基因遺傳問題

This depends on whether the homozygous individual has dominant or recessive allele.

Case 1:

If the homozygous individual has dominant allele, then ALL the children can roll their tongues. It is because each children must receive one allele from each parent. Since there must be a dominant allele from the homozygous dominant individual, all the children can roll their tongues.

Case 2:

If the homozygous individual has recessive allele, then the probability for EACH children can roll their tongues is 1/2. This is because each children must receive a recessive allele from the homozygous recessive individual and the probability to receive a dominant allele from the heterozygous individual is 1/2. Therefore, the children have 1/2 chance which they can roll their tongues. To conclude, the number of children that are expected to roll their tongues is 4.


I hope that I can help you to solve the problem ^^~

plz 中文
唔係好睇得明