The timing of a mutation during development has negligible effects on the severity of the genetic defect.

Question

Answer the following statement true (T) or false (F)

Answer 1

False

Clarify Question

What is the key concept addressed by the question?
The question is asking about the timing of mutations during development and the effect of the timing on the mature organism. 
What type of thinking is required?
You are being asked to analyze a statement about when mutations occur in the human life cycle and assess the possible differences in severity of the resulting genetic defect. 
What key words does the question contain?
Mutation, permanent, random changes in genetic material 

Gather Content

What do you already know about chromosomal translocations? What other information is related to the question?
What is a mutation? What are possible results of a mutation on a protein? On an organism? If a mutation occurs in a zygote, would that have a different effect on the organism than if the same mutation occurred in a somatic cell of an adult organism? Why or why not? What happens to the nuclear DNA at each cell division? 

Choose Answer

Given what you now know, what information is most likely to produce the correct answer?
You have to decide whether or not when, during development, a mutation occurs makes a difference the severity of a genetic defect. Let's imagine a devastating genetic disease caused by a mutation in gene A. If that mutation in gene A occurred in one of your somatic cells, would it have an effect on you? Maybe some, maybe a little, maybe not. Not all somatic cells express the same genes, so the mutation may be in a gene that is not even expressed in that particular cell type. All cells that arise from a somatic cell are of the same cell type, and barring any issues with cell cycle regulation, that line of cells should not divide indefinitely. Basically, even if a mutation does affect some cells, it won't affect all, at least immediately. Now what if that same mutation occurred when you were a zygote. When that zygote divides, the DNA ends up in both resulting cells, mutation and all. And then in the next round of daughter cells. And the next round. And so on-all cells of the organism would have the mutation that occurred early in development. So which would be more likely to be devastating and severe-having a defect in all cells because the mutation occurred early in development, or having the mutation in a subset of somatic cells of an adult organism? If the mutation happened early in development, say in one cell of an eight cell embryo, every cell derived from the mutant cell would have the mutation. Because mutations early in development have the potential to impact development more severely than mutations later in development, this statement is false. 

Reflect on Process

Did your problem-solving process lead you to the correct answer? If not, where did the process break down or lead you astray? How can you revise your approach to produce a more desirable result?
Answering the question depended on your ability to discern if the timing of mutations during development could affect the severity of a genetic defect. 
If you got the correct answer, great! If not, remember it's important to use a systematic approach to answer questions and to reinforce those good habits over time. If you got an incorrect answer, where did the process break down? Did you understand that a defect in early development would affect many more cells than if a mutation occurred in somatic cell of an adult? Were you then able to understand that if more (or even all) cells carried a mutation, the genetic defect would be more severe? And then were you able to relate that to the question and understand that the timing did NOT have negligible effects?