Hox genes are a family of transcription factors that regulate development throughout the animal kingdom. Studies of Hox genes in mice and Drosophila showed that many Hox genes are conserved between both species, and several Hox genes duplicated into new genes with novel functions within mice. Some Hox genes have even lost all function. Hox genes provide an example of which of the following? Check all that apply.

Question

_____  orthologs
_____  paralogs
_____  heterologues
_____  pseudogenes

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 homology?
 
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__  orthologs
__X__  paralogs
_____  heterologues
__X__  pseudogenes

Clarify Question
· What is the key concept addressed by the question?
        o This question addresses homology.
· 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 Transcription factors are genes that regulate the transcription of other genes.
        o Drosophila is the genus name for the fruit fly used in genetics research.
 
Gather Content
  · What do you already know about homology?
        o Homologous genes arose from one original gene.
        o There are two kinds of homology: paralogy and orthology.
        o Two genes within an organism that have arisen from the duplication of a single gene in an ancestor are called paralogs.
        o In contrast, orthologs reflect the inheritance of a single gene from a common ancestor — a conserved gene.
 
Consider Possibilities
· Consider the different answer options. Which can you rule out?
        o Are the Hox genes an example of heterologues? No, that is not a term. They are examples of homologues – related genes.

  Choose Answer
· Given what you now know, what information and/or problem solving approach is most likely to produce the correct answer?
        o The similar genes in different species are examples of orthologs.
        o The similar genes in the same species are examples or paralogs.
        o The nonfunctional genes are examples of pseudogenes.
 
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 concepts are exemplified by Hox genes.
        o The question required you to take what you already know and apply it to this unfamiliar situation.
        o Did you recognize that Hox genes include orthologs – the same gene in different species?
        o Did you recognize that Hox genes include paralogs – related genes in the same species?
        o Did you recognize that Hox genes include pseudogenes – genes that have become nonfunctional?