Question

For tongue rolling, how many alternative forms of genes are present?
A. 1
B. 2
C. 3
D. 4

Answer 1

Hint: A gene encoding a trait generally has two contrasting and opposite variations, which are known as alleles. For example, if we look at Mendel’s experiment with pea plants, he has described the plant to be either tall or dwarf. So, in that case, the height of the plant was a trait, and tallness and dwarfness were the 2 contrasting forms (alleles).

Complete answer:
Tongue rolling is the ability to stick the tongue out of the mouth and roll it into a tube-like structure. For tongue rolling, two alternate forms of genes are present. The two variations are:
- The ability to roll tongue
- The inability to roll tongue
The ability to roll the tongue is a dominant trait, whereas the inability to do so is recessive. So, if a person gets one gene for the ability and one for the inability, he/she would still be able to roll their tongue. The inability would arise only when the person inherits two genes for the inability to roll the tongue.

So, as per theory, a person can either roll his tongue or not as there are only two alternative forms of the gene. Another example of such a trait is the cloverleaf tongue, in which the person can fold his tongue in multiple ways that eventually resembles a cloverleaf.

Hence, the correct answer is option (B).

Note: Even though the ability to roll the tongue is still a major part of understanding genetics, there have been a few studies that have shown that tongue rolling is not always inheritable. There are certain non-genetic factors that are able to influence tongue rolling. The muscular strength of the tongue is one such factor.