What is a germline mutation?

A germline mutation refers specifically to a change in the DNA sequence that occurs in gametes, which are the reproductive cells such as sperm and eggs. This is significant because mutations in these cells can be transmitted to the next generation when fertilization occurs. Consequently, any offspring developed from these gametes may inherit the mutation, potentially leading to genetic conditions or traits in the future generations.

In contrast, mutations that happen in somatic cells, which are any cells in the body that are not gametes, do not get passed on to offspring. They might lead to health issues like cancer but are not inherited by subsequent generations. Similarly, environmental factors can cause mutations, but not all mutations due to environmental influences are classified as germline mutations. Therefore, the essence of a germline mutation lies in its ability to be passed down through generations via reproductive cells.