Unequal crossing over during prophase I can result in one sister chromosome with a deletion and another with a duplication. A mutated form of hemoglobin, so-called hemoglobin Lepore, exists in the human population. Hemoglobin Lepore has a deleted series of amino acids. If this mutated form was caused by unequal crossing over, what would be an expected consequence?
A) If it is still maintained in the human population, hemoglobin Lepore must be selected for in evolution.
B) There should also be persons whose hemoglobin contains two copies of the series of amino acids that is deleted in hemoglobin Lepore.
C) Each of the genes in the hemoglobin gene family must show the same deletion.
D) The deleted gene must have undergone exon shuffling.
E) The deleted region must be located in a different area of the individual's genome.

Question

Quizplus · Accepted Answer

Unequal crossing over during meiosis can result in a chromosome with a deletion and another with a duplication. If the mutated form of hemoglobin (hemoglobin Lepore) was caused by unequal crossing over, it could result in one chromosome with a series of amino acids deleted and another chromosome with two copies of that same series of amino acids. Therefore, there should also be persons whose hemoglobin contains two copies of the series of amino acids that is deleted in hemoglobin Lepore. Choice (A) is incorrect because hemoglobin Lepore may not necessarily be selected for in evolution; it could remain in the population due to genetic drift. Choice (C) is incorrect because the deletion could have occurred only in the specific gene responsible for hemoglobin Lepore, not necessarily in all the genes in the hemoglobin gene family. Choice (D) is incorrect because the deletion was specific and not as a result of exon shuffling. Choice (E) is incorrect because the deletion occurred in the hemoglobin gene and not a different area of the individual's genome.

Unequal Crossing Over During Prophase I Can Result in One