Which of the following should be the same in identical twins? a. the set of antibodies produced b. the set of MHC molecules produced c. the set of T cell antigen receptors produced d. the set of immune cells eliminated as self-reactive

Video transcript

Welcome back. Let's look at our next question here, why do identical twins have the same set of MHC molecules? Well, we recall from our content videos, MHC molecules are the major hist o compatibility complex, There's type one and 2 um and they're part of what they're very specific to the individual. They are inherited from parents and they basically help identify cells as belonging to yourself versus being foreign. So, a really important part of the immune system, as it helps your immune system recognize which cells are foreign and should be destroyed. And of course, an issue with things like organ transplantation. Um as you can't get an organ from someone with different MHC molecules or it'll be attacked by the immune system. So let's think about our question here, why do identical twins have the same set of MHC molecules? So let's work through our answer choices here. Choice A says because they came from one zygote causing them to have the same DNA and this is correct. Um MHC molecules are very specific and they are inherited so identical twins which result from a single zygote splitting into have the same D N A and therefore will inherit the same exact set of MHC molecules. So this is the correct answer choice A but we should look at our other answers to really understand this choice B says because they inherit their MHC molecules from the same set of parents? Well, this is not true because all siblings inherit their Emmett or full siblings inherit their MHC molecules from the same set of parents, but just like any genetic inheritance, they don't necessarily inherit the same set. Um Because they inherit half the genes from the father, half from the mother. And they can be different genes inherited just as siblings can look different, different eye color, different hair color. Um They could inherit different MHC molecules even though they have the same set of parents. So this doesn't explain why identical twins have the same set. That's because all of their D. N. A. Is the same. So Choice B not a correct answer, Choice C. Says because they grew up together in the same environment again, MHC molecules are inherited their inborn not affected by the environment. So Choice C. Is incorrect. And finally, Choice D. Because they adopt similar lifestyle and diet. Again, we're talking about in born genetically inherited trait, so Choice D. Is not correct. So again, identical twins have the same set of MHC molecules choice A. Because they came from one zygote and therefore have the same D. N. A. Thanks for watching. See you in the next video