Question

Ellis-van Craved syndrome is an inherited condition affecting bone growth. The primary symptom is short stature. Other symptoms include abnormal numbers of finger and toes, and tooth and nail abnormalities. Some individuals with the condition have heart abnormalities.
The frequency of the condition in most populations is low. However, the condition occurs at a much higher rate in the Amish population descended from a group who migrated from Europe to Pennsylvania in the 1700's.
Which of the following explains the difference between the Amish frequency of the condition and the frequency of the population they migrated from?

• A. An early member of the migrant population was a carrier for the condition.
• B. Inbreeding in the migrant population caused new mutations leading to the condition.
• C. The difference in environment between Europe and Pennsylvania caused the Ellis-van Craved alleles to be selected for, increasing the frequency.
• D. The frequency of Ellis-van Craved syndrome had been higher in the worldwide population in the 1700's. The frequency stayed the same in the Amish population while decreasing in the rest of the world.

Answer 1

The correct option is A An early member of the migrant population was a carrier for the condition.

As a small group of population migrated from the original population, some of the individuals carried the gene for the syndrome. Which got amplified as the mating occurred in a small population. So the number of individuals with the condition was higher in the Amish population.

So, the correct answer is 'An early member of the migrant population was a carrier for the condition'