A man who cannot roll his tongue marries a woman who can. The woman's mother cannot roll her tongue. What are…

Question

A man who cannot roll his tongue marries a woman who can. The woman's mother cannot roll her tongue. What are the genotypes and phenotypes of their children?

ScanSolve AI Tutor · Accepted Answer

Here's the genetic cross for the F1 generation:

Define the alleles.
- Let $R$ represent the dominant allele for tongue rolling.
- Let $r$ represent the recessive allele for non-rolling.
Determine the genotypes of the parents.
- The man cannot roll his tongue, so his genotype is rr.
- The woman can roll her tongue, but her mother cannot. Since her mother's genotype must be rr, the woman inherited an $r$ allele from her mother. As the woman can roll her tongue, she must have an $R$ allele from her father. Therefore, the woman's genotype is Rr.
Set up the Punnett square for the cross between the man ( $rr$ ) and the woman ( $Rr$ ).
$\begin{array}{|c|c|c|} \hline \textbf{Gametes} & \textbf{R} & \textbf{r} \\ \hline \textbf{r} & Rr & rr \\ \hline \textbf{r} & Rr & rr \\ \hline \end{array}$
Determine the F1 generation genotypes and phenotypes.
- Genotypes:
  
  $Rr$ : 2 out of 4, or 50%
  
  $rr$ : 2 out of 4, or 50%
- Phenotypes:
  
  Rollers ( $Rr$ ): 2 out of 4, or 50%
  
  Non-rollers ( $rr$ ): 2 out of 4, or 50%
The F1 generation will have a 1:1 ratio of heterozygous rollers ( $Rr$ ) to homozygous non-rollers ( $rr$ ).
Phenotypically, there will be a 1:1 ratio of rollers to non-rollers.

A man who cannot roll his tongue marries a woman who can. The woman's mother cannot roll her tongue. What are the genotypes and phenotypes of their children?

Step-by-step solution

Define the alleles.

Determine the genotypes of the parents.

Set up the Punnett square for the cross between the man ( $rr$ ) and the woman ( $Rr$ ).

Determine the F1 generation genotypes and phenotypes.

Still stuck on this one?

More Biology Questions

A man who cannot roll his tongue marries a woman who can. The woman's mother cannot roll her tongue. What are the genotypes and phenotypes of their children?

Step-by-step solution

Define the alleles.

Determine the genotypes of the parents.

Set up the Punnett square for the cross between the man (rrrrrr) and the woman (RrRrRr).

Determine the F1 generation genotypes and phenotypes.

Still stuck on this one?

More Biology Questions

Set up the Punnett square for the cross between the man ( $rr$ ) and the woman ( $Rr$ ).