In humans, tongue rolling is dominant over non-rolling. A man who can roll his tongue marries a woman who cannot. They have 8 children, of which 6 can roll their tongue. What is the genotype of these 6 children?
A
Rr
B
rr
C
RR
D
6R
To determine the genotype of the children who can roll their tongue, we need to determine the possible genotypes of the parents.
Since tongue rolling is dominant over non-rolling, the man who can roll his tongue must be heterozygous (Rr).
The woman who cannot roll her tongue must be homozygous recessive (rr).
When these two parents with genotypes Rr and rr reproduce, they can produce two different genotypes in their offspring:
- Rr: Having one dominant allele (R) and one recessive allele (r). This genotype allows the individual to roll their tongue.
- rr: Having two recessive alleles (r). This genotype does not allow the individual to roll their tongue.
Out of the 8 children, 6 can roll their tongue. This means that they must have at least one dominant allele (R) for tongue rolling.
Therefore, the genotype of these 6 children would be Rr (option A).