| From: Cybernaut ® | 04/09/2000
13:15:00 |
| Subject: Adam's Rib-bone! | post id:
128009 |
| 'Eve' is a hypothetical
individual African referred to as the hominid 'mother' of humankind. Her
existence has been inferred from the knowledge that mitochondrial DNA is
passed unchanged from mother to child (with some occasional mutation).
That allows scientists to make a genetic trace from modern individuals all
the way back through to the original Eve, from our knowledge of how
mitochondrial DNA is transferred to the new generation. I would imagine
that the evolution of mitochondrial DNA would parody the evolution of the
chromosomal DNA of asexual species (such as bacterium and other single
celled organisms). In other words, it evolves, but not in the same way
that sexual gametes provide. Any comments from those intimately familiar
with these processes? | |
| From: CJW ® | 04/09/2000
18:15:00 |
| Subject: re: Adam's Rib-bone! | post id:
128265 |
| such as
bacterium The way that bacteria go around exchanging info on plasmids and gulping up DNA that's around the place hardly means that they are going to be similar to other asexual orgs. I have often wondered how fungi improve themselves. They seem so big and slow. | |
| From: Carmel ® | 11/09/2000
17:33:00 |
| Subject: re: Adam's Rib-bone! | post id:
132685 |
| Mitochondrial
Eve. Depending on who you talk to, She's a bit controversial. However, you've got the basic theory right. Mitochondrial DNA is passed, unchnaged (for the most part) from Mother to child. Therefore, by analysing the sequences of the mtDNA from various populations, it is possible to form an evolutionary tree... steadily going back and back until you reach the original 'mother'. Now technically, this is all perfectly true and even makes somekind of sense. Except for a couple of very important things: whilst the mtDNA contains several essential and necessary genes, it mutates and 'evolves' completely independently of the chromosomal DNA. There are also a heck of a lot more genes in the chromosomal DNA. And evoltuion progresses due to changes that promote a better chance of having grandchildren. And there is not necessarily ANY correlation between having the oldest mtDNA and being the oldest civilisation, because of this fact. The other thing that provides a flaw in this theory is that in order to make sense of an evoltuionary tree, in order for it to mean anything, it must be 'rooted', which means you have to pick the 'root', based on the information you have. Depending on the root you chose, the shape of the tree can be wildly different. However, despite this, I tend to think that Mitochondiral Eve is the closest we have come to understanding where humans came from. | |