Question

The ability for people to roll their tongue is dominant to people who cannot. If a tongue roller and a non-tongue roller were crossed, the highest percentage of potential non-tongue roller offspring would be which of the following?

Answer 1

50%

Step-by-step explanation:

Tounge rolling is a dominate trait, so that means it would have to have at least 1 captial letter in it't genotype (assuming captial letters refer to the dominate trait). But, because the demonate trait covers any non-dominate traits, you can have a lower case letter in the genotype while still having someone be a tounge roller (assuming lower case letters are non-dominate traits)

Because non-tounge rollers are non-dominate, they must have two lower case letters in their genotype.

This leaves you with the two genotypes of :

AA or Aa (tounge rollers)

aa (non-tounge rollers)

When crossing AA with aa in a punette, every outcome is Aa. This leaves you with no potentional non-tounge rollers. But, you can still cross Aa with aa, because as said before Aa has a dominate gene, so it would result in someone with the tounge rolling ability.

When crossing Aa and aa in a punnet sqaure, you can get outcomes. Aa or aa. 2 of teh 4 options are Aa, and 2 of teh four options are aa. This means half, or 50% of the offspring are predicted to be non-tounge rollers, showing the high ercentage must be 50%.