The SNDM hypothesis, short for "Single Nucleotide Deletion Model", is a theory explaining the origin of mitochondrial DNA (mtDNA), a type of genetic material found in mitochondria, the powerhouses of cells.
This hypothesis suggests that mtDNA originated from a single deletion event in a bacterial genome. This event resulted in a smaller, circular DNA molecule that was then incorporated into the host cell's mitochondria.
The SNDM hypothesis is supported by several pieces of evidence:
- Structural similarities: mtDNA and bacterial DNA share structural similarities, such as their circular shape and the presence of genes involved in energy production.
- Genetic code: The genetic code used by mtDNA is almost identical to that of bacteria.
- Phylogenetic analysis: Phylogenetic studies show that mtDNA is closely related to certain groups of bacteria.
However, the SNDM hypothesis is not without its critics. Some argue that the deletion event is too large to be plausible, and that other mechanisms, such as gene transfer, may have played a role in the origin of mtDNA.
Despite these criticisms, the SNDM hypothesis remains a widely accepted theory explaining the origin of mtDNA. It provides a simple and elegant explanation for the similarities between mtDNA and bacterial DNA.
