What was the most significant research finding that resulted from the successful cloning of Dolly?

Question

A.  The key to cloning success is to pick a donor cell from very early in development.
B.  Cloned animals are capable of producing normal offspring.
C.  The nucleus of a fully-differentiated cell can be reprogrammed to be totipotent.
D.  Genetic imprinting, which occurs in adult reproductive tissue, can take months for sperm and years for eggs.

Clarify Question
· What is the key concept addressed by the question?
· What type of thinking is required?
of the possible answers.
· What key words does the question contain and what do they mean?
 
Gather Content
· What do you already know about cloning?
 
Consider Possibilities
· Consider the different answer options. Which can you rule out?
   Choose Answer
· Given what you now know, what information and/or problem solving approach is most likely to produce the correct answer?

  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?
 

Answer 1

C.  The nucleus of a fully-differentiated cell can be reprogrammed to be totipotent.

Clarify Question
· What is the key concept addressed by the question?
        o This question addresses reproductive cloning.
· What type of thinking is required?
        o This question is asking you to weigh and judge, or evaluate, evidence to choose the best of the possible answers.
· What key words does the question contain and what do they mean?
        o In this case, cloning refers to reproductive cloning – growing a new individual from a cell.
 
Gather Content
· What do you already know about cloning?
        o Cloning of Dolly was the first example of reproductive cloning.
        o It demonstrated that the nucleus of a differentiated cell could be “reprogrammed” to start over again as a totipotent cell.
 
Consider Possibilities
· Consider the different answer options. Which can you rule out?
        o Did Dolly’s cloning demonstrate that the key to cloning success is to pick a donor cell from very early in development? No, actually the cell used was a mammary cell from a six-year old sheep.
        o Did Dolly’s cloning demonstrate that genetic imprinting, which occurs in adult reproductive tissue, can take months for sperm and years for eggs? No, it did not address this issue.
        o Did Dolly’s cloning demonstrate that cloned animals are capable of producing normal offspring? Yes, she did have offspring. But this was not the most important aspect of Dolly’s cloning.
   Choose Answer
· Given what you now know, what information and/or problem solving approach is most likely to produce the correct answer?
        o Did Dolly’s cloning demonstrate that the nucleus of a fully-differentiated cell can be reprogrammed to be totipotent? Yes, this was the most important conclusion from the cloning of Dolly.

  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?
        o This question asked what we had learned from the cloning of Dolly.
        o The question required you to weigh and judge, or evaluate, evidence to choose the best of the possible answers.
        o Did you recognize that Dolly’s cloning demonstrated that a differentiated cell’s nucleus could be made totipotent?