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The somatic mutation theory of ageing states that accumulation of mutations in somatic cells is the primary cause of aging. A comparison of somatic mutation rate across several mammal species found that the total number of accumulated mutations at the end of lifespan was roughly equal across a broad range of lifespans. [16]
For example, in mammals, somatic cells make up the internal organs, skin, bones, blood, and connective tissue. [1] In most animals, separation of germ cells from somatic cells (germline development) occurs during early stages of development. Once this segregation has occurred in the embryo, any mutation outside of the germline cells can not be ...
IAA is listed in its MSDS as mutagenic to mammalian somatic cells, and possibly carcinogenic based on animal data. It may cause adverse reproductive effects (fetotoxicity) and birth defects based on animal data. No human data as of 2008. [27] It is listed as a potential skin, eye, and respiratory irritant, and users are warned not to ingest it.
Cloning from somatic cells rather than germ cells may begin life with a higher initial load of damage. Dolly the sheep died young from a contagious lung disease, but data on an entire population of cloned individuals would be necessary to measure mortality rates and quantify aging. [citation needed]
It is the retention in adults of traits previously seen only in the young. Such retention is important in evolutionary biology, domestication, and evolutionary developmental biology. Some authors define paedomorphism as the retention of larval traits, as seen in salamanders. [11] [12] [13]
A mutation that arises soon after fertilization, but before germline and somatic cells are determined, then the mutation will be present in a large proportion of the individual's cell with no bias towards germline or somatic cells, this is also called a gonosomal mutation. [4]
A change in the genetic structure that is not inherited from a parent, and also not passed to offspring, is called a somatic mutation. [89] Somatic mutations are not inherited by an organism's offspring because they do not affect the germline. However, they are passed down to all the progeny of a mutated cell within the same organism during ...
In mammals, somatic cells make up all the internal organs, skin, bones, blood and connective tissue, while mammalian germ cells give rise to spermatozoa and ova which fuse during fertilization to produce a cell called a zygote, which divides and differentiates into the cells of an embryo. There are approximately 220 types of somatic cell in the ...