User:Hillgentleman/mitochondrial eve

 草文，歡迎大家一齊寫。

線粒體夏娃（Mitochondrial Eve, mt-mrca）係個研究員假想中嘅女人，指全人類嘅母系最近共同祖先(en:matrilineal most recent common ancestor, MRCA)。十萬幾年來，線粒體 DNA(en:mtDNA)由每個阿媽傳畀細路；而家每一個生人身上嘅 mtDNA 都係來自佢嘅。相對佢嘅係Y-染色體亞當(en:Y-chromosomal Adam)，即係父系嘅最近共同祖先(en:patrilineal most recent common ancestor)，不過佢哋兩個人唔係同時代嘅。

一般相信佢嚮約 140,000 年前喺而家嘅埃塞俄比亞、肯雅或坦桑尼亞一帶生活。 段時間係用分子鐘(en:molecular clock)技術計嘅，對比時間經過同埋觀察到嘅基因漂移(en:genetic drift)。

Mitochondrial Eve is the most recent common ancestor (MRCA) of all humans via the mitochondrial DNA pathway, not the unqualified MRCA of all humanity. All living humans can trace their ancestry back to the MRCA via at least one of their parents, but Mitochondrial Eve can only be reached via the maternal line. Therefore, she necessarily lived much longer ago than the MRCA of all humanity.

The existence of Mitochondrial Eve and Y-chromosomal Adam does not imply the existence of population bottlenecks or a first couple. They each lived within a large human population at a different time. Some of their contemporaries have no living descendants today, and others are ancestors of all people alive today. No contemporary of Mitochondrial Eve or Y-chromosomal Adam is an ancestor of only a subset of people alive today, because both of them lived much longer ago than the identical ancestors point.