The main difference between somatic cell mutations and germ-line mutations is the type of cells in which the mutations occur and whether they can be passed on to offspring.
Somatic cell mutations occur in non-reproductive cells, also known as somatic cells, which make up most of the body tissues. These mutations are not passed on to offspring because they do not affect the genetic material in the gametes (sperm or egg cells). Somatic cell mutations can arise due to environmental factors, such as exposure to radiation or chemicals, or due to errors in DNA replication or repair during cell division. These mutations may cause diseases such as cancer or genetic disorders, but they do not affect the genetic makeup of future generations.
On the other hand, germ-line mutations occur in the cells that give rise to gametes, such as sperm and egg cells. These mutations can be passed on to offspring because they affect the genetic material in the gametes. Germ-line mutations can be inherited from one or both parents or can occur spontaneously during gamete formation. These mutations may cause genetic disorders or increase the risk of developing certain diseases in offspring.
In summary, the main difference between somatic cell mutations and germ-line mutations is that somatic cell mutations occur in non-reproductive cells and are not passed on to offspring, while germ-line mutations occur in reproductive cells and can be passed on to offspring.