question_answer

The restriction fragment shown below contains a gene whose recessive allele is lethal. The normal allele has restriction sites for enzymes \[BamI\]at sites I and II whereas recessive allele lacks site I. An individual who has a sister with the lethal trait is being tested to determine if he is a carrier of that lethal trait.

Which of the band patterns would be produced on a gel if he is a carrier?

A)

B)

C)

D)

Correct Answer: D

Solution :

Normal allele

A carrier individual will have both the alleles- normal and recessive alleles. When digested with\[BamI\], total five fragments (3 fragments from normal allele of different sizes and 2 fragments of the same size from recessive allele) will be obtained in the gel.