The Talmud an ancient book of Jewish civil and religious law

The Talmud, an ancient book of Jewish civil and religious laws, states that if a woman bears two sons who die of bleeding after circumcision (removal of the foreskin from the penis), any additional sons that she has should not be circumcised. (The bleeding is most likely due to the X-linked disorder hemophilia.) Furthermore, the Talmud states that the sons of her sisters must not be circumcised, whereas the sons of her brothers should. Is this religious law consistent with sound genetic principles? Explain your answer.

Solution

Let us try to analyze the genetic basis of the Talmud religious law:

Hemophilia is an X-linked recessive disorder which is characterized by excessive uncontrolled bleeding upon a cut or injury. The recessive allele for hemophilia might be present in women who are carrier for the disease ( Affected women do not survive up till the age of childbirth).

Hence let the genotype of the affected woman be : XX ^h (Let X^h be the recessive allele for hemophilia)

The sons who bled upon circumcision are affected individuals \'and bear the recessive allele. Their genotype are : X^hY

Now, it is said by the law that the affected woman\'s sisters sons should not be circumcised. Let us assume that the sister also carrier for the disease, having genotype XX^h

Since both the sisters are XX^h, we can predict the genotype of their parents:

Prediction 1 : Father XY (normal) Mother XX^h (Carrier)

Prediction 2: Father (X^hY) (affected) Mother (XX^h) (Carrier)

Prediction 3: Father (X^hY) (affected) Mother XX (Normal)

Hence, the brother of the sisters as mentioned might be affected or normal.

Even if he is affected, his sons will not receive the recessive allele from him and can be circumcised safely, given the fact that his wife is normal. Because son\'s do not receive the X allele from his father.

Thus the Talmud\'s religious law is consistent with genetic principles.