What genetic defects result in the disorder xeroderma pigmentosum (XP) in humans? How do these defects create the phenotypes associated with the disorder?

Video transcript

Everyone. Let's take a look at this question together which of the following DNA repair pathways is affected in zero derma pigmentosa. So let's recall what we know about what zero derma pigmentosa is as well as what the different DNA repair pathways are to figure out which one is affected and zero derma pigmentosa. So looking at our answer choices, we can see several different DNA repair pathways. Let's refresh our memory on what each of these are to try to figure out which one best represents the pathway that is affected in zero derma pigmentosa. Well homologous recombination we know refers to repairs in the double strand brakes after replication. And we know that non homologous and joining is the pathway that connects two broken and together. And we know that nucleotide excision repair repairs damages that distorts the D. N. A. Helix. And lastly base excision repair removes and replaces damaged nuclear ties. And so now that we know what each repair pathways responsible for. Let's try to figure out which one is affected in zero derma pigmentosa. So we know that the zero derma pigmentosa pinot type is caused by defects in the N. E. R. Pathways as well as mutations get more then one bean. And so because it is caused by those defects in the N. Er pathways that means that the DNA repair pathway that is affected in zero derma pigmentosa them is answer choice C. Nucleotide excision repair or N. E. R. Because when we have those defects in the N. Er pathways which prevents it from repairing damage that distorts the D. N. A helix we have that zero derma pigmentosa um disorder. So answer choice C. Is the correct answer. I hope you found this video to be helpful. Thank you and goodbye.