Question

Consider a chromosome that has been broken in two places to produce three chromosomal fragments. The middle fragment is lost and degraded. The rejoining of the outer fragments will create a chromosome with a(n) _____ deletion.

Answer 1

The chromosomal structure resulting from the loss and degradation of the middle fragment with the outer fragments rejoining will exhibit a chromosomal deletion. Deletion mutations can remove essential genes and result in disorders with physical and mental abnormalities such as cystic fibrosis and cri-du-chat syndrome.

Step-by-step explanation:

If a chromosome is broken in two places, resulting in three fragments, and the middle fragment is lost and degraded while the outer fragments rejoin, the resulting structure would display a chromosomal deletion. A deletion is a mutation involving the loss of a segment of a chromosome. This mutation can result in the absence of many genes that were originally present on the chromosome, potentially leading to physical and mental abnormalities. Deletion mutations can have serious consequences as seen in disorders such as cystic fibrosis and cri-du-chat syndrome. In cystic fibrosis, for example, the loss of three nucleotides causes the absence of the amino acid phenylalanine, affecting the protein's function. On the other hand, cri-du-chat syndrome is characterized by a deletion in chromosome 5, which affects the nervous system and causes distinctive physical features.