Question

In The Princess, Bride Montoyo has spent his adult life seeking revenge on the six-fingered man who killed his father. Polydactyly, the presence of extra fingers or toes, is caused by a dominant allele.
If five individuals per 1000 births are affected by the condition, what is the frequency of the polydactyly allele?
A)0.003
B)0.005
C)0.071
D)0.995

Answer 1

When the person is born with extra fingers or toes then the condition is known as polydactyly. It comes from the Greek word-poly means many and dactylos means digits. In polydactyly, mostly extra digits grow next to the fifth finger or toes and it runs in families. It is also caused by genetic mutations or environmental causes.

Complete answer:
-Polydactyly is a condition that is inherited and the person is having extra fingers or toes which is caused by a dominant allele of a gene which means polydactyly can be passed by just one allele from one parent if they have the disorder.
-How common is allele occurring in a population is referred to as an allele frequency. The allele frequency is generally determined by counting how many times the allele appears in the population then dividing it by the total number of copies of the gene.
-So, to calculate the allelic frequency, we simply divide the number of alleles by the total number of alleles present in the population.
-Therefore, the frequency of the polydactyly allele, if five individuals per 1000 birth are affected by the condition, is 5/1000 = 0.005

Additional Information: -Mostly it occurs without any other abnormalities. The Polydactyly is called as isolated or non syndromic polydactyly and rarely associated with another genetic condition known as syndromic polydactyly.
-Isolated polydactyly- isolated polydactyly can be classified by the position of extra digits i.e Postaxial polydactyly, Preaxial Polydactyly, and Central Polydactyly.
Postaxial polydactyly - It generally occurs on the outside of the hand or foot, where the fifth digit is.
Preaxial polydactyly - It generally occurs on the inside of the hand or foot, where the thumb or big toe is.
Central polydactyly - It generally occurs in the middle digits of the hand or foot. It rarely occurs..
So, the correct answer is,”0.005”

Note: -In polydactyly, the extra digits may be complete or fully functional or sometimes it may be partially formed with the bone or just with the small mass of soft tissue.
-It is also known as hyperdactyly which results in supernumerary fingers or toes.
-This condition is totally opposite from the oligodactyly which means fewer fingers or toes.