarities or be differences in the domain of two different proteins. So to help out and help us decide this, we're just going to look at a diagram of an example of exon shuffling here and excellent shuffling can occur um either through transpose eons through crossover events during sexual reproduction or what's called illegitimate recombination. So here we're just going to look at a little example of crossover in reproduction. So we've got two genes, gene one with three different Exxon's colored in red, yellow and pink and jean two with three different Exxon's blue, green and orange and we're going to say that we had a crossover event here in this region. And as a result of these two regions swapping, we now have a new gene three and it has three. Exxon's similar to jean to but now additionally has this yellow X on to that originally was in Gene one. So, if we look at the proteins produced after these genes have been transcribed and then translated, Well, gene one codes for a protein that has these three regions red, yellow and pink from its three Exxon's gene. Two codes for this protein with the blue, green and orange regions encoded by those exxons. And now we have protein three similar to protein too. We have these blue, green and orange but we now have this yellow portion. That is the same as this portion in the different protein one. So these are two different proteins with this similar region to them due to that crossing over. So that leads us to the answer that exon shuffling leads to a similarities in the domain of two different proteins and not be differences. So, our correct answer is a and we'll hope to see you in the next video