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→Mitochondria Inheritance
==Mitochondria Inheritance==
==Mitochondria Inheritance==
In most animal species, mitochondria appear to be primarily inherited through the maternal lineage, though some recent evidence suggests that in rare instances mitochondria may also be inherited via a paternal route. Typically, a sperm carries mitochondria in its tail as an energy source for its long journey to the egg. When the sperm attaches to the egg during fertilization, the tail falls off. Consequently, the only mitochondria the new organism usually gets are from the egg its mother provided. Therefore, unlike [[nuclear DNA]], [[mitochondrial DNA]] doesn't get shuffled every generation. However, the mt genome has a higher rate of mutation, and consists of only some sixteen thousand base pairs. Hence, it is often more useful to gauge the "genetic distance" between two persons (since sequencing after DNA isolation is much quicker and it provides a finer genetic comb). It is also useful for the study of human [[evolution]]. [[Mitochondrial DNA]] is also used in forensic science as a tool for identifying corpses or body parts, and has been implicated in a number of genetic diseases, such as [[Alzheimer's disease]] and [[diabetes]].
In most animal species, mitochondria appear to be primarily inherited through the maternal lineage, though some recent evidence suggests that in rare instances mitochondria may also be inherited via a paternal route. Typically, a sperm carries mitochondria in its tail as an energy source for its long journey to the egg. When the sperm attaches to the egg during fertilization, the tail falls off. Consequently, the only mitochondria the new organism usually gets are from the egg its mother provided. Therefore, unlike [[nuclear DNA]], [[mitochondrial DNA]] doesn't get shuffled every generation. However, the mt genome has a higher rate of mutation, and consists of only some sixteen thousand base pairs. Hence, it is often more useful to gauge the "genetic distance" between two persons (since sequencing after DNA isolation is much quicker and it provides a finer genetic comb). It is also useful for the study of human [[evolution]]. [[Mitochondrial DNA]] is also used in forensic science as a tool for identifying corpses or body parts, and has been implicated in a number of genetic diseases, such as [[Alzheimer's disease]] and [[diabetes]].
Evolutionary biologists posit the existence of a mitochondrial [[Eve]], the most recent progenitor of all our mitochondrial DNA. That is, this individual is the single individual from whom all persons existing today have a totally matrilineal line of descent. Given two persons A and B, mitochondrial Eve E is "the mother of the mother of ... the mother of A," as well as "the mother of the mother of ... the mother of B" for some numbers n(A) and n(B) of iterations of "the mother of", where n(A) need not equal n(B). This theory does not imply that Eve was the *only* female human existing in her time, just that if a modern human A can trace his ancestry to a contemporary of Eve, F, then any line of desent from F to A must include a male. Evolutionists believe that mitochondrial Eve existed some 160,000 years ago in [[Africa]]. Analogously, the Y chromosome is passed only patrilineally, so her male counterpart is referred to as Y-chromosomal [[Adam]].
==Ethnic Differences==
==Ethnic Differences==