When a segment of DNA duplicates, causing two copies of a gene to be present in the chromosome, the duplicate copy could possibly (Check all that apply)

Question

_____  lose function due to mutation.
_____  become an ortholog.
_____  gain a new function due to mutation.
_____  become a pseudogene.
_____  become a centromere.

Clarify Question
  · What is the key concept addressed by the question?
· What type of thinking is required?
· What key words does the question contain and what do they mean?
 
Gather Content
· What do you already know about gene duplication?
 
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

__X__  lose function due to mutation.
_____  become an ortholog.
__X__  gain a new function due to mutation.
__X__  become a pseudogene.
_____  become a centromere.

Clarify Question
  · What is the key concept addressed by the question?
        o This question addresses gene duplication.
· What type of thinking is required?
        o This question is asking you to take what you already know and apply it to this unfamiliar situation.
· What key words does the question contain and what do they mean?
        o Duplication of a single gene or a segment of a chromosome means to create a second copy.
 
Gather Content
· What do you already know about gene duplication?
        o Duplication of a genomic region, either within a chromosome, or to another chromosome, allows genes with the same function to diverge because a “backup pair” of genes exist.
        o A duplicated gene can lose function; it is not selected against because there is another functioning gene, not just an allele.
        o The duplicated gene can also diverge and acquire new functions because the original persists.
 
Consider Possibilities
· Consider the different answer options. Which can you rule out?
        o Could a duplicated gene become an ortholog? No, because an ortholog is a copy of the same gene in another species, not within the same species. It could become a paralog though – a permanent copy of the gene.
        o Could a duplicated gene become a centromere? No, because centromeres have special DNA sequences that allow them to be recognized as such.
 
Choose Answer
  · Given what you now know, what information and/or problem solving approach is most likely to produce the correct answer?
        o Could a duplicated gene lose function due to mutation? Yes. This is possible because the other copy of the gene is still carrying out the original function. In fact it is the most common outcome.
        o Could a duplicated gene gain a new function due to mutation? Yes, this is also possible, again because the other copy of the gene is still carrying out the original function.
        o Could a duplicated gene become a pseudogene? Yes. It could acquire a mutation that makes it nonfunctional, but still linger in the genome.
 
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 can occur to a duplicated gene.
        o The question required you to take what you already know and apply it to this unfamiliar situation.
        o Did you recognize that a duplicated gene can more freely mutate, and either lose or gain function, because the other copy of the gene can carry out the original function.
        o Which two correct answers are really the same thing?