The Evolution Of Eukaryotic Cells

1102 Words Nov 16th, 2015 5 Pages
After the unanticipated discovery of a separate mitochondrial genome, there have been new insights into its inheritance and mutation. There is enough evidence to bolster the fact that fusion between a-proteobacteria and archaebacteria is an integral event in evolution of eukaryotic cells. However, it has also been conjectured that eukaryotic cell may have originated from prokaryotes. As a part of this evolution, many mitochondrial ancestral genes were lost. These are the genes that were no longer required in their new host cell environment. All eukaryotes contain genes of mitochondrial origin in their nuclear genome. However, this is only true for a few genes. Studies indicate that humans and mice have only 35% of mitochondrial gene products that are similar to bacteria Rickettsia. Remaining mitochondrial proteins are derived from either non-mitochondrial nuclear genes or as a result of horizontal gene transfer events. Mitochondria have developed different states during the evolution of eukaryotic cell. Aerobic mitochondria retain a small mtDNA while anaerobic mitochondria and hydrogen-producing mitochondria alter the function of respiratory chain and also maintain mtDNA.
Most animal mitochondrial genome obeys a specific genome composition. However, there are exceptions where variations have been observed. The genes of mtDNA are tightly packed together with minimal non-coding DNA. However, one large non-coding region called as D-loop, containing regulatory elements for…
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