In humans, two traits, rolling the tongue and the ability to taste PTC, depend o
ID: 7974 • Letter: I
Question
In humans, two traits, rolling the tongue and the ability to taste PTC, depend on separate dominant genes located on different chromosomes. A man that can roll the tongue (assume he is homozygous) that cannot taste PTC married a woman that can not roll the tongue that can taste PTC (whose mother can not taste this chemical). What is the probability that their first child will: (write down the cross and your calculations)a. Either not being able to roll the tongue or not being able to taste PTC?
b. Being both able to roll the tongue and able to taste PTC?
c. Being both able to roll the tongue and not able to taste PTC?
d. Either not being able to roll the tongue or being able to taste PTC?
Explanation / Answer
In humans, two traits,
rolling the tongue -------------------- dominant genes- R
ability to taste PTC, dominant genes---------------T
A man that can roll the tongue (assume he is homozygous) that cannot taste PTC ------------RR tt
woman that can not roll the tongue that can taste PTC (whose mother can not taste this chemical)---rrTt
RR tt x rrTt
Rt rT rt
rT
rt
Rt
Rt rT
roll the tongue taste PTC
Rt rt
roll the non taster
Rt
Rt rT
roll the tongue taste PTC
Rt rt
roll the tongue non taster
a. Either not being able to roll the tongue or not being able to taste PTC?
0%
b. Being both able to roll the tongue and able to taste PTC?
50%
c. Being both able to roll the tongue and not able to taste PTC?
50%
d. Either not being able to roll the tongue or being able to taste PTC?
0%
rT
rt
Rt
Rt rT
roll the tongue taste PTC
Rt rt
roll the non taster
Rt
Rt rT
roll the tongue taste PTC
Rt rt
roll the tongue non taster