Where Did Mitochondrial Dna Come From ?

Where Did Mitochondrial DNA Come From ?

Mitochondria are elements resident within the cells. The role of mitochondria is to process food and extract energy which is converted into a form acceptable for usage by the cell. Most DNA is covered in chromosomes within the nucleus, nonetheless mitochondria have their own DNA in small amounts.

Mitochondria with their own DNA are genetic materials known as mitochondrial DNA or mtDNA. In humans there are about 16500 DNA building blocks or base pairs that are covered by mitochondrial DNA. But this is a minute fraction of the total DNA contained in cells.

In sexually reproducing organisms, mitochondria are usually inherited solely from the mother. With mammalian sperm, post-fertilization the mitochondria are usually destroyed by the egg cell. Most mitochondria are present in the tail of the sperm. The tail is what propels sperm cells. Sometimes the tail becomes detached during fertilization.

Because mitochondrial DNA is passed down by the mother, this enables researchers to trace the maternal line far back in time. To achieve this in humans, one or more of the hypervariable control regions of the mitochondrial DNA is arranged in sequences. Hypervariable HVR1 which consists of about 440 base pairs are then compared with similar control regions of specific people in a database to determine the maternal line.

Cases of mitochondrial DNA being inherited from the father have been recorded. These are in lower orders like insects, fruit flies and honey bees. In some mammals, isolated instances have been noticed but in such cases the mitochondria were rejected subsequently.

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Where Did Mitochondrial Dna Come From