The alpaca was domesticated by Indigenous peoples in the Andes about 7,000 years ago. But which wild species did it...
GMAT Information and Ideas : (Ideas) Questions
The alpaca was domesticated by Indigenous peoples in the Andes about 7,000 years ago. But which wild species did it descend from, the vicuña or guanaco? A research team led by Ruiwen Fan may have solved the mystery, concluding that the alpaca is the domesticated form of the vicuña but that the modern alpaca gets only 64 percent of its genetic material from its wild ancestor. The rest comes from the domesticated llama. The llama, meanwhile, gets 95.5 percent of its genetic material from its own wild ancestor, the guanaco, and the rest from the alpaca. The llama and alpaca apparently interbred widely for only a handful of generations between 400 and 600 years ago. Assuming that the findings of Fan's team are valid, it can be inferred that ______
Which choice most logically completes the text?
modern llama populations have a greater degree of genetic diversity, on average, than modern alpaca populations do.
the domestication process of the alpaca may have involved some introduction of genetic material from the llama.
the period of interbreeding resulted in a greater genetic difference between alpacas and their wild ancestors than between llamas and their wild ancestors.
if they were subjected to genetic testing, modern populations of guanacos and vicuñas would likely show traces of ancient interbreeding as well.
Step 1: Decode and Map the Passage
Part A: Passage Analysis Table
| Text from Passage | Analysis |
|---|---|
| "The alpaca was domesticated by Indigenous peoples in the Andes about 7,000 years ago." |
|
| "But which wild species did it descend from, the vicuña or guanaco?" |
|
| "A research team led by Ruiwen Fan may have solved the mystery, concluding that the alpaca is the domesticated form of the vicuña but that the modern alpaca gets only 64 percent of its genetic material from its wild ancestor." |
|
| "The rest comes from the domesticated llama." |
|
| "The llama, meanwhile, gets 95.5 percent of its genetic material from its own wild ancestor, the guanaco, and the rest from the alpaca." |
|
| "The llama and alpaca apparently interbred widely for only a handful of generations between 400 and 600 years ago." |
|
Part B: Passage Architecture & Core Elements
Main Point: Recent research reveals that while alpacas descended from vicuñas, modern alpacas and llamas have mixed genetics due to interbreeding that occurred centuries after their original domestication.
Step 2: Interpret the Question Precisely
This is a fill-in-the-blank question asking us to choose the best logical connector. The answer must create the right relationship between what comes before and after the blank.
Step 3: Prethink the Answer
- The key data points are the genetic percentages: alpacas are only 64% similar to their wild ancestors (vicuñas), while llamas are 95.5% similar to their wild ancestors (guanacos)
- This means alpacas have diverged much more from their original wild form than llamas have
modern llama populations have a greater degree of genetic diversity, on average, than modern alpaca populations do.
✗ Incorrect
- Claims llamas have greater genetic diversity than alpacas
- The passage gives us genetic similarity to wild ancestors, not overall genetic diversity within populations
the domestication process of the alpaca may have involved some introduction of genetic material from the llama.
✗ Incorrect
- Suggests genetic mixing happened during the original domestication process
- The passage clearly states interbreeding occurred 400-600 years ago, not during the original domestication 7,000 years ago
the period of interbreeding resulted in a greater genetic difference between alpacas and their wild ancestors than between llamas and their wild ancestors.
✓ Correct
- Alpacas are only 64% genetically similar to vicuñas while llamas are 95.5% genetically similar to guanacos
- This means alpacas have diverged more from their wild ancestors than llamas have
if they were subjected to genetic testing, modern populations of guanacos and vicuñas would likely show traces of ancient interbreeding as well.
✗ Incorrect
- Makes claims about wild species showing interbreeding traces
- The passage only discusses genetics of the domesticated species