Human mitochondrial DNA (inherited only from one's mother) and Y chromosome DNA (from one's father) show coalescence at around 140,000 and 60,000 years ago respectively. In other words, all living humans' female line ancestry trace back to a single female (Mitochondrial Eve) at around 140,000 years ago. Via the male line, all humans can trace their ancestry back to a single male (Y-chromosomal Adam) at around 60,000 to 90,000 years ago.[2]
However, such coalescence is genetically expected and does not, in itself, indicate a population bottleneck, because mitochondrial DNA and Y-chromosome DNA are only a small part of the entire genome, and are atypical in that they are inherited exclusively through the mother or through the father, respectively. Most genes in the genome are inherited from either father or mother, thus can be traced back in time via either matrilineal or patrilineal ancestry.[3] Research on many (but not necessarily most) genes find different coalescence points from 2 million years ago to 0 years ago when different genes are considered, thus disproving the existence of more recent extreme bottlenecks (i.e. a single breeding pair).[4][5]
This is consistent with the Toba catastrophe theory which suggests that a bottleneck of the human population occurred c. 70,000 years ago, proposing that the human population was reduced to c.15,000 individuals[5] when the Toba supervolcano in Indonesia erupted and triggered a major environmental change. The theory is based on geological evidences of sudden climate change, and on coalescence evidences of some genes (including mitochondrial DNA, Y-chromosome and some nuclear genes)[6] and the relatively low level of genetic variation with humans.[5]
On the other hand, in 2000, a Molecular Biology and Evolution paper suggested a transplanting model or a 'long bottleneck' to account for the limited genetic variation, rather than a catastrophic environmental change.[7] This would be consistent with suggestions that in sub-Saharan Africa numbers could have dropped at times as low as 2,000, for perhaps as long as 100,000 years, before numbers began to expand again in the Late Stone Age[8]"
oh w8.....NO 6000 YEARS AGO?!
gj at auto flaiming yourself.
not only that, they traced the genome to one ancestor, they didn't test ALL the genomes out there for starters, and this doesn't say anythign about the ENTIRE population, EG: they other pairs' ofspring could have died out during the course of history.
and now lets have some fun with your source...
". On average, the individuals in our dataset differed from the Eve consensus by 21.6 nucleotides."
"Given the high mutation rate within mitochondria"
"Uniparental inheritance leads to little opportunity for genetic recombination between different lineages of mitochondria, although a single mitochondrion can contain 2–10 copies of its DNA.[46] For this reason, mitochondrial DNA usually is thought to reproduce by binary fission. What recombination does take place maintains genetic integrity rather than maintaining diversity. However, there are studies showing evidence of recombination in mitochondrial DNA. It is clear that the enzymes necessary for recombination are present in mammalian cells.[66] Further, evidence suggests that animal mitochondria can undergo recombination.[67] The data are a bit more controversial in humans, although indirect evidence of recombination exists.[68][69] If recombination does not occur, the whole mitochondrial DNA sequence represents a single haplotype, which makes it useful for studying the evolutionary history of populations."
k to ANY1 with an understandign of biology, you can see that the mutation rate of mDNA is...quite low.UNlike what IRC here claims.
"
The near-absence of genetic recombination in mitochondrial DNA makes it a useful source of information for scientists involved in population genetics and evolutionary biology.[70] Because all the mitochondrial DNA is inherited as a single unit, or haplotype, the relationships between mitochondrial DNA from different individuals can be represented as a gene tree. Patterns in these gene trees can be used to infer the evolutionary history of populations. The classic example of this is in human evolutionary genetics, where the molecular clock can be used to provide a recent date for mitochondrial Eve.[71][72] This is often interpreted as strong support for a recent modern human expansion out of Africa.[73] Another human example is the sequencing of mitochondrial DNA from Neanderthal bones. The relatively-large evolutionary distance between the mitochondrial DNA sequences of Neanderthals and living humans has been interpreted as evidence for lack of interbreeding between Neanderthals and anatomically-modern humans.[74]
However, mitochondrial DNA reflects the history of only females in a population and so may not represent the history of the population as a whole. This can be partially overcome by the use of paternal genetic sequences, such as the non-recombining region of the Y-chromosome.[73] In a broader sense, only studies that also include nuclear DNA can provide a comprehensive evolutionary history of a population.[75]"
ahw well....swing and a miss 9tails..
or swing and a fail.