Question

The ability to roll the edges of the tongue upward in a U-shape has been considered to be an inherited ability. The standard assumption is that tongue-rolling is a dominant allele at a single gene locus. Which of the following would cast doubt on this assumption?
-Two of these are situations that would cast doubt on this assumption.*A teacher reports that after testing her class on the ability to roll their tongue, with very little effort the non-tongue-rollers can learn to also roll their tongues.*A student who can roll his tongue has a mother and father, both of whom cannot.

Answer 1

The ability to roll the edges of the tongue upward in a U-shape has been considered to be an inherited ability. The standard assumption is that tongue-rolling is a dominant allele at a single gene locus. Which of the following would cast doubt on this assumption?

A)A teacher reports that after testing her class on the ability to roll their tongue, with very little effort the non-tongue-rollers can learn to also roll their tongues.

B)A student who can roll his tongue has a mother and father, both of whom cannot. C)A student who cannot roll his tongue has a mother and father, both of whom can.

D)The non-tongue rollers who learn to roll their tongues and the student who can roll his tongue while his parents cannot are two situations that cast doubt on the heritability issue. The situation where a student cannot roll his tongue while his parents can is inconclusive.

E)Behaviors are not inherited, only structures are inherited.

Answer:

D)The non-tongue rollers who learn to roll their tongues and the student who can roll his tongue while his parents cannot are two situations that cast doubt on the heritability issue. The situation where a student cannot roll his tongue while his parents can is inconclusive.

Explanation:

This is because non tongue rollers who learn to roll their tongues appears to negate the idea of tongue rolling ability to be inherited ability, while also the fact that non tongue rollers having parents who cannot roll their tongues also prove the idea that tongue rolling ability is hereditary.

Hence, the option D)The non-tongue rollers who learn to roll their tongues and the student who can roll his tongue while his parents cannot are two situations that cast doubt on the heritability issue. The situation where a student cannot roll his tongue while his parents can is inconclusive, will surely cast doubt on the assumption, that rolling of tongue is an ability that is hereditary