Friday, December 10, 2010

DNA Inheritance

DNA Identity Testing laboratory of Bio-Synthesis provide mitochondrial DNA analysis. This nuclear and mitochondrial DNA is thought to be of separate evolutionary origin, with the mtDNA being derived from the circular genomes of the bacteria that were engulfed by the early ancestors of today's eukaryotic cells. Each mitochondrion is estimated to contain 2-10 mtDNA copies.

Mitochondrial Inheritance
The fact that mitochondrial DNA is maternally inherited enables researchers to trace maternal lineage far back in time. (Y chromosomal DNA, paternally inherited, is used in an analogous way to trace the agnate lineage.) This is accomplished in humans by sequencing one or more of the hyper variable control regions (HVR1 or HVR2) of the mitochondrial DNA. HVR1 consists of about 440 base pairs. These 440 base pairs are then compared to the control regions of other individuals (either specific people or subjects in a database) to determine maternal lineage. Most often, the comparison is made to the revised.

Male Inheritance
It has been reported that mitochondria can occasionally be inherited from the father in some species such as mussels. Paternally inherited mitochondria have also been reported in some insects such as the fruit fly and the honeybee. Evidence supports rare instances of male mitochondrial inheritance in some mammals as well. Specifically, documented occurrences exist for mice, where the male-inherited mitochondrion was subsequently rejected. It has also been found in sheep, and in cloned cattle. It has been found in a single case in a human male and was linked to infertility.

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