GENERAL HISTOLOGY

Detailed explanation-1: -Mitotic nondisjunction can cause somatic mosaicism, with the chromosome imbalance only reflected in the direct offspring of the original cell where the nondisjunction occurred. This can cause some forms of cancer, including retinoblastoma.

Detailed explanation-2: -Mutations can result from errors in DNA replication during cell division, exposure to mutagens or a viral infection.

Detailed explanation-3: -During pregnancy, an error in mitosis can occur. If the chromosomes don’t split into equal halves, the new cells can have an extra chromosome (47 total) or have a missing chromosome (45 total).

Detailed explanation-4: -Nondisjunction. Nondisjunction is the failure of homologous chromosomes (chromatids) to separate properly during meiotic cell division.

Detailed explanation-5: -As opposed to germ-line mutations, somatic mutations occur in cells found elsewhere in an organism’s body. Such mutations are passed to daughter cells during the process of mitosis (Figure 2), but they are not passed to offspring conceived via sexual reproduction.