While researching a topic, a student has taken the following notes:While researching a topic, a student has taken the following...
GMAT Expression of Ideas : (Expression) Questions
While researching a topic, a student has taken the following notes:
While researching a topic, a student has taken the following notes:
- Tibetan mastiffs are large dogs native to the Himalayas.
- A mutation in their EPAS1 gene prevents excess hemoglobin production.
- A mutation in their HBB gene boosts hemoglobin's oxygen-carrying ability.
- These mutations enable the dogs to withstand hypoxic (low-oxygen) conditions at high altitudes.
- In a 2016 study, Zhen Wang and colleagues noted that Tibetan wolves' DNA has the same EPAS1 and HBB mutations.
- Wang and colleagues determined that the dogs first acquired these mutations by interbreeding with Tibetan wolves around 24,000 years ago.
The student wants to present the conclusion of Zhen Wang and colleagues' 2016 study. Which choice most effectively uses relevant information from the notes to accomplish this goal?
Like Tibetan mastiffs, Tibetan wolves can withstand hypoxic conditions at high altitudes.
Both Tibetan mastiffs and Tibetan wolves have mutations in their EPAS1 and HBB genes, which prevent excess hemoglobin production and boost hemoglobin's oxygen-carrying ability, respectively.
In addition to preventing excess hemoglobin production, a mutation in Tibetan mastiffs' HBB gene boosts hemoglobin's oxygen-carrying ability.
By interbreeding with Tibetan wolves around 24,000 years ago, Tibetan mastiffs acquired the genetic mutations that enable them to withstand hypoxic conditions.
Step 1: Decode and Map the Passage
Create Passage Analysis Table
| Text from Passage | Analysis |
|---|---|
| "Tibetan mastiffs are large dogs native to the Himalayas." |
|
| "A mutation in their EPAS1 gene prevents excess hemoglobin production." |
|
| "A mutation in their HBB gene boosts hemoglobin's oxygen-carrying ability." |
|
| "These mutations enable the dogs to withstand hypoxic (low-oxygen) conditions at high altitudes." |
|
| "In a 2016 study, Zhen Wang and colleagues noted that Tibetan wolves' DNA has the same EPAS1 and HBB mutations." |
|
| "Wang and colleagues determined that the dogs first acquired these mutations by interbreeding with Tibetan wolves around 24,000 years ago." |
|
Provide Passage Architecture & Core Elements
Main Point: Wang and colleagues concluded that Tibetan mastiffs acquired their high-altitude survival mutations through interbreeding with Tibetan wolves thousands of years ago.
Argument Flow: The notes start by establishing what makes Tibetan mastiffs special—their genetic mutations that help them survive at high altitude. Then they reveal Wang's key discovery: wolves have the exact same mutations. Finally, they present Wang's conclusion about how this happened: the dogs originally got these helpful mutations by interbreeding with the wolves around 24,000 years ago.
Step 2: Interpret the Question Precisely
What's being asked? The student wants to present the conclusion of Wang and colleagues' 2016 study specifically.
What type of answer do we need? A choice that effectively communicates what Wang and colleagues concluded, not just what they observed or what the mutations do.
Any limiting keywords? "Conclusion" is crucial—we need Wang's interpretation/determination, not just their findings or background information about the mutations.
Step 3: Prethink the Answer
- From our analysis, Wang's conclusion was specifically about how the dogs acquired their mutations
- They determined that the dogs "first acquired these mutations by interbreeding with Tibetan wolves around 24,000 years ago"
- This is different from just stating that both species have the mutations or explaining what the mutations do—it's about the origin story of how dogs got these beneficial traits
- The right answer should focus on the interbreeding process and timeline, showing how this explains the dogs' genetic adaptations
Like Tibetan mastiffs, Tibetan wolves can withstand hypoxic conditions at high altitudes.
- This just states that wolves can also survive at high altitude
- It presents what we can infer from the shared mutations, but not Wang's actual conclusion about how dogs acquired the mutations
Both Tibetan mastiffs and Tibetan wolves have mutations in their EPAS1 and HBB genes, which prevent excess hemoglobin production and boost hemoglobin's oxygen-carrying ability, respectively.
- This describes what both species have in common genetically
- It explains what the mutations do, but doesn't present Wang's conclusion about how dogs got them
In addition to preventing excess hemoglobin production, a mutation in Tibetan mastiffs' HBB gene boosts hemoglobin's oxygen-carrying ability.
- This only talks about Tibetan mastiffs and their genetic mutations
- It completely ignores the wolves and the interbreeding conclusion
By interbreeding with Tibetan wolves around 24,000 years ago, Tibetan mastiffs acquired the genetic mutations that enable them to withstand hypoxic conditions.
- This directly states Wang's conclusion: dogs acquired mutations "by interbreeding with Tibetan wolves around 24,000 years ago"
- It connects the interbreeding to the functional benefit