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Did you know? Parents may not be sick, but their children may be sick due to genetic mutations!
In genetics and genetics, certain key concepts such as "germline mutation" may be overlooked by many people. These mutations occur in germ cells and may affect offspring, even in cases where the parents do not have the genetic disease.
Germline mutations are mutations that can be detected in germ cells and can only be passed on to offspring when a zygote is formed after fertilization.
There is an essential difference between germline mutations and somatic mutations. Germline mutations are mutations that occur in sperm or eggs and can be passed on to offspring but do not affect all somatic cells of the parent. Such mutations may cause a child to suffer from a genetic disease, but the parents may not show the same symptoms.
When mutations occur
The emergence of germline mutations may occur at different stages of development before or after fertilization. The timing of a mutation's emergence affects its impact on future generations. If the mutation occurs during the formation of the sperm or egg, the mutation will be present in every cell of the child's body; if the mutation occurs after fertilization but before the differentiation of germ cells and somatic cells, the mutation will be present in one cell of the individual. In most cells, it is not biased toward germ cells or somatic cells but is distributed in a random pattern.
Causes of germline mutations
Endogenous factors
Germline mutations are often caused by endogenous factors, such as errors during cell replication and oxidative damage. Such mutations may even occur frequently due to the high frequency of germ cell division. The sexes of the parents also differ in the type and frequency of mutations, since the mother's egg enters a quiescent state after production, while the father's sperm is constantly participating in cell division.
In the male germline, the rate of spontaneous mutations increases with age, and this rate of growth is lower than that of somatic tissue.
Exogenous factors
Germline mutations can also occur due to the influence of exogenous factors. These factors include harmful chemicals and ionizing radiation, among others. Although germ cells are not often exposed to ultraviolet light, the presence of these exogenous mutations also affects genetic integrity.
Clinical significance
Different germline mutations will affect an individual's performance depending on the overall situation of their genome. A dominant mutation requires only a single mutated gene to display a disease phenotype, whereas a recessive mutation requires both alleles to be mutated to display a disease phenotype. The complexity of this process explains why children may develop genetic diseases that are not present in either parent.
Cancer and Heredity
The occurrence of mutations in tumor suppressor or promoter genes may predispose individuals to the development of tumors. It is estimated that 5-10% of cancer cases are related to inherited gene mutations, which can develop in germ cells and be inherited by offspring.
Case studies of special diseases
For example, Huntington's disease is an auto-dominant mutation that causes degeneration of the brain and develops uncontrolled movements. Most individuals with the disease have at least one parent who carries the mutant allele, and their children have a relative 50% chance of inheriting the mutation.
Current therapies and CRISPR technology
With the advancement of genome editing technology, treatment options for many genetic diseases are already being explored. The emergence of the CRISPR/Cas9 system provides new opportunities for the repair of germline mutations. The technology's ability to pinpoint genes for editing or repair has the potential to revolutionize future treatments.
How to face the impact that genetic mutations may have on future generations?
